Commit Graph

2211 Commits

Author SHA1 Message Date
Juan Quintela
0743f41fd2 migration: migration_rate_limit_reset() don't need the QEMUFile
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231025091117.6342-9-quintela@redhat.com>
2023-10-31 08:44:33 +01:00
Juan Quintela
f57e5a6ce5 migration: migration_transferred_bytes() don't need the QEMUFile
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231025091117.6342-8-quintela@redhat.com>
2023-10-31 08:44:33 +01:00
Juan Quintela
e9c0eed7c2 qemu-file: Remove _noflush from qemu_file_transferred_noflush()
qemu_file_transferred() don't exist anymore, so we can reuse the name.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>

Message-ID: <20231025091117.6342-7-quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-10-31 08:44:33 +01:00
Juan Quintela
e833cad7e7 qemu_file: Remove unused qemu_file_transferred()
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231025091117.6342-6-quintela@redhat.com>
2023-10-31 08:44:33 +01:00
Juan Quintela
737840e2c6 migration: Use the number of transferred bytes directly
We only use migration_transferred_bytes() to calculate the rate_limit,
for that we don't need to flush whatever is on the qemu_file buffer.
Remember that the buffer is really small (normal case is 32K if we use
iov's can be 64 * TARGET_PAGE_SIZE), so this is not relevant to
calculations.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231025091117.6342-5-quintela@redhat.com>
2023-10-31 08:44:33 +01:00
Juan Quintela
5e2652185b qemu_file: total_transferred is not used anymore
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231025091117.6342-4-quintela@redhat.com>
2023-10-31 08:44:33 +01:00
Juan Quintela
2d897237e0 qemu_file: Use a stat64 for qemu_file_transferred
This way we can read it from any thread.
I checked that it gives the same value as the current one.  We never
use two qemu_files at the same time.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231025091117.6342-3-quintela@redhat.com>
2023-10-31 08:44:33 +01:00
Juan Quintela
cc8bf57d56 qemu-file: Don't increment qemu_file_transferred at qemu_file_fill_buffer
We only call qemu_file_transferred_* on the sending side. Remove the
increment at qemu_file_fill_buffer() and add asserts to
qemu_file_transferred* functions.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231025091117.6342-2-quintela@redhat.com>
2023-10-31 08:44:33 +01:00
Peter Xu
a2326705e5 migration: Stop migration immediately in RDMA error paths
In multiple places, RDMA errors are handled in a strange way, where it only
sets qemu_file_set_error() but not stop the migration immediately.

It's not obvious what will happen later if there is already an error.  Make
all such failures stop migration immediately.

Cc: Zhijian Li (Fujitsu) <lizhijian@fujitsu.com>
Cc: Markus Armbruster <armbru@redhat.com>
Cc: Juan Quintela <quintela@redhat.com>
Cc: Fabiano Rosas <farosas@suse.de>
Reported-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231024163933.516546-1-peterx@redhat.com>
2023-10-31 08:44:33 +01:00
Juan Quintela
864128df46 migration: Deprecate old compression method
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231018115513.2163-6-quintela@redhat.com>
2023-10-31 08:44:33 +01:00
Juan Quintela
66db46ca83 migration: Deprecate block migration
It is obsolete.  It is better to use driver-mirror with NBD instead.

CC: Kevin Wolf <kwolf@redhat.com>
CC: Eric Blake <eblake@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Hanna Czenczek <hreitz@redhat.com>

Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231018115513.2163-5-quintela@redhat.com>
2023-10-31 08:44:33 +01:00
Juan Quintela
8846b5bfca migration: migrate 'blk' command option is deprecated.
Use blocked-mirror with NBD instead.

Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231018115513.2163-4-quintela@redhat.com>
2023-10-31 08:44:33 +01:00
Juan Quintela
40101f320d migration: migrate 'inc' command option is deprecated.
Use blockdev-mirror with NBD instead.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231018115513.2163-3-quintela@redhat.com>
2023-10-31 08:44:33 +01:00
Marc-André Lureau
cd4c0da6db migration: set file error on subsection loading
commit 13cde50889 ("vmstate: Return error in case of error") sets
QemuFile error to stop reading from it and report to the caller (checked
by unit tests). We should do the same on subsection loading error.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231024084043.2926316-8-marcandre.lureau@redhat.com>
2023-10-30 17:44:03 +01:00
Marc-André Lureau
4d8bdc2ae0 migration: rename vmstate_save_needed->vmstate_section_needed
The function is used on save at this point. The following commits will
use it on load.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231024084043.2926316-5-marcandre.lureau@redhat.com>
2023-10-30 17:44:03 +01:00
Thomas Huth
bc3d41a9f6 migration/ram: Fix compilation with -Wshadow=local
Rename the variable here to avoid that it shadows a variable from
the beginning of the function scope. With this change the code now
successfully compiles with -Wshadow=local.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231024092220.55305-1-thuth@redhat.com>
2023-10-30 17:44:03 +01:00
Juan Quintela
8258f2fa06 migration: Rename ram_compressed_pages() to compress_ram_pages()
We are moving to have all functions exported from ram-compress.c to
start with compress_.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231019110724.15324-12-quintela@redhat.com>
2023-10-30 17:41:55 +01:00
Juan Quintela
f639cfe515 migration: Merge flush_compressed_data() and compress_flush_data()
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231019110724.15324-11-quintela@redhat.com>
2023-10-30 17:41:55 +01:00
Juan Quintela
8020bc9a77 migration: Move ram_flush_compressed_data() to ram-compress.c
As we export it, rename it compress_flush_data().

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231019110724.15324-10-quintela@redhat.com>
2023-10-30 17:41:55 +01:00
Juan Quintela
742ec5f338 migration: Export send_queued_data()
This function is only used for compression.  So we rename it as
compress_send_queued_data().  We put it on ram-compress.h because we
are moving it later to ram-compress.c.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231019110724.15324-9-quintela@redhat.com>
2023-10-30 17:41:55 +01:00
Juan Quintela
fb36fb275f migration: Create compress_update_rates()
So we can move more compression_counters stuff to ram-compress.c.
Create compression_counters struct to add the stuff that was on
MigrationState.

Reviewed-by: Lukas Straub <lukasstraub2@web.de>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231019110724.15324-8-quintela@redhat.com>
2023-10-30 17:41:55 +01:00
Juan Quintela
250b1d7ef6 migration: Move busy++ to migrate_with_multithread
And now we can simplify save_compress_page().

Reviewed-by: Lukas Straub <lukasstraub2@web.de>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231019110724.15324-7-quintela@redhat.com>
2023-10-30 17:41:55 +01:00
Juan Quintela
b6e19b6de8 migration: Simplify compress_page_with_multithread()
Move the goto to a while true.

Reviewed-by: Lukas Straub <lukasstraub2@web.de>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231019110724.15324-6-quintela@redhat.com>
2023-10-30 17:41:55 +01:00
Juan Quintela
83df387df7 migration: Make compress_data_with_multithreads return bool
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231019110724.15324-5-quintela@redhat.com>
2023-10-30 17:41:55 +01:00
Juan Quintela
4e400f9091 migration: Remove save_page_use_compression()
After previous patch, we disable the posiblity that we use compression
together with xbzrle.  So we can use directly migrate_compress().

Once there, now we don't need the rs parameter, so remove it.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231019110724.15324-4-quintela@redhat.com>
2023-10-30 17:41:55 +01:00
Juan Quintela
0e19562996 migration: Give one error if trying to set COMPRESSION and XBZRLE
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231019110724.15324-3-quintela@redhat.com>
2023-10-30 17:41:55 +01:00
Juan Quintela
d869f62975 migration: Give one error if trying to set MULTIFD and XBZRLE
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231019110724.15324-2-quintela@redhat.com>
2023-10-30 17:41:55 +01:00
Juan Quintela
7091dabeb4 migration: Rename ram_handle_compressed() to ram_handle_zero()
Now that we know it only handles zero, we can remove the ch parameter.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231019085259.13307-3-quintela@redhat.com>
2023-10-30 17:41:55 +01:00
Juan Quintela
413d64fedc migration: Receiving a zero page non zero is an error
We don't allow non zero compressed pages since:

commit 3edcd7e6eb
Author: Peter Lieven <pl@kamp.de>
Date:   Tue Mar 26 10:58:35 2013 +0100

    migration: search for zero instead of dup pages

RDMA case is a bit more complicated, but they don't handle it since:

commit a1febc4950
Author: Richard Henderson <rth@twiddle.net>
Date:   Mon Aug 29 11:46:14 2016 -0700

    cutils: Export only buffer_is_zero

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231019085259.13307-2-quintela@redhat.com>
2023-10-30 17:41:55 +01:00
Fabiano Rosas
175e63c982 migration/multifd: Stop checking p->quit in multifd_send_thread
We don't need to check p->quit in the multifd_send_thread() because it
is shadowed by the 'exiting' flag. Ever since that flag was added
p->quit became obsolete as a way to stop the thread.

Since p->quit is set at multifd_send_terminate_threads() under the
p->mutex lock, the thread will only see it once it loops, so 'exiting'
will always be seen first.

Note that setting p->quit at multifd_send_terminate_threads() still
makes sense because we need a way to inform multifd_send_pages() that
the channel has stopped.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231012140651.13122-3-farosas@suse.de>
2023-10-20 08:51:41 +02:00
Steve Sistare
d9cda21303 migration: simplify notifiers
Pass the callback function to add_migration_state_change_notifier so
that migration can initialize the notifier on add and clear it on
delete, which simplifies the call sites.  Shorten the function names
so the extra arg can be added more legibly.  Hide the global notifier
list in a new function migration_call_notifiers, and make it externally
visible so future live update code can call it.

No functional change.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Tested-by: Michael Galaxy <mgalaxy@akamai.com>
Reviewed-by: Michael Galaxy <mgalaxy@akamai.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <1686148954-250144-1-git-send-email-steven.sistare@oracle.com>
2023-10-20 08:51:41 +02:00
Peter Xu
2c36076a11 migration: Fix parse_ramblock() on overwritten retvals
It's possible that some errors can be overwritten with success retval later
on, and then ignored.  Always capture all errors and report.

Reported by Coverity 1522861, but actually I spot one more in the same
function.

Fixes: CID 1522861
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231017203855.298260-1-peterx@redhat.com>
2023-10-20 08:51:41 +02:00
Steve Sistare
c8a7fc5179 migration: simplify blockers
Modify migrate_add_blocker and migrate_del_blocker to take an Error **
reason.  This allows migration to own the Error object, so that if
an error occurs in migrate_add_blocker, migration code can free the Error
and clear the client handle, simplifying client code.  It also simplifies
the migrate_del_blocker call site.

In addition, this is a pre-requisite for a proposed future patch that would
add a mode argument to migration requests to support live update, and
maintain a list of blockers for each mode.  A blocker may apply to a single
mode or to multiple modes, and passing Error** will allow one Error object
to be registered for multiple modes.

No functional change.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Tested-by: Michael Galaxy <mgalaxy@akamai.com>
Reviewed-by: Michael Galaxy <mgalaxy@akamai.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <1697634216-84215-1-git-send-email-steven.sistare@oracle.com>
2023-10-20 08:51:41 +02:00
Juan Quintela
e8e4e7acd8 migration: save_zero_page() can take block through pss
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-10-18 10:39:03 +02:00
Juan Quintela
944853c201 migration: control_save_page() can take block through pss
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-10-18 10:39:03 +02:00
Juan Quintela
d637a182b9 migration: save_compress_page() can take block through pss
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-10-18 10:39:03 +02:00
Juan Quintela
17cd011d06 migration: Print block status when needed
The new line was only printed when command options were used.  When we
used migration parameters and capabilities, it wasn't.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231017172307.22858-2-quintela@redhat.com>
2023-10-17 22:14:51 +02:00
Juan Quintela
bef4e2ed8e migration: Use "i" as an for index in ram-compress.c
It is used everywhere else in C.  Once there, make sure that we don't
use the index outside of the for declaring the variable there.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
Message-ID: <20230613145757.10131-15-quintela@redhat.com>
2023-10-17 22:14:51 +02:00
Juan Quintela
4703d1958c migration: Simplify decompress_data_with_multi_threads()
Doing a break to do another break is just confused.  Just call return
when we know we want to return.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
Message-ID: <20230613145757.10131-14-quintela@redhat.com>
2023-10-17 22:14:51 +02:00
Juan Quintela
1fd03d41b8 migration: Move update_compress_threads_counts() to ram-compress.c
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
Message-ID: <20230613145757.10131-9-quintela@redhat.com>
2023-10-17 22:14:51 +02:00
Juan Quintela
f504789de5 migration: Create ram_compressed_pages()
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
Message-ID: <20230613145757.10131-8-quintela@redhat.com>
2023-10-17 22:14:51 +02:00
Juan Quintela
6f60900573 migration: Create populate_compress()
So we don't have to access compression_counters from outside
ram-compress.c.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
Message-ID: <20230613145757.10131-7-quintela@redhat.com>
2023-10-17 22:14:51 +02:00
Juan Quintela
809f188a1a migration: Move compression_counters cleanup ram-compress.c
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
Message-ID: <20230613145757.10131-6-quintela@redhat.com>
2023-10-17 22:14:51 +02:00
Juan Quintela
b88a3306fd migration: RDMA is not compatible with anything else
So give an error instead of just ignoring the other methods.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
Message-ID: <20230613145757.10131-4-quintela@redhat.com>
2023-10-17 22:14:51 +02:00
Fabiano Rosas
967e388987 migration/multifd: Clarify Error usage in multifd_channel_connect
The function is currently called from two sites, one always gives it a
NULL Error and the other always gives it a non-NULL Error.

In the non-NULL case, all it does it trace the error and return. One
of the callers already have tracing, add a tracepoint to the other and
stop passing the error into the function.

Cc: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231012134343.23757-4-farosas@suse.de>
2023-10-17 09:25:14 +02:00
Fabiano Rosas
ee8a7c9c46 migration/multifd: Unify multifd_send_thread error paths
The preferred usage of the Error type is to always set both the return
code and the error when a failure happens. As all code called from the
send thread follows this pattern, we'll always have the return code
and the error set at the same time.

Aside from the convention, in this piece of code this must be the
case, otherwise the if (ret != 0) would be exiting the thread without
calling multifd_send_terminate_threads() which is incorrect.

Unify both paths to make it clear that both are taken when there's an
error.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231012134343.23757-3-farosas@suse.de>
2023-10-17 09:25:14 +02:00
Fabiano Rosas
0e92f64448 migration/multifd: Remove direct "socket" references
We're about to enable support for other transports in multifd, so
remove direct references to sockets.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231012134343.23757-2-farosas@suse.de>
2023-10-17 09:25:14 +02:00
Fabiano Rosas
8697eb8577 migration/ram: Merge save_zero_page functions
We don't need to do this in two pieces. One single function makes it
easier to grasp, specially since it removes the indirection on the
return value handling.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011184604.32364-7-farosas@suse.de>
2023-10-17 09:25:14 +02:00
Fabiano Rosas
ccc09db87c migration/ram: Move xbzrle zero page handling into save_zero_page
It makes a bit more sense to have the zero page handling of xbzrle
right where we save the zero page.

Also invert the exit condition to remove one level of indentation
which makes the next patch easier to grasp.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011184604.32364-6-farosas@suse.de>
2023-10-17 09:25:14 +02:00
Fabiano Rosas
1e43f165d0 migration/ram: Stop passing QEMUFile around in save_zero_page
We don't need the QEMUFile when we're already passing the
PageSearchStatus.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011184604.32364-5-farosas@suse.de>
2023-10-17 09:25:14 +02:00
Fabiano Rosas
8f47d4ee43 migration/ram: Remove RAMState from xbzrle_cache_zero_page
'rs' is not used in that function. It's a leftover from commit
9360447d34 ("ram: Use MigrationStats for statistics").

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011184604.32364-4-farosas@suse.de>
2023-10-17 09:25:14 +02:00
Nikolay Borisov
2f5ced5b93 migration/ram: Refactor precopy ram loading code
Extract the ramblock parsing code into a routine that operates on the
sequence of headers from the stream and another the parses the
individual ramblock. This makes ram_load_precopy() easier to
comprehend.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011184604.32364-3-farosas@suse.de>
2023-10-17 09:25:14 +02:00
Elena Ufimtseva
1618f55221 multifd: reset next_packet_len after sending pages
Sometimes multifd sends just sync packet with no pages
(normal_num is 0). In this case the old value is being
preserved and being accounted for while only packet_len
is being transferred.
Reset it to 0 after sending and accounting for.

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011184358.97349-5-elena.ufimtseva@oracle.com>
2023-10-17 09:25:13 +02:00
Elena Ufimtseva
68b6e00048 multifd: fix counters in multifd_send_thread
Previous commit cbec7eb768
"migration/multifd: Compute transferred bytes correctly"
removed accounting for packet_len in non-rdma
case, but the next_packet_size only accounts for pages, not for
the header packet (normal_pages * PAGE_SIZE) that is being sent
as iov[0]. The packet_len part should be added to account for
the size of MultiFDPacket and the array of the offsets.

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011184358.97349-4-elena.ufimtseva@oracle.com>
2023-10-17 09:25:13 +02:00
Elena Ufimtseva
60c7981aa3 migration: check for rate_limit_max for RATE_LIMIT_DISABLED
In migration rate limiting atomic operations are used
to read the rate limit variables and transferred bytes and
they are expensive. Check first if rate_limit_max is equal
to RATE_LIMIT_DISABLED and return false immediately if so.

Note that with this patch we will also will stop flushing
by not calling qemu_fflush() from migration_transferred_bytes()
if the migration rate is not exceeded.
This should be fine since migration thread calls in the loop
migration_update_counters from migration_rate_limit() that
calls the migration_transferred_bytes() and flushes there.

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011184358.97349-2-elena.ufimtseva@oracle.com>
2023-10-17 09:25:13 +02:00
Juan Quintela
8f5a7faa4e migration/rdma: Remove all "ret" variables that are used only once
Change code that is:

int ret;
...

ret = foo();
if (ret[ < 0]?) {

to:

if (foo()[ < 0]) {

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011203527.9061-14-quintela@redhat.com>
2023-10-17 09:25:13 +02:00
Juan Quintela
14e2fcbbf8 migration/rdma: Declare for index variables local
Declare all variables that are only used inside a for loop inside the
for statement.

This makes clear that they are not used outside of the for loop.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011203527.9061-13-quintela@redhat.com>
2023-10-17 09:25:13 +02:00
Juan Quintela
ebdb85f9d1 migration/rdma: Use i as for index instead of idx
Once there, all the uses are local to the for, so declare the variable
inside the for statement.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011203527.9061-12-quintela@redhat.com>
2023-10-17 09:25:13 +02:00
Juan Quintela
a4832d299d migration/rdma: Check sooner if we are in postcopy for save_page()
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011203527.9061-11-quintela@redhat.com>
2023-10-17 09:25:13 +02:00
Juan Quintela
b1b3838722 migration/rdma: Remove qemu_ prefix from exported functions
Functions are long enough even without this.

Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011203527.9061-10-quintela@redhat.com>
2023-10-17 09:25:13 +02:00
Juan Quintela
10cb3336b1 migration/rdma: Move rdma constants from qemu-file.h to rdma.h
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011203527.9061-9-quintela@redhat.com>
2023-10-17 09:25:13 +02:00
Juan Quintela
8b670f48ed qemu-file: Remove QEMUFileHooks
The only user was rdma, and its use is gone.

Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011203527.9061-8-quintela@redhat.com>
2023-10-17 09:25:13 +02:00
Juan Quintela
e493008d50 migration/rdma: Create rdma_control_save_page()
The only user of ram_control_save_page() and save_page() hook was
rdma. Just move the function to rdma.c, rename it to
rdma_control_save_page().

Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011203527.9061-7-quintela@redhat.com>
2023-10-17 09:25:13 +02:00
Juan Quintela
a6323300e8 migration/rdma: Unfold hook_ram_load()
There is only one flag called with: RAM_CONTROL_BLOCK_REG.

Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011203527.9061-6-quintela@redhat.com>
2023-10-17 09:25:13 +02:00
Juan Quintela
f6d6c089b7 migration/rdma: Remove all uses of RAM_CONTROL_HOOK
Instead of going through ram_control_load_hook(), call
qemu_rdma_registration_handle() directly.

Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011203527.9061-5-quintela@redhat.com>
2023-10-17 09:25:13 +02:00
Juan Quintela
5f5b8858dc migration/rdma: Unfold ram_control_after_iterate()
Once there:
- Remove unused data parameter
- unfold it in its callers
- change all callers to call qemu_rdma_registration_stop()
- We need to call QIO_CHANNEL_RDMA() after we check for migrate_rdma()

Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011203527.9061-4-quintela@redhat.com>
2023-10-17 09:25:13 +02:00
Juan Quintela
48408174a7 migration/rdma: Unfold ram_control_before_iterate()
Once there:
- Remove unused data parameter
- unfold it in its callers.
- change all callers to call qemu_rdma_registration_start()
- We need to call QIO_CHANNEL_RDMA() after we check for migrate_rdma()

Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011203527.9061-3-quintela@redhat.com>
2023-10-17 09:25:13 +02:00
Juan Quintela
27fd25b0fb migration: Create migrate_rdma()
Helper to say if we are doing a migration over rdma.

Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011203527.9061-2-quintela@redhat.com>
2023-10-17 09:25:13 +02:00
Juan Quintela
d4f34485ca migration: Non multifd migration don't care about multifd flushes
RDMA was having trouble because
migrate_multifd_flush_after_each_section() can only be true or false,
but we don't want to send any flush when we are not in multifd
migration.

CC: Fabiano Rosas <farosas@suse.de
Fixes: 294e5a4034 ("multifd: Only flush once each full round of memory")

Reported-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011205548.10571-2-quintela@redhat.com>
2023-10-17 09:25:13 +02:00
Fiona Ebner
930e239d11 migration: hold the BQL during setup
This is intended to be a semantic revert of commit 9b09503752
("migration: run setup callbacks out of big lock"). There have been so
many changes since that commit (e.g. a new setup callback
dirty_bitmap_save_setup() that also needs to be adapted now), it's
easier to do the revert manually.

For snapshots, the bdrv_writev_vmstate() function is used during setup
(in QIOChannelBlock backing the QEMUFile), but not holding the BQL
while calling it could lead to an assertion failure. To understand
how, first note the following:

1. Generated coroutine wrappers for block layer functions spawn the
coroutine and use AIO_WAIT_WHILE()/aio_poll() to wait for it.
2. If the host OS switches threads at an inconvenient time, it can
happen that a bottom half scheduled for the main thread's AioContext
is executed as part of a vCPU thread's aio_poll().

An example leading to the assertion failure is as follows:

main thread:
1. A snapshot-save QMP command gets issued.
2. snapshot_save_job_bh() is scheduled.

vCPU thread:
3. aio_poll() for the main thread's AioContext is called (e.g. when
the guest writes to a pflash device, as part of blk_pwrite which is a
generated coroutine wrapper).
4. snapshot_save_job_bh() is executed as part of aio_poll().
3. qemu_savevm_state() is called.
4. qemu_mutex_unlock_iothread() is called. Now
qemu_get_current_aio_context() returns 0x0.
5. bdrv_writev_vmstate() is executed during the usual savevm setup
via qemu_fflush(). But this function is a generated coroutine wrapper,
so it uses AIO_WAIT_WHILE. There, the assertion
assert(qemu_get_current_aio_context() == qemu_get_aio_context());
will fail.

To fix it, ensure that the BQL is held during setup. While it would
only be needed for snapshots, adapting migration too avoids additional
logic for conditional locking/unlocking in the setup callbacks.
Writing the header could (in theory) also trigger qemu_fflush() and
thus bdrv_writev_vmstate(), so the locked section also covers the
qemu_savevm_state_header() call, even for migration for consistency.

The section around multifd_send_sync_main() needs to be unlocked to
avoid a deadlock. In particular, the multifd_save_setup() function calls
socket_send_channel_create() using multifd_new_send_channel_async() as a
callback and then waits for the callback to signal via the
channels_ready semaphore. The connection happens via
qio_task_run_in_thread(), but the callback is only executed via
qio_task_thread_result() which is scheduled for the main event loop.
Without unlocking the section, the main thread would never get to
process the task result and the callback meaning there would be no
signal via the channels_ready semaphore.

The comment in ram_init_bitmaps() was introduced by 4987783400
("migration: fix incorrect memory_global_dirty_log_start outside BQL")
and is removed, because it referred to the qemu_mutex_lock_iothread()
call.

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231013105839.415989-1-f.ebner@proxmox.com>
2023-10-17 09:25:13 +02:00
Nikolay Borisov
2aae1eb8da migration: Add the configuration vmstate to the json writer
Make the migration json writer part of MigrationState struct, allowing
the 'configuration' object be serialized to json.

This will facilitate the parsing of the 'configuration' object in the
next patch that fixes analyze-migration.py for arm.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231009184326.15777-2-farosas@suse.de>
2023-10-17 09:14:32 +02:00
Dmitry Frolov
f75ed59f40 migration: fix RAMBlock add NULL check
qemu_ram_block_from_host() may return NULL, which will be dereferenced w/o
check. Usualy return value is checked for this function.
Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Dmitry Frolov <frolov@swemel.ru>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231010104851.802947-1-frolov@swemel.ru>
2023-10-17 09:14:32 +02:00
Peter Xu
8b2395970a migration: Allow user to specify available switchover bandwidth
Migration bandwidth is a very important value to live migration.  It's
because it's one of the major factors that we'll make decision on when to
switchover to destination in a precopy process.

This value is currently estimated by QEMU during the whole live migration
process by monitoring how fast we were sending the data.  This can be the
most accurate bandwidth if in the ideal world, where we're always feeding
unlimited data to the migration channel, and then it'll be limited to the
bandwidth that is available.

However in reality it may be very different, e.g., over a 10Gbps network we
can see query-migrate showing migration bandwidth of only a few tens of
MB/s just because there are plenty of other things the migration thread
might be doing.  For example, the migration thread can be busy scanning
zero pages, or it can be fetching dirty bitmap from other external dirty
sources (like vhost or KVM).  It means we may not be pushing data as much
as possible to migration channel, so the bandwidth estimated from "how many
data we sent in the channel" can be dramatically inaccurate sometimes.

With that, the decision to switchover will be affected, by assuming that we
may not be able to switchover at all with such a low bandwidth, but in
reality we can.

The migration may not even converge at all with the downtime specified,
with that wrong estimation of bandwidth, keeping iterations forever with a
low estimation of bandwidth.

The issue is QEMU itself may not be able to avoid those uncertainties on
measuing the real "available migration bandwidth".  At least not something
I can think of so far.

One way to fix this is when the user is fully aware of the available
bandwidth, then we can allow the user to help providing an accurate value.

For example, if the user has a dedicated channel of 10Gbps for migration
for this specific VM, the user can specify this bandwidth so QEMU can
always do the calculation based on this fact, trusting the user as long as
specified.  It may not be the exact bandwidth when switching over (in which
case qemu will push migration data as fast as possible), but much better
than QEMU trying to wildly guess, especially when very wrong.

A new parameter "avail-switchover-bandwidth" is introduced just for this.
So when the user specified this parameter, instead of trusting the
estimated value from QEMU itself (based on the QEMUFile send speed), it
trusts the user more by using this value to decide when to switchover,
assuming that we'll have such bandwidth available then.

Note that specifying this value will not throttle the bandwidth for
switchover yet, so QEMU will always use the full bandwidth possible for
sending switchover data, assuming that should always be the most important
way to use the network at that time.

This can resolve issues like "unconvergence migration" which is caused by
hilarious low "migration bandwidth" detected for whatever reason.

Reported-by: Zhiyi Guo <zhguo@redhat.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231010221922.40638-1-peterx@redhat.com>
2023-10-17 09:14:32 +02:00
Philippe Mathieu-Daudé
1a36e4c9d0 migration: Use g_autofree to simplify ram_dirty_bitmap_reload()
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231011023627.86691-1-philmd@linaro.org>
2023-10-17 09:14:32 +02:00
Wei Wang
d7f5a04320 migration: refactor migration_completion
Current migration_completion function is a bit long. Refactor the long
implementation into different subfunctions:
- migration_completion_precopy: completion code related to precopy
- migration_completion_postcopy: completion code related to postcopy

Rename await_return_path_close_on_source to
close_return_path_on_source: It is renamed to match with
open_return_path_on_source.

This improves readability and is easier for future updates (e.g. add new
subfunctions when completion code related to new features are needed). No
functional changes intended.

Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230804093053.5037-1-wei.w.wang@intel.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-10-17 09:14:32 +02:00
Kevin Wolf
2b3912f135 block: Mark bdrv_first_blk() and bdrv_is_root_node() GRAPH_RDLOCK
This adds GRAPH_RDLOCK annotations to declare that callers of
bdrv_first_blk() and bdrv_is_root_node() need to hold a reader lock
for the graph. These functions are the only functions in block-backend.c
that access the parent list of a node.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20230929145157.45443-5-kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-10-12 16:31:33 +02:00
Peter Xu
5e79a4bf03 migration: Add migration_rp_wait|kick()
It's just a simple wrapper for rp_sem on either wait() or kick(), make it
even clearer on how it is used.  Prepared to be used even for other things.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-ID: <20231004220240.167175-8-peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-10-11 11:17:05 +02:00
Peter Xu
1015ff5476 migration: Remember num of ramblocks to sync during recovery
Instead of only relying on the count of rp_sem, make the counter be part of
RAMState so it can be used in both threads to synchronize on the process.

rp_sem will be further reused in follow up patches, as a way to kick the
main thread, e.g., on recovery failures.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231004220240.167175-7-peterx@redhat.com>
2023-10-11 11:17:05 +02:00
Peter Xu
f4b897f485 qemufile: Always return a verbose error
There're a lot of cases where we only have an errno set in last_error but
without a detailed error description.  When this happens, try to generate
an error contains the errno as a descriptive error.

This will be helpful in cases where one relies on the Error*.  E.g.,
migration state only caches Error* in MigrationState.error.  With this,
we'll display correct error messages in e.g. query-migrate when the error
was only set by qemu_file_set_error().

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231004220240.167175-6-peterx@redhat.com>
2023-10-11 11:17:05 +02:00
Peter Xu
2b2f6f411e migration: Introduce migrate_has_error()
Introduce a helper to detect whether MigrationState.error is set for
whatever reason.

This is preparation work for any thread (e.g. source return path thread) to
setup errors in an unified way to MigrationState, rather than relying on
its own way to set errors (mark_source_rp_bad()).

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231004220240.167175-3-peterx@redhat.com>
2023-10-11 11:17:05 +02:00
Peter Xu
c94143e587 migration: Display error in query-migrate irrelevant of status
Display it as long as being set, irrelevant of FAILED status.  E.g., it may
also be applicable to PAUSED stage of postcopy, to provide hint on what has
gone wrong.

The error_mutex seems to be overlooked when referencing the error, add it
to be very safe.

This will change QAPI behavior by showing up error message outside !FAILED
status, but it's intended and doesn't expect to break anyone.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2018404
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231004220240.167175-2-peterx@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
2c88739cfd migration/rdma: Replace flawed device detail dump by tracing
qemu_rdma_dump_id() dumps RDMA device details to stdout.

rdma_start_outgoing_migration() calls it via qemu_rdma_source_init()
and qemu_rdma_resolve_host() to show source device details.
rdma_start_incoming_migration() arranges its call via
rdma_accept_incoming_migration() and qemu_rdma_accept() to show
destination device details.

Two issues:

1. rdma_start_outgoing_migration() can run in HMP context.  The
   information should arguably go the monitor, not stdout.

2. ibv_query_port() failure is reported as error.  Its callers remain
   unaware of this failure (qemu_rdma_dump_id() can't fail), so
   reporting this to the user as an error is problematic.

Fixable, but the device detail dump is noise, except when
troubleshooting.  Tracing is a better fit.  Similar function
qemu_rdma_dump_id() was converted to tracing in commit
733252deb8 (Tracify migration/rdma.c).

Convert qemu_rdma_dump_id(), too.

While there, touch up qemu_rdma_dump_gid()'s outdated comment.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-54-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
ff4c919459 migration/rdma: Use error_report() & friends instead of stderr
error_report() obeys -msg, reports the current error location if any,
and reports to the current monitor if any.  Reporting to stderr
directly with fprintf() or perror() is wrong, because it loses all
this.

Fix the offenders.  Bonus: resolves a FIXME about problematic use of
errno.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-53-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
5cec563d0c migration/rdma: Downgrade qemu_rdma_cleanup() errors to warnings
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_source_init(), qemu_rdma_connect(),
rdma_start_incoming_migration(), and rdma_start_outgoing_migration()
violate this principle: they call error_report() via
qemu_rdma_cleanup().

Moreover, qemu_rdma_cleanup() can't fail.  It is called on error
paths, and QIOChannel close and finalization.  Are the conditions it
reports really errors?  I doubt it.

Downgrade qemu_rdma_cleanup()'s errors to warnings.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-52-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
b765d21e4a migration/rdma: Silence qemu_rdma_register_and_get_keys()
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_write_one() violates this principle: it reports errors to
stderr via qemu_rdma_register_and_get_keys().  I elected not to
investigate how callers handle the error, i.e. precise impact is not
known.

Clean this up: silence qemu_rdma_register_and_get_keys().  I believe
the caller's error reports suffice.  If they don't, we need to convert
to Error instead.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-51-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
7555c7713d migration/rdma: Silence qemu_rdma_block_for_wrid()
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_post_send_control(), qemu_rdma_exchange_get_response(), and
qemu_rdma_write_one() violate this principle: they call
error_report(), fprintf(stderr, ...), and perror() via
qemu_rdma_block_for_wrid(), qemu_rdma_poll(), and
qemu_rdma_wait_comp_channel().  I elected not to investigate how
callers handle the error, i.e. precise impact is not known.

Clean this up by dropping the error reporting from qemu_rdma_poll(),
qemu_rdma_wait_comp_channel(), and qemu_rdma_block_for_wrid().  I
believe the callers' error reports suffice.  If they don't, we need to
convert to Error instead.

Bonus: resolves a FIXME about problematic use of errno.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-50-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
8dee156c1d migration/rdma: Don't report received completion events as error
When qemu_rdma_wait_comp_channel() receives an event from the
completion channel, it reports an error "receive cm event while wait
comp channel,cm event is T", where T is the numeric event type.
However, the function fails only when T is a disconnect or device
removal.  Events other than these two are not actually an error, and
reporting them as an error is wrong.  If we need to report them to the
user, we should use something else, and what to use depends on why we
need to report them to the user.

For now, report this error only when the function actually fails.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-49-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
01efb10637 migration/rdma: Silence qemu_rdma_reg_control()
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_source_init() and qemu_rdma_accept() violate this principle:
they call error_report() via qemu_rdma_reg_control().  I elected not
to investigate how callers handle the error, i.e. precise impact is
not known.

Clean this up by dropping the error reporting from
qemu_rdma_reg_control().  I believe the callers' error reports
suffice.  If they don't, we need to convert to Error instead.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-48-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
35b1561e3e migration/rdma: Silence qemu_rdma_connect()
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_connect() violates this principle: it calls error_report()
and perror().  I elected not to investigate how callers handle the
error, i.e. precise impact is not known.

Clean this up: replace perror() by changing error_setg() to
error_setg_errno(), and drop error_report().  I believe the callers'
error reports suffice then.  If they don't, we need to convert to
Error instead.

Bonus: resolves a FIXME about problematic use of errno.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-47-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
e6696d3ee9 migration/rdma: Silence qemu_rdma_resolve_host()
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_resolve_host() violates this principle: it calls
error_report().

Clean this up: drop error_report().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-46-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
07d5b94653 migration/rdma: Convert qemu_rdma_alloc_pd_cq() to Error
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_source_init() violates this principle: it calls
error_report() via qemu_rdma_alloc_pd_cq().  I elected not to
investigate how callers handle the error, i.e. precise impact is not
known.

Clean this up by converting qemu_rdma_alloc_pd_cq() to Error.

The conversion loses a piece of advice on one of two failure paths:

    Your mlock() limits may be too low. Please check $ ulimit -a # and search for 'ulimit -l' in the output

Not worth retaining.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-45-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
3c0c3eba8d migration/rdma: Convert qemu_rdma_post_recv_control() to Error
Just for symmetry with qemu_rdma_post_send_control().  Error messages
lose detail I consider of no use to users.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-44-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
f3805964f8 migration/rdma: Convert qemu_rdma_post_send_control() to Error
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_exchange_send() violates this principle: it calls
error_report() via qemu_rdma_post_send_control().  I elected not to
investigate how callers handle the error, i.e. precise impact is not
known.

Clean this up by converting qemu_rdma_post_send_control() to Error.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-43-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
446e559c43 migration/rdma: Convert qemu_rdma_write() to Error
Just for consistency with qemu_rdma_write_one() and
qemu_rdma_write_flush(), and for slightly simpler code.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-42-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
557c34ca60 migration/rdma: Convert qemu_rdma_write_one() to Error
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_write_flush() violates this principle: it calls
error_report() via qemu_rdma_write_one().  I elected not to
investigate how callers handle the error, i.e. precise impact is not
known.

Clean this up by converting qemu_rdma_write_one() to Error.  Bonus:
resolves a FIXME about problematic use of errno.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-41-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
5609547781 migration/rdma: Convert qemu_rdma_write_flush() to Error
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qio_channel_rdma_writev() violates this principle: it calls
error_report() via qemu_rdma_write_flush().  I elected not to
investigate how callers handle the error, i.e. precise impact is not
known.

Clean this up by converting qemu_rdma_write_flush() to Error.

Necessitates setting an error when qemu_rdma_write_one() failed.
Since this error will go away later in this series, simply use "FIXME
temporary error message" there.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-40-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
de1aa35f8d migration/rdma: Convert qemu_rdma_reg_whole_ram_blocks() to Error
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_exchange_send() violates this principle: it calls
error_report() via callback qemu_rdma_reg_whole_ram_blocks().  I
elected not to investigate how callers handle the error, i.e. precise
impact is not known.

Clean this up by converting the callback to Error.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-39-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
3765ec1f43 migration/rdma: Convert qemu_rdma_exchange_get_response() to Error
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qemu_rdma_exchange_send() and qemu_rdma_exchange_recv() violate this
principle: they call error_report() via
qemu_rdma_exchange_get_response().  I elected not to investigate how
callers handle the error, i.e. precise impact is not known.

Clean this up by converting qemu_rdma_exchange_get_response() to
Error.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-38-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
c4c78dce0b migration/rdma: Convert qemu_rdma_exchange_send() to Error
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qio_channel_rdma_writev() violates this principle: it calls
error_report() via qemu_rdma_exchange_send().  I elected not to
investigate how callers handle the error, i.e. precise impact is not
known.

Clean this up by converting qemu_rdma_exchange_send() to Error.

Necessitates setting an error when qemu_rdma_post_recv_control(),
callback(), or qemu_rdma_exchange_get_response() failed.  Since these
errors will go away later in this series, simply use "FIXME temporary
error message" there.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-37-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
96f363d839 migration/rdma: Convert qemu_rdma_exchange_recv() to Error
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

qio_channel_rdma_readv() violates this principle: it calls
error_report() via qemu_rdma_exchange_recv().  I elected not to
investigate how callers handle the error, i.e. precise impact is not
known.

Clean this up by converting qemu_rdma_exchange_recv() to Error.

Necessitates setting an error when qemu_rdma_exchange_get_response()
failed.  Since this error will go away later in this series, simply
use "FIXME temporary error message" there.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-36-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
dcf07e72a4 migration/rdma: Drop "@errp is clear" guards around error_setg()
These guards are all redundant now.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-35-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
071d5ae4f3 migration/rdma: Fix error handling around rdma_getaddrinfo()
qemu_rdma_resolve_host() and qemu_rdma_dest_init() iterate over
addresses to find one that works, holding onto the first Error from
qemu_rdma_broken_ipv6_kernel() for use when no address works.  Issues:

1. If @errp was &error_abort or &error_fatal, we'd terminate instead
   of trying the next address.  Can't actually happen, since no caller
   passes these arguments.

2. When @errp is a pointer to a variable containing NULL, and
   qemu_rdma_broken_ipv6_kernel() fails, the variable no longer
   contains NULL.  Subsequent iterations pass it again, violating
   Error usage rules.  Dangerous, as setting an error would then trip
   error_setv()'s assertion.  Works only because
   qemu_rdma_broken_ipv6_kernel() and the code following the loops
   carefully avoids setting a second error.

3. If qemu_rdma_broken_ipv6_kernel() fails, and then a later iteration
   finds a working address, @errp still holds the first error from
   qemu_rdma_broken_ipv6_kernel().  If we then run into another error,
   we report the qemu_rdma_broken_ipv6_kernel() failure instead.

4. If we don't run into another error, we leak the Error object.

Use a local error variable, and propagate to @errp.  This fixes 3. and
also cleans up 1 and partly 2.

Free this error when we have a working address.  This fixes 4.

Pass the local error variable to qemu_rdma_broken_ipv6_kernel() only
until it fails.  Pass null on any later iterations.  This cleans up
the remainder of 2.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-34-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
8fd471bd77 migration/rdma: Retire macro ERROR()
ERROR() has become "error_setg() unless an error has been set
already".  Hiding the conditional in the macro is in the way of
further work.  Replace the macro uses by their expansion, and delete
the macro.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-33-armbru@redhat.com>
2023-10-11 11:17:04 +02:00
Markus Armbruster
1718f238d1 migration/rdma: Delete inappropriate error_report() in macro ERROR()
Functions that use an Error **errp parameter to return errors should
not also report them to the user, because reporting is the caller's
job.  When the caller does, the error is reported twice.  When it
doesn't (because it recovered from the error), there is no error to
report, i.e. the report is bogus.

Macro ERROR() violates this principle.  Delete the error_report()
there.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Tested-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-32-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
e518b0050d migration/rdma: Plug a memory leak and improve a message
When migration capability @rdma-pin-all is true, but the server cannot
honor it, qemu_rdma_connect() calls macro ERROR(), then returns
success.

ERROR() sets an error.  Since qemu_rdma_connect() returns success, its
caller rdma_start_outgoing_migration() duly assumes @errp is still
clear.  The Error object leaks.

ERROR() additionally reports the situation to the user as an error:

    RDMA ERROR: Server cannot support pinning all memory. Will register memory dynamically.

Is this an error or not?  It actually isn't; we disable @rdma-pin-all
and carry on.  "Correcting" the user's configuration decisions that
way feels problematic, but that's a topic for another day.

Replace ERROR() by warn_report().  This plugs the memory leak, and
emits a clearer message to the user.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-31-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
4a10217962 migration/rdma: Check negative error values the same way everywhere
When a function returns 0 on success, negative value on error,
checking for non-zero suffices, but checking for negative is clearer.
So do that.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-30-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
c0d77702d2 migration/rdma: Drop superfluous assignments to @ret
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-29-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
b86c94a49e migration/rdma: Replace int error_state by bool errored
All we do with the value of RDMAContext member @error_state is test
whether it's zero.  Change to bool and rename to @errored.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-28-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
ec48697453 migration/rdma: Dumb down remaining int error values to -1
This is just to make the error value more obvious.  Callers don't
mind.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-27-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
8c6513f750 migration/rdma: Return -1 instead of negative errno code
Several functions return negative errno codes on failure.  Callers
check for specific codes exactly never.  For some of the functions,
callers couldn't check even if they wanted to, because the functions
also return negative values that aren't errno codes, leaving readers
confused on what the function actually returns.

Clean up and simplify: return -1 instead of negative errno code.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-26-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
0724982221 migration/rdma: Fix rdma_getaddrinfo() error checking
rdma_getaddrinfo() returns 0 on success.  On error, it returns one of
the EAI_ error codes like getaddrinfo() does, or -1 with errno set.
This is broken by design: POSIX implicitly specifies the EAI_ error
codes to be non-zero, no more.  They could clash with -1.  Nothing we
can do about this design flaw.

Both callers of rdma_getaddrinfo() only recognize negative values as
error.  Works only because systems elect to make the EAI_ error codes
negative.

Best not to rely on that: change the callers to treat any non-zero
value as failure.  Also change them to return -1 instead of the value
received from getaddrinfo() on failure, to avoid positive error
values.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-25-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
0110c6b86a migration/rdma: Fix QEMUFileHooks method return values
The QEMUFileHooks methods don't come with a written contract.  Digging
through the code calling them, we find:

* save_page():

  Negative values RAM_SAVE_CONTROL_DELAYED and
  RAM_SAVE_CONTROL_NOT_SUPP are special.  Any other negative value is
  an unspecified error.

  qemu_rdma_save_page() returns -EIO or rdma->error_state on error.  I
  believe the latter is always negative.  Nothing stops either of them
  to clash with the special values, though.  Feels unlikely, but fix
  it anyway to return only the special values and -1.

* before_ram_iterate(), after_ram_iterate():

  Negative value means error.  qemu_rdma_registration_start() and
  qemu_rdma_registration_stop() comply as far as I can tell.  Make
  them comply *obviously*, by returning -1 on error.

* hook_ram_load:

  Negative value means error.  rdma_load_hook() already returns -1 on
  error.  Leave it alone.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-24-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
d63f4016b1 migration/rdma: Drop dead qemu_rdma_data_init() code for !@host_port
qemu_rdma_data_init() neglects to set an Error when it fails because
@host_port is null.  Fortunately, no caller passes null, so this is
merely a latent bug.  Drop the flawed code handling null argument.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-23-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
f35c0d9b07 migration/rdma: Fix qemu_get_cm_event_timeout() to always set error
qemu_get_cm_event_timeout() neglects to set an error when it fails
because rdma_get_cm_event() fails.  Harmless, as its caller
qemu_rdma_connect() substitutes a generic error then.  Fix it anyway.

qemu_rdma_connect() also sets the generic error when its own call of
rdma_get_cm_event() fails.  Make the error handling more obvious: set
a specific error right after rdma_get_cm_event() fails.  Delete the
generic error.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-22-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
142bd685ae migration/rdma: Fix qemu_rdma_broken_ipv6_kernel() to set error
qemu_rdma_resolve_host() and qemu_rdma_dest_init() try addresses until
they find on that works.  If none works, they return the first Error
set by qemu_rdma_broken_ipv6_kernel(), or else return a generic one.

qemu_rdma_broken_ipv6_kernel() neglects to set an Error when
ibv_open_device() fails.  If a later address fails differently, we use
that Error instead, or else the generic one.  Harmless enough, but
needs fixing all the same.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-21-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
de3e05e8b9 migration/rdma: Replace dangerous macro CHECK_ERROR_STATE()
Hiding return statements in macros is a bad idea.  Use a function
instead, and open code the return part.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-20-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
8e262e0b3d migration/rdma: Fix io_writev(), io_readv() methods to obey contract
QIOChannelClass methods qio_channel_rdma_readv() and
qio_channel_rdma_writev() violate their method contract when
rdma->error_state is non-zero:

1. They return whatever is in rdma->error_state then.  Only -1 will be
   fine.  -2 will be misinterpreted as "would block".  Anything less
   than -2 isn't defined in the contract.  A positive value would be
   misinterpreted as success, but I believe that's not actually
   possible.

2. They neglect to set an error then.  If something up the call stack
   dereferences the error when failure is returned, it will crash.  If
   it ignores the return value and checks the error instead, it will
   miss the error.

Crap like this happens when return statements hide in macros,
especially when their uses are far away from the definition.

I elected not to investigate how callers are impacted.

Expand the two bad macro uses, so we can set an error and return -1.
The next commit will then get rid of the macro altogether.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-19-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
1b6e1da6e7 migration/rdma: Ditch useless numeric error codes in error messages
Several error messages include numeric error codes returned by failed
functions:

* ibv_poll_cq() returns an unspecified negative value.  Useless.

* rdma_accept and rdma_get_cm_event() return -1.  Useless.

* qemu_rdma_poll() returns either -1 or an unspecified negative
  value.  Useless.

* qemu_rdma_block_for_wrid(), qemu_rdma_write_flush(),
  qemu_rdma_exchange_send(), qemu_rdma_exchange_recv(),
  qemu_rdma_write() return a negative value that may or may not be an
  errno value.  While reporting human-readable errno
  information (which a number is not) can be useful, reporting an
  error code that may or may not be an errno value is useless.

Drop these error codes from the error messages.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-18-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
0bc2604508 migration/rdma: Fix or document problematic uses of errno
We use errno after calling Libibverbs functions that are not
documented to set errno (manual page does not mention errno), or where
the documentation is unclear ("returns [...] the value of errno on
failure").  While this could be read as "sets errno and returns it",
a glance at the source code[*] kills that hope:

    static inline int ibv_post_send(struct ibv_qp *qp, struct ibv_send_wr *wr,
                                    struct ibv_send_wr **bad_wr)
    {
            return qp->context->ops.post_send(qp, wr, bad_wr);
    }

The callback can be

    static int mana_post_send(struct ibv_qp *ibqp, struct ibv_send_wr *wr,
                              struct ibv_send_wr **bad)
    {
            /* This version of driver supports RAW QP only.
             * Posting WR is done directly in the application.
             */
            return EOPNOTSUPP;
    }

Neither of them touches errno.

One of these errno uses is easy to fix, so do that now.  Several more
will go away later in the series; add temporary FIXME commments.
Three will remain; add TODO comments.  TODO, not FIXME, because the
bug might be in Libibverbs documentation.

[*] https://github.com/linux-rdma/rdma-core.git
    commit 55fa316b4b18f258d8ac1ceb4aa5a7a35b094dcf

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-17-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
89997ac318 migration/rdma: Use bool for two RDMAContext flags
@error_reported and @received_error are flags.  The latter is even
assigned bool true.  Change them from int to bool.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-16-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
6a3792d78d migration/rdma: Make qemu_rdma_buffer_mergeable() return bool
qemu_rdma_buffer_mergeable() is semantically a predicate.  It returns
int 0 or 1.  Return bool instead, and fix the function name's
spelling.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-15-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
87e6bdabf0 migration/rdma: Drop qemu_rdma_search_ram_block() error handling
qemu_rdma_search_ram_block() can't fail.  Return void, and drop the
unreachable error handling.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-14-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
0610d7a1d8 migration/rdma: Drop rdma_add_block() error handling
rdma_add_block() can't fail.  Return void, and drop the unreachable
error handling.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-13-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
b16defbbfe migration/rdma: Eliminate error_propagate()
When all we do with an Error we receive into a local variable is
propagating to somewhere else, we can just as well receive it there
right away.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-12-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
3c03f21cb5 migration/rdma: Put @errp parameter last
include/qapi/error.h demands:

 * - Functions that use Error to report errors have an Error **errp
 *   parameter.  It should be the last parameter, except for functions
 *   taking variable arguments.

qemu_rdma_connect() does not conform.  Clean it up.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-11-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
9a6afb1170 migration/rdma: Fix qemu_rdma_accept() to return failure on errors
qemu_rdma_accept() returns 0 in some cases even when it didn't
complete its job due to errors.  Impact is not obvious.  I figure the
caller will soon fail again with a misleading error message.

Fix it to return -1 on any failure.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-10-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
36cc822d85 migration/rdma: Give qio_channel_rdma_source_funcs internal linkage
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-9-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
8ff58b05a3 migration/rdma: Clean up two more harmless signed vs. unsigned issues
qemu_rdma_exchange_get_response() compares int parameter @expecting
with uint32_t head->type.  Actual arguments are non-negative
enumeration constants, RDMAControlHeader uint32_t member type, or
qemu_rdma_exchange_recv() int parameter expecting.  Actual arguments
for the latter are non-negative enumeration constants.  Change both
parameters to uint32_t.

In qio_channel_rdma_readv(), loop control variable @i is ssize_t, and
counts from 0 up to @niov, which is size_t.  Change @i to size_t.

While there, make qio_channel_rdma_readv() and
qio_channel_rdma_writev() more consistent: change the former's @done
to ssize_t, and delete the latter's useless initialization of @len.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-8-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
25352b371b migration/rdma: Fix unwanted integer truncation
qio_channel_rdma_readv() assigns the size_t value of qemu_rdma_fill()
to an int variable before it adds it to @done / subtracts it from
@want, both size_t.  Truncation when qemu_rdma_fill() copies more than
INT_MAX bytes.  Seems vanishingly unlikely, but needs fixing all the
same.

Fixes: 6ddd2d76ca (migration: convert RDMA to use QIOChannel interface)
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-7-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
87a24ca3f2 migration/rdma: Consistently use uint64_t for work request IDs
We use int instead of uint64_t in a few places.  Change them to
uint64_t.

This cleans up a comparison of signed qemu_rdma_block_for_wrid()
parameter @wrid_requested with unsigned @wr_id.  Harmless, because the
actual arguments are non-negative enumeration constants.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-6-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
b5631d5bda migration/rdma: Drop fragile wr_id formatting
wrid_desc[] uses 4001 pointers to map four integer values to strings.

print_wrid() accesses wrid_desc[] out of bounds when passed a negative
argument.  It returns null for values 2..1999 and 2001..3999.

qemu_rdma_poll() and qemu_rdma_block_for_wrid() print wrid_desc[wr_id]
and passes print_wrid(wr_id) to tracepoints.  Could conceivably crash
trying to format a null string.  I believe access out of bounds is not
possible.

Not worth cleaning up.  Dumb down to show just numeric wr_id.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-5-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
1720a2a875 migration/rdma: Clean up rdma_delete_block()'s return type
rdma_delete_block() always returns 0, which its only caller ignores.
Return void instead.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-4-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
c07d19622c migration/rdma: Clean up qemu_rdma_data_init()'s return type
qemu_rdma_data_init() return type is void *.  It actually returns
RDMAContext *, and all its callers assign the value to an
RDMAContext *.  Unclean.

Return RDMAContext * instead.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-3-armbru@redhat.com>
2023-10-11 11:17:03 +02:00
Markus Armbruster
b72eacf3c0 migration/rdma: Clean up qemu_rdma_poll()'s return type
qemu_rdma_poll()'s return type is uint64_t, even though it returns 0,
-1, or @ret, which is int.  Its callers assign the return value to int
variables, then check whether it's negative.  Unclean.

Return int instead.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-2-armbru@redhat.com>
2023-10-11 11:17:02 +02:00
Peter Xu
0e99bb8f54 migration: Allow RECOVER->PAUSED convertion for dest qemu
There's a bug on dest that if a double fault triggered on dest qemu (a
network issue during postcopy-recover), we won't set PAUSED correctly
because we assumed we always came from ACTIVE.

Fix that by always overwriting the state to PAUSE.

We could also check for these two states, but maybe it's an overkill.  We
did the same on the src QEMU to unconditionally switch to PAUSE anyway.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231004220240.167175-10-peterx@redhat.com>
2023-10-11 11:17:02 +02:00
Fabiano Rosas
4111a732e8 migration: Set migration status early in incoming side
We are sending a migration event of MIGRATION_STATUS_SETUP at
qemu_start_incoming_migration but never actually setting the state.

This creates a window between qmp_migrate_incoming and
process_incoming_migration_co where the migration status is still
MIGRATION_STATUS_NONE. Calling query-migrate during this time will
return an empty response even though the incoming migration command
has already been issued.

Commit 7cf1fe6d68 ("migration: Add migration events on target side")
has added support to the 'events' capability to the incoming part of
migration, but chose to send the SETUP event without setting the
state. I'm assuming this was a mistake.

This introduces a change in behavior, any QMP client waiting for the
SETUP event will hang, unless it has previously enabled the 'events'
capability. Having the capability enabled is sufficient to continue to
receive the event.

Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230712190742.22294-5-farosas@suse.de>
2023-10-11 11:17:02 +02:00
Peter Xu
86dec715a7 migration/qmp: Fix crash on setting tls-authz with null
QEMU will crash if anyone tries to set tls-authz (which is a type
StrOrNull) with 'null' value.  Fix it in the easy way by converting it to
qstring just like the other two tls parameters.

Cc: qemu-stable@nongnu.org # v4.0+
Fixes: d2f1d29b95 ("migration: add support for a "tls-authz" migration parameter")
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230905162335.235619-2-peterx@redhat.com>
2023-10-11 11:17:02 +02:00
Andrei Gudkov
320a6ccc76 migration/dirtyrate: use QEMU_CLOCK_HOST to report start-time
Currently query-dirty-rate uses QEMU_CLOCK_REALTIME as
the source for start-time field. This translates to
clock_gettime(CLOCK_MONOTONIC), i.e. number of seconds
since host boot. This is not very useful. The only
reasonable use case of start-time I can imagine is to
check whether previously completed measurements are
too old or not. But this makes sense only if start-time
is reported as host wall-clock time.

This patch replaces source of start-time from
QEMU_CLOCK_REALTIME to QEMU_CLOCK_HOST.

Signed-off-by: Andrei Gudkov <gudkov.andrei@huawei.com>
Reviewed-by: Hyman Huang <yong.huang@smartx.com>
Message-Id: <399861531e3b24a1ecea2ba453fb2c3d129fb03a.1693905328.git.gudkov.andrei@huawei.com>
Signed-off-by: Hyman Huang <yong.huang@smartx.com>
2023-10-10 08:04:12 +08:00
Andrei Gudkov
34a68001f1 migration/calc-dirty-rate: millisecond-granularity period
This patch allows to measure dirty page rate for
sub-second intervals of time. An optional argument is
introduced -- calc-time-unit. For example:
{"execute": "calc-dirty-rate", "arguments":
  {"calc-time": 500, "calc-time-unit": "millisecond"} }

Millisecond granularity allows to make predictions whether
migration will succeed or not. To do this, calculate dirty
rate with calc-time set to max allowed downtime (e.g. 300ms),
convert measured rate into volume of dirtied memory,
and divide by network throughput. If the value is lower
than max allowed downtime, then migration will converge.

Measurement results for single thread randomly writing to
a 1/4/24GiB memory region:

+----------------+-----------------------------------------------+
| calc-time      |                dirty rate MiB/s               |
| (milliseconds) +----------------+---------------+--------------+
|                | theoretical    | page-sampling | dirty-bitmap |
|                | (at 3M wr/sec) |               |              |
+----------------+----------------+---------------+--------------+
|                               1GiB                             |
+----------------+----------------+---------------+--------------+
|            100 |           6996 |          7100 |         3192 |
|            200 |           4606 |          4660 |         2655 |
|            300 |           3305 |          3280 |         2371 |
|            400 |           2534 |          2525 |         2154 |
|            500 |           2041 |          2044 |         1871 |
|            750 |           1365 |          1341 |         1358 |
|           1000 |           1024 |          1052 |         1025 |
|           1500 |            683 |           678 |          684 |
|           2000 |            512 |           507 |          513 |
+----------------+----------------+---------------+--------------+
|                               4GiB                             |
+----------------+----------------+---------------+--------------+
|            100 |          10232 |          8880 |         4070 |
|            200 |           8954 |          8049 |         3195 |
|            300 |           7889 |          7193 |         2881 |
|            400 |           6996 |          6530 |         2700 |
|            500 |           6245 |          5772 |         2312 |
|            750 |           4829 |          4586 |         2465 |
|           1000 |           3865 |          3780 |         2178 |
|           1500 |           2694 |          2633 |         2004 |
|           2000 |           2041 |          2031 |         1789 |
+----------------+----------------+---------------+--------------+
|                               24GiB                            |
+----------------+----------------+---------------+--------------+
|            100 |          11495 |          8640 |         5597 |
|            200 |          11226 |          8616 |         3527 |
|            300 |          10965 |          8386 |         2355 |
|            400 |          10713 |          8370 |         2179 |
|            500 |          10469 |          8196 |         2098 |
|            750 |           9890 |          7885 |         2556 |
|           1000 |           9354 |          7506 |         2084 |
|           1500 |           8397 |          6944 |         2075 |
|           2000 |           7574 |          6402 |         2062 |
+----------------+----------------+---------------+--------------+

Theoretical values are computed according to the following formula:
size * (1 - (1-(4096/size))^(time*wps)) / (time * 2^20),
where size is in bytes, time is in seconds, and wps is number of
writes per second.

Signed-off-by: Andrei Gudkov <gudkov.andrei@huawei.com>
Reviewed-by: Hyman Huang <yong.huang@smartx.com>
Message-Id: <d802e6b8053eb60fbec1a784cf86f67d9528e0a8.1693895970.git.gudkov.andrei@huawei.com>
Signed-off-by: Hyman Huang <yong.huang@smartx.com>
2023-10-10 08:03:50 +08:00
Peter Xu
579cedf430 migration: Unify and trace vmstate field_exists() checks
For both save/load we actually share the logic on deciding whether a field
should exist.  Merge the checks into a helper and use it for both save and
load.  When doing so, add documentations and reformat the code to make it
much easier to read.

The real benefit here (besides code cleanups) is we add a trace-point for
this; this is a known spot where we can easily break migration
compatibilities between binaries, and this trace point will be critical for
us to identify such issues.

For example, this will be handy when debugging things like:

https://gitlab.com/qemu-project/qemu/-/issues/932

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230906204722.514474-1-peterx@redhat.com>
2023-10-04 13:19:47 +02:00
Steve Sistare
385f510df5 migration: file URI offset
Allow an offset option to be specified as part of the file URI, in
the form "file:filename,offset=offset", where offset accepts the common
size suffixes, or the 0x prefix, but not both.  Migration data is written
to and read from the file starting at offset.  If unspecified, it defaults
to 0.

This is needed by libvirt to store its own data at the head of the file.

Suggested-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <1694182931-61390-3-git-send-email-steven.sistare@oracle.com>
2023-10-04 13:18:08 +02:00
Steve Sistare
2a9e2e595f migration: file URI
Extend the migration URI to support file:<filename>.  This can be used for
any migration scenario that does not require a reverse path.  It can be
used as an alternative to 'exec:cat > file' in minimized containers that
do not contain /bin/sh, and it is easier to use than the fd:<fdname> URI.
It can be used in HMP commands, and as a qemu command-line parameter.

For best performance, guest ram should be shared and x-ignore-shared
should be true, so guest pages are not written to the file, in which case
the guest may remain running.  If ram is not so configured, then the user
is advised to stop the guest first.  Otherwise, a busy guest may re-dirty
the same page, causing it to be appended to the file multiple times,
and the file may grow unboundedly.  That issue is being addressed in the
"fixed-ram" patch series.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Tested-by: Michael Galaxy <mgalaxy@akamai.com>
Reviewed-by: Michael Galaxy <mgalaxy@akamai.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <1694182931-61390-2-git-send-email-steven.sistare@oracle.com>
2023-10-04 13:16:58 +02:00
Li Zhijian
2ada4b63f1 migration/rdma: zore out head.repeat to make the error more clear
Previously, we got a confusion error that complains
the RDMAControlHeader.repeat:
qemu-system-x86_64: rdma: Too many requests in this message (3638950032).Bailing.

Actually, it's caused by an unexpected RDMAControlHeader.type.
After this patch, error will become:
qemu-system-x86_64: Unknown control message QEMU FILE

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230926100103.201564-2-lizhijian@fujitsu.com>
2023-10-04 10:54:41 +02:00
Tejus GK
848a050342 migration: Update error description outside migration.c
A few code paths exist in the source code,where a migration is
marked as failed via MIGRATION_STATUS_FAILED, but the failure happens
outside	of migration.c

In such	cases, an error_report() call is made, however the current
MigrationState is never	updated	with the error description, and	hence
clients	like libvirt never know	the actual reason for the failure.

This patch covers such cases outside of	migration.c and	updates	the
error description at the appropriate places.

Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Tejus GK <tejus.gk@nutanix.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231003065538.244752-3-tejus.gk@nutanix.com>
2023-10-04 10:54:40 +02:00
Tejus GK
969298f9d7 migration/vmstate: Introduce vmstate_save_state_with_err
Currently, a few code paths exist in the function vmstate_save_state_v,
which ultimately leads to a migration failure. However, an update in the
current MigrationState for the error description is never done.

vmstate.c somehow doesn't seem to allow	the use	of migrate_set_error due
to some	dependencies for unit tests. Hence, this patch introduces a new
function vmstate_save_state_with_err, which will eventually propagate
the error message to savevm.c where a migrate_set_error	call can be
eventually done.

Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Tejus GK <tejus.gk@nutanix.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231003065538.244752-2-tejus.gk@nutanix.com>
2023-10-04 10:54:40 +02:00
Stefan Hajnoczi
50d0bfd0ed Migration Pull request (20231002)
In this migration pull request:
 
 - Refactor repeated call of yank_unregister_instance (tejus)
 - More migraton-test changes
 
 Please, apply.
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Merge tag 'migration-20231002-pull-request' of https://gitlab.com/juan.quintela/qemu into staging

Migration Pull request (20231002)

In this migration pull request:

- Refactor repeated call of yank_unregister_instance (tejus)
- More migraton-test changes

Please, apply.

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# gpg: Signature made Mon 02 Oct 2023 08:20:14 EDT
# gpg:                using RSA key 1899FF8EDEBF58CCEE034B82F487EF185872D723
# gpg: Good signature from "Juan Quintela <quintela@redhat.com>" [full]
# gpg:                 aka "Juan Quintela <quintela@trasno.org>" [full]
# Primary key fingerprint: 1899 FF8E DEBF 58CC EE03  4B82 F487 EF18 5872 D723

* tag 'migration-20231002-pull-request' of https://gitlab.com/juan.quintela/qemu:
  migration/rdma: Simplify the function that saves a page
  migration: Remove unused qemu_file_credit_transfer()
  migration/rdma: Don't use imaginary transfers
  migration/rdma: Remove QEMUFile parameter when not used
  migration/RDMA: It is accounting for zero/normal pages in two places
  migration: Don't abuse qemu_file transferred for RDMA
  migration: Use qemu_file_transferred_noflush() for block migration.
  migration: Refactor repeated call of yank_unregister_instance
  migration-test: simplify shmem_opts handling
  migration-test: dirtylimit checks for x86_64 arch before
  migration-test: Add bootfile_create/delete() functions
  migration-test: bootpath is the same for all tests and for all archs
  migration-test: Create kvm_opts

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2023-10-02 14:42:44 -04:00
Juan Quintela
9c53d369e5 migration/rdma: Simplify the function that saves a page
When we sent a page through QEMUFile hooks (RDMA) there are three
posiblities:
- We are not using RDMA. return RAM_SAVE_CONTROL_DELAYED and
  control_save_page() returns false to let anything else to proceed.
- There is one error but we are using RDMA.  Then we return a negative
  value, control_save_page() needs to return true.
- Everything goes well and RDMA start the sent of the page
  asynchronously.  It returns RAM_SAVE_CONTROL_DELAYED and we need to
  return 1 for ram_save_page_legacy.

Clear?

I know, I know, the interface is as bad as it gets.  I think that now
it is a bit clearer, but this needs to be done some other way.

Reviewed-by: Leonardo Bras <leobras@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230515195709.63843-16-quintela@redhat.com>
2023-09-29 18:13:53 +02:00
Juan Quintela
9f51fe9239 migration: Remove unused qemu_file_credit_transfer()
After this change, nothing abuses QEMUFile to account for data
transferrefd during migration.

Reviewed-by: Leonardo Bras <leobras@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230515195709.63843-15-quintela@redhat.com>
2023-09-29 18:13:36 +02:00
Juan Quintela
2ebe5d4d5a migration/rdma: Don't use imaginary transfers
RDMA protocol is completely asynchronous, so in qemu_rdma_save_page()
they "invent" that a byte has been transferred.  And then they call
qemu_file_credit_transfer() and ram_transferred_add() with that byte.
Just remove that calls as nothing has been sent.

Reviewed-by: Leonardo Bras <leobras@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230515195709.63843-14-quintela@redhat.com>
2023-09-29 18:11:21 +02:00
Juan Quintela
e33780351c migration/rdma: Remove QEMUFile parameter when not used
Reviewed-by: Leonardo Bras <leobras@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230515195709.63843-13-quintela@redhat.com>
2023-09-29 18:11:21 +02:00
Juan Quintela
19df4f3226 migration/RDMA: It is accounting for zero/normal pages in two places
Remove the one in control_save_page().

Reviewed-by: Leonardo Bras <leobras@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230515195709.63843-12-quintela@redhat.com>
2023-09-29 18:11:21 +02:00
Juan Quintela
67c31c9c1a migration: Don't abuse qemu_file transferred for RDMA
Just create a variable for it, the same way that multifd does.  This
way it is safe to use for other thread, etc, etc.

Reviewed-by: Leonardo Bras <leobras@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230515195709.63843-11-quintela@redhat.com>
2023-09-29 18:11:21 +02:00
Juan Quintela
f16ecfa9f9 migration: Use qemu_file_transferred_noflush() for block migration.
We only care about the amount of bytes transferred.  Flushing is done
by the system somewhere else.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230530183941.7223-4-quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-09-29 17:05:23 +02:00
Tejus GK
f4e1b61336 migration: Refactor repeated call of yank_unregister_instance
In the function qmp_migrate(), yank_unregister_instance() gets called
twice which isn't required. Hence, refactoring it so that it gets called
during the local_error cleanup.

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Tejus GK <tejus.gk@nutanix.com>
Message-ID: <20230621130940.178659-3-tejus.gk@nutanix.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-09-29 17:05:23 +02:00
Markus Armbruster
7f3de3f02f migration: Clean up local variable shadowing
Local variables shadowing other local variables or parameters make the
code needlessly hard to understand.  Tracked down with -Wshadow=local.
Clean up: delete inner declarations when they are actually redundant,
else rename variables.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Message-ID: <20230921121312.1301864-3-armbru@redhat.com>
2023-09-29 08:13:57 +02:00
Markus Armbruster
bbde656263 migration/rdma: Fix save_page method to fail on polling error
qemu_rdma_save_page() reports polling error with error_report(), then
succeeds anyway.  This is because the variable holding the polling
status *shadows* the variable the function returns.  The latter
remains zero.

Broken since day one, and duplicated more recently.

Fixes: 2da776db48 (rdma: core logic)
Fixes: b390afd8c5 (migration/rdma: Fix out of order wrid)
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Message-ID: <20230921121312.1301864-2-armbru@redhat.com>
2023-09-29 08:13:57 +02:00
Fabiano Rosas
36e9aab3c5 migration: Move return path cleanup to main migration thread
Now that the return path thread is allowed to finish during a paused
migration, we can move the cleanup of the QEMUFiles to the main
migration thread.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230918172822.19052-9-farosas@suse.de>
2023-09-27 13:58:02 -04:00
Fabiano Rosas
ef796ee93b migration: Replace the return path retry logic
Replace the return path retry logic with finishing and restarting the
thread. This fixes a race when resuming the migration that leads to a
segfault.

Currently when doing postcopy we consider that an IO error on the
return path file could be due to a network intermittency. We then keep
the thread alive but have it do cleanup of the 'from_dst_file' and
wait on the 'postcopy_pause_rp' semaphore. When the user issues a
migrate resume, a new return path is opened and the thread is allowed
to continue.

There's a race condition in the above mechanism. It is possible for
the new return path file to be setup *before* the cleanup code in the
return path thread has had a chance to run, leading to the *new* file
being closed and the pointer set to NULL. When the thread is released
after the resume, it tries to dereference 'from_dst_file' and crashes:

Thread 7 "return path" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffd1dbf700 (LWP 9611)]
0x00005555560e4893 in qemu_file_get_error_obj (f=0x0, errp=0x0) at ../migration/qemu-file.c:154
154         return f->last_error;

(gdb) bt
 #0  0x00005555560e4893 in qemu_file_get_error_obj (f=0x0, errp=0x0) at ../migration/qemu-file.c:154
 #1  0x00005555560e4983 in qemu_file_get_error (f=0x0) at ../migration/qemu-file.c:206
 #2  0x0000555555b9a1df in source_return_path_thread (opaque=0x555556e06000) at ../migration/migration.c:1876
 #3  0x000055555602e14f in qemu_thread_start (args=0x55555782e780) at ../util/qemu-thread-posix.c:541
 #4  0x00007ffff38d76ea in start_thread (arg=0x7fffd1dbf700) at pthread_create.c:477
 #5  0x00007ffff35efa6f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Here's the race (important bit is open_return_path happening before
migration_release_dst_files):

migration                 | qmp                         | return path
--------------------------+-----------------------------+---------------------------------
			    qmp_migrate_pause()
			     shutdown(ms->to_dst_file)
			      f->last_error = -EIO
migrate_detect_error()
 postcopy_pause()
  set_state(PAUSED)
  wait(postcopy_pause_sem)
			    qmp_migrate(resume)
			    migrate_fd_connect()
			     resume = state == PAUSED
			     open_return_path <-- TOO SOON!
			     set_state(RECOVER)
			     post(postcopy_pause_sem)
							(incoming closes to_src_file)
							res = qemu_file_get_error(rp)
							migration_release_dst_files()
							ms->rp_state.from_dst_file = NULL
  post(postcopy_pause_rp_sem)
							postcopy_pause_return_path_thread()
							  wait(postcopy_pause_rp_sem)
							rp = ms->rp_state.from_dst_file
							goto retry
							qemu_file_get_error(rp)
							SIGSEGV
-------------------------------------------------------------------------------------------

We can keep the retry logic without having the thread alive and
waiting. The only piece of data used by it is the 'from_dst_file' and
it is only allowed to proceed after a migrate resume is issued and the
semaphore released at migrate_fd_connect().

Move the retry logic to outside the thread by waiting for the thread
to finish before pausing the migration.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230918172822.19052-8-farosas@suse.de>
2023-09-27 13:58:02 -04:00
Fabiano Rosas
d50f5dc075 migration: Consolidate return path closing code
We'll start calling the await_return_path_close_on_source() function
from other parts of the code, so move all of the related checks and
tracepoints into it.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230918172822.19052-7-farosas@suse.de>
2023-09-27 13:58:02 -04:00
Fabiano Rosas
b3b101157d migration: Remove redundant cleanup of postcopy_qemufile_src
This file is owned by the return path thread which is already doing
cleanup.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230918172822.19052-6-farosas@suse.de>
2023-09-27 13:58:02 -04:00
Fabiano Rosas
7478fb0df9 migration: Fix possible race when shutting down to_dst_file
It's not safe to call qemu_file_shutdown() on the to_dst_file without
first checking for the file's presence under the lock. The cleanup of
this file happens at postcopy_pause() and migrate_fd_cleanup() which
are not necessarily running in the same thread as migrate_fd_cancel().

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230918172822.19052-5-farosas@suse.de>
2023-09-27 13:58:02 -04:00
Fabiano Rosas
639decf529 migration: Fix possible races when shutting down the return path
We cannot call qemu_file_shutdown() on the return path file without
taking the file lock. The return path thread could be running it's
cleanup code and have just cleared the from_dst_file pointer.

Checking ms->to_dst_file for errors could also race with
migrate_fd_cleanup() which clears the to_dst_file pointer.

Protect both accesses by taking the file lock.

This was caught by inspection, it should be rare, but the next patches
will start calling this code from other places, so let's do the
correct thing.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230918172822.19052-4-farosas@suse.de>
2023-09-27 13:58:02 -04:00
Fabiano Rosas
28a8347281 migration: Fix possible race when setting rp_state.error
We don't need to set the rp_state.error right after a shutdown because
qemu_file_shutdown() always sets the QEMUFile error, so the return
path thread would have seen it and set the rp error itself.

Setting the error outside of the thread is also racy because the
thread could clear it after we set it.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230918172822.19052-3-farosas@suse.de>
2023-09-27 13:58:02 -04:00
Peter Xu
cf02f29e1e migration: Fix race that dest preempt thread close too early
We hit intermit CI issue on failing at migration-test over the unit test
preempt/plain:

qemu-system-x86_64: Unable to read from socket: Connection reset by peer
Memory content inconsistency at 5b43000 first_byte = bd last_byte = bc current = 4f hit_edge = 1
**
ERROR:../tests/qtest/migration-test.c:300:check_guests_ram: assertion failed: (bad == 0)
(test program exited with status code -6)

Fabiano debugged into it and found that the preempt thread can quit even
without receiving all the pages, which can cause guest not receiving all
the pages and corrupt the guest memory.

To make sure preempt thread finished receiving all the pages, we can rely
on the page_requested_count being zero because preempt channel will only
receive requested page faults. Note, not all the faulted pages are required
to be sent via the preempt channel/thread; imagine the case when a
requested page is just queued into the background main channel for
migration, the src qemu will just still send it via the background channel.

Here instead of spinning over reading the count, we add a condvar so the
main thread can wait on it if that unusual case happened, without burning
the cpu for no good reason, even if the duration is short; so even if we
spin in this rare case is probably fine.  It's just better to not do so.

The condvar is only used when that special case is triggered.  Some memory
ordering trick is needed to guarantee it from happening (against the
preempt thread status field), so the main thread will always get a kick
when that triggers correctly.

Closes: https://gitlab.com/qemu-project/qemu/-/issues/1886
Debugged-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230918172822.19052-2-farosas@suse.de>
2023-09-27 13:58:02 -04:00
Avihai Horon
08fc4cb517 migration: Add .save_prepare() handler to struct SaveVMHandlers
Add a new .save_prepare() handler to struct SaveVMHandlers. This handler
is called early, even before migration starts, and can be used by
devices to perform early checks.

Refactor migrate_init() to be able to return errors and call
.save_prepare() from there.

Suggested-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2023-09-11 08:34:06 +02:00
Avihai Horon
f543aa222d migration: Move more initializations to migrate_init()
Initialization of mig_stats, compression_counters and VFIO bytes
transferred is hard-coded in migration code path and snapshot code path.

Make the code cleaner by initializing them in migrate_init().

Suggested-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2023-09-11 08:34:06 +02:00
Avihai Horon
38c482b477 migration: Add migration prefix to functions in target.c
The functions in target.c are not static, yet they don't have a proper
migration prefix. Add such prefix.

Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2023-09-11 08:34:06 +02:00
Stefan Hajnoczi
06e0f098d6 io: follow coroutine AioContext in qio_channel_yield()
The ongoing QEMU multi-queue block layer effort makes it possible for multiple
threads to process I/O in parallel. The nbd block driver is not compatible with
the multi-queue block layer yet because QIOChannel cannot be used easily from
coroutines running in multiple threads. This series changes the QIOChannel API
to make that possible.

In the current API, calling qio_channel_attach_aio_context() sets the
AioContext where qio_channel_yield() installs an fd handler prior to yielding:

  qio_channel_attach_aio_context(ioc, my_ctx);
  ...
  qio_channel_yield(ioc); // my_ctx is used here
  ...
  qio_channel_detach_aio_context(ioc);

This API design has limitations: reading and writing must be done in the same
AioContext and moving between AioContexts involves a cumbersome sequence of API
calls that is not suitable for doing on a per-request basis.

There is no fundamental reason why a QIOChannel needs to run within the
same AioContext every time qio_channel_yield() is called. QIOChannel
only uses the AioContext while inside qio_channel_yield(). The rest of
the time, QIOChannel is independent of any AioContext.

In the new API, qio_channel_yield() queries the AioContext from the current
coroutine using qemu_coroutine_get_aio_context(). There is no need to
explicitly attach/detach AioContexts anymore and
qio_channel_attach_aio_context() and qio_channel_detach_aio_context() are gone.
One coroutine can read from the QIOChannel while another coroutine writes from
a different AioContext.

This API change allows the nbd block driver to use QIOChannel from any thread.
It's important to keep in mind that the block driver already synchronizes
QIOChannel access and ensures that two coroutines never read simultaneously or
write simultaneously.

This patch updates all users of qio_channel_attach_aio_context() to the
new API. Most conversions are simple, but vhost-user-server requires a
new qemu_coroutine_yield() call to quiesce the vu_client_trip()
coroutine when not attached to any AioContext.

While the API is has become simpler, there is one wart: QIOChannel has a
special case for the iohandler AioContext (used for handlers that must not run
in nested event loops). I didn't find an elegant way preserve that behavior, so
I added a new API called qio_channel_set_follow_coroutine_ctx(ioc, true|false)
for opting in to the new AioContext model. By default QIOChannel uses the
iohandler AioHandler. Code that formerly called
qio_channel_attach_aio_context() now calls
qio_channel_set_follow_coroutine_ctx(ioc, true) once after the QIOChannel is
created.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Acked-by: Daniel P. Berrangé <berrange@redhat.com>
Message-ID: <20230830224802.493686-5-stefanha@redhat.com>
[eblake: also fix migration/rdma.c]
Signed-off-by: Eric Blake <eblake@redhat.com>
2023-09-07 20:32:11 -05:00
Stefan Hajnoczi
156618d9ea Pull request
v3:
 - Drop UFS emulation due to CI failures
 - Add "aio-posix: zero out io_uring sqe user_data"
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Merge tag 'block-pull-request' of https://gitlab.com/stefanha/qemu into staging

Pull request

v3:
- Drop UFS emulation due to CI failures
- Add "aio-posix: zero out io_uring sqe user_data"

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# gpg: Signature made Wed 30 Aug 2023 07:48:17 EDT
# gpg:                using RSA key 8695A8BFD3F97CDAAC35775A9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>" [ultimate]
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>" [ultimate]
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* tag 'block-pull-request' of https://gitlab.com/stefanha/qemu:
  aio-posix: zero out io_uring sqe user_data
  tests/qemu-iotests/197: add testcase for CoR with subclusters
  block/io: align requests to subcluster_size
  block: add subcluster_size field to BlockDriverInfo
  block-migration: Ensure we don't crash during migration cleanup

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2023-08-30 09:20:27 -04:00
Fabiano Rosas
f187609f27 block-migration: Ensure we don't crash during migration cleanup
We can fail the blk_insert_bs() at init_blk_migration(), leaving the
BlkMigDevState without a dirty_bitmap and BlockDriverState. Account
for the possibly missing elements when doing cleanup.

Fix the following crashes:

Thread 1 "qemu-system-x86" received signal SIGSEGV, Segmentation fault.
0x0000555555ec83ef in bdrv_release_dirty_bitmap (bitmap=0x0) at ../block/dirty-bitmap.c:359
359         BlockDriverState *bs = bitmap->bs;
 #0  0x0000555555ec83ef in bdrv_release_dirty_bitmap (bitmap=0x0) at ../block/dirty-bitmap.c:359
 #1  0x0000555555bba331 in unset_dirty_tracking () at ../migration/block.c:371
 #2  0x0000555555bbad98 in block_migration_cleanup_bmds () at ../migration/block.c:681

Thread 1 "qemu-system-x86" received signal SIGSEGV, Segmentation fault.
0x0000555555e971ff in bdrv_op_unblock (bs=0x0, op=BLOCK_OP_TYPE_BACKUP_SOURCE, reason=0x0) at ../block.c:7073
7073        QLIST_FOREACH_SAFE(blocker, &bs->op_blockers[op], list, next) {
 #0  0x0000555555e971ff in bdrv_op_unblock (bs=0x0, op=BLOCK_OP_TYPE_BACKUP_SOURCE, reason=0x0) at ../block.c:7073
 #1  0x0000555555e9734a in bdrv_op_unblock_all (bs=0x0, reason=0x0) at ../block.c:7095
 #2  0x0000555555bbae13 in block_migration_cleanup_bmds () at ../migration/block.c:690

Signed-off-by: Fabiano Rosas <farosas@suse.de>
Message-id: 20230731203338.27581-1-farosas@suse.de
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2023-08-30 07:39:10 -04:00
Andrei Gudkov
3eb82637fb migration/dirtyrate: Fix precision losses and g_usleep overshoot
Signed-off-by: Andrei Gudkov <gudkov.andrei@huawei.com>
Reviewed-by: Hyman Huang <yong.huang@smartx.com>
Message-Id: <8ddb0d40d143f77aab8f602bd494e01e5fa01614.1691161009.git.gudkov.andrei@huawei.com>
Signed-off-by: Hyman Huang <yong.huang@smartx.com>
2023-08-29 10:19:03 +08:00
Juan Quintela
697c4c86ab migration/rdma: Split qemu_fopen_rdma() into input/output functions
This is how everything else in QEMUFile is structured.
As a bonus they are three less lines of code.

Reviewed-by: Peter Xu <peterx@redhat.com>
Message-ID: <20230530183941.7223-17-quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-07-26 10:55:56 +02:00
Juan Quintela
ac6f48e15d qemu-file: Make qemu_file_get_error_obj() static
It was not used outside of qemu_file.c anyways.

Reviewed-by: Peter Xu <peterx@redhat.com>
Message-ID: <20230530183941.7223-21-quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-07-26 10:55:56 +02:00
Juan Quintela
8c5ee0bfb8 qemu-file: Simplify qemu_file_shutdown()
Reviewed-by: Peter Xu <peterx@redhat.com>
Message-ID: <20230530183941.7223-20-quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-07-26 10:55:56 +02:00
Juan Quintela
9ccf83f486 qemu_file: Make qemu_file_is_writable() static
It is not used outside of qemu_file, and it shouldn't.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230530183941.7223-19-quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-07-26 10:55:56 +02:00
Juan Quintela
cf786549ce migration: Change qemu_file_transferred to noflush
We do a qemu_fclose() just after that, that also does a qemu_fflush(),
so remove one qemu_fflush().

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20230530183941.7223-3-quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-07-26 10:55:56 +02:00
Juan Quintela
fc95c63b60 qemu-file: Rename qemu_file_transferred_ fast -> noflush
Fast don't say much.  Noflush indicates more clearly that it is like
qemu_file_transferred but without the flush.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20230530183941.7223-2-quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-07-26 10:55:56 +02:00
Wei Wang
82137e6c8c migration: enforce multifd and postcopy preempt to be set before incoming
qemu_start_incoming_migration needs to check the number of multifd
channels or postcopy ram channels to configure the backlog parameter (i.e.
the maximum length to which the queue of pending connections for sockfd
may grow) of listen(). So enforce the usage of postcopy-preempt and
multifd as below:
- need to use "-incoming defer" on the destination; and
- set_capability and set_parameter need to be done before migrate_incoming

Otherwise, disable the use of the features and report error messages to
remind users to adjust the commands.

Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230606101910.20456-2-wei.w.wang@intel.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Acked-by: Juan Quintela <quintela@redhat.com>
2023-07-26 10:55:56 +02:00
Tejus GK
908927db28 migration: Update error description whenever migration fails
There are places in migration.c where the migration is marked failed with
MIGRATION_STATUS_FAILED, but the failure reason is never updated. Hence
libvirt doesn't know why the migration failed when it queries for it.

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Tejus GK <tejus.gk@nutanix.com>
Message-ID: <20230621130940.178659-2-tejus.gk@nutanix.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-07-26 10:55:56 +02:00
Hyman Huang(黄勇)
15699cf542 migration: Extend query-migrate to provide dirty page limit info
Extend query-migrate to provide throttle time and estimated
ring full time with dirty-limit capability enabled, through which
we can observe if dirty limit take effect during live migration.

Signed-off-by: Hyman Huang(黄勇) <yong.huang@smartx.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-ID: <168733225273.5845.15871826788879741674-8@git.sr.ht>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-07-26 10:55:56 +02:00
Hyman Huang(黄勇)
acac51ba24 migration: Implement dirty-limit convergence algo
Implement dirty-limit convergence algo for live migration,
which is kind of like auto-converge algo but using dirty-limit
instead of cpu throttle to make migration convergent.

Enable dirty page limit if dirty_rate_high_cnt greater than 2
when dirty-limit capability enabled, Disable dirty-limit if
migration be canceled.

Note that "set_vcpu_dirty_limit", "cancel_vcpu_dirty_limit"
commands are not allowed during dirty-limit live migration.

Signed-off-by: Hyman Huang(黄勇) <yong.huang@smartx.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <168733225273.5845.15871826788879741674-7@git.sr.ht>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-07-26 10:55:56 +02:00
Hyman Huang(黄勇)
310ad5625e migration: Put the detection logic before auto-converge checking
This commit is prepared for the implementation of dirty-limit
convergence algo.

The detection logic of throttling condition can apply to both
auto-converge and dirty-limit algo, putting it's position
before the checking logic for auto-converge feature.

Signed-off-by: Hyman Huang(黄勇) <yong.huang@smartx.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-ID: <168733225273.5845.15871826788879741674-6@git.sr.ht>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-07-26 10:55:56 +02:00
Hyman Huang(黄勇)
bb9993c672 migration: Refactor auto-converge capability logic
Check if block migration is running before throttling
guest down in auto-converge way.

Note that this modification is kind of like code clean,
because block migration does not depend on auto-converge
capability, so the order of checks can be adjusted.

Signed-off-by: Hyman Huang(黄勇) <yong.huang@smartx.com>
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <168618975839.6361.17407633874747688653-5@git.sr.ht>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-07-26 10:55:56 +02:00
Hyman Huang(黄勇)
dc62395557 migration: Introduce dirty-limit capability
Introduce migration dirty-limit capability, which can
be turned on before live migration and limit dirty
page rate durty live migration.

Introduce migrate_dirty_limit function to help check
if dirty-limit capability enabled during live migration.

Meanwhile, refactor vcpu_dirty_rate_stat_collect
so that period can be configured instead of hardcoded.

dirty-limit capability is kind of like auto-converge
but using dirty limit instead of traditional cpu-throttle
to throttle guest down. To enable this feature, turn on
the dirty-limit capability before live migration using
migrate-set-capabilities, and set the parameters
"x-vcpu-dirty-limit-period", "vcpu-dirty-limit" suitably
to speed up convergence.

Signed-off-by: Hyman Huang(黄勇) <yong.huang@smartx.com>
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <168618975839.6361.17407633874747688653-4@git.sr.ht>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-07-26 10:55:56 +02:00
Hyman Huang(黄勇)
09f9ec9913 qapi/migration: Introduce vcpu-dirty-limit parameters
Introduce "vcpu-dirty-limit" migration parameter used
to limit dirty page rate during live migration.

"vcpu-dirty-limit" and "x-vcpu-dirty-limit-period" are
two dirty-limit-related migration parameters, which can
be set before and during live migration by qmp
migrate-set-parameters.

This two parameters are used to help implement the dirty
page rate limit algo of migration.

Signed-off-by: Hyman Huang(黄勇) <yong.huang@smartx.com>
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <168618975839.6361.17407633874747688653-3@git.sr.ht>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-07-26 10:55:56 +02:00
Hyman Huang(黄勇)
4d80785719 qapi/migration: Introduce x-vcpu-dirty-limit-period parameter
Introduce "x-vcpu-dirty-limit-period" migration experimental
parameter, which is in the range of 1 to 1000ms and used to
make dirtyrate calculation period configurable.

Currently with the "x-vcpu-dirty-limit-period" varies, the
total time of live migration changes, test results show the
optimal value of "x-vcpu-dirty-limit-period" ranges from
500ms to 1000 ms. "x-vcpu-dirty-limit-period" should be made
stable once it proves best value can not be determined with
developer's experiments.

Signed-off-by: Hyman Huang(黄勇) <yong.huang@smartx.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <168618975839.6361.17407633874747688653-2@git.sr.ht>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-07-26 10:55:56 +02:00
Fabiano Rosas
01ec0f3a92 migration/multifd: Protect accesses to migration_threads
This doubly linked list is common for all the multifd and migration
threads so we need to avoid concurrent access.

Add a mutex to protect the data from concurrent access. This fixes a
crash when removing two MigrationThread objects from the list at the
same time during cleanup of multifd threads.

Fixes: 671326201d ("migration: Introduce interface query-migrationthreads")
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230607161306.31425-3-farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-07-26 10:55:56 +02:00
Fabiano Rosas
788fa68041 migration/multifd: Rename threadinfo.c functions
We're about to add more functions to this file so make it use the same
coding style as the rest of the code.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Message-Id: <20230607161306.31425-2-farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2023-07-26 10:55:56 +02:00
Michael Tokarev
d8b71d96b3 migration: spelling fixes
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
2023-07-25 17:13:20 +03:00
David Hildenbrand
f161c88a03 migration/ram: Expose ramblock_is_ignored() as migrate_ram_is_ignored()
virtio-mem wants to know whether it should not mess with the RAMBlock
content (e.g., discard RAM, preallocate memory) on incoming migration.

So let's expose that function as migrate_ram_is_ignored() in
migration/misc.h

Message-ID: <20230706075612.67404-4-david@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Tested-by: Mario Casquero <mcasquer@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
2023-07-12 09:25:37 +02:00
Laszlo Ersek
aaf26bd382 migration: unexport migrate_fd_error()
The only migrate_fd_error() call sites are in "migration/migration.c",
which is also where we define migrate_fd_error(). Make the function
static, and remove its declaration from "migration/migration.h".

Cc: Juan Quintela <quintela@redhat.com> (maintainer:Migration)
Cc: Leonardo Bras <leobras@redhat.com> (reviewer:Migration)
Cc: Peter Xu <peterx@redhat.com> (reviewer:Migration)
Cc: qemu-trivial@nongnu.org
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2018404
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2023-07-08 07:24:38 +03:00
Laszlo Ersek
8c69ae9eff migration: factor out "resume_requested" in qmp_migrate()
It cuts back on those awkward, duplicated !(has_resume && resume)
expressions.

Cc: Juan Quintela <quintela@redhat.com> (maintainer:Migration)
Cc: Leonardo Bras <leobras@redhat.com> (reviewer:Migration)
Cc: Peter Xu <peterx@redhat.com> (reviewer:Migration)
Cc: qemu-trivial@nongnu.org
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2018404
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2023-07-08 07:24:38 +03:00
Avihai Horon
808642a2f6 vfio/migration: Reset bytes_transferred properly
Currently, VFIO bytes_transferred is not reset properly:
1. bytes_transferred is not reset after a VM snapshot (so a migration
   following a snapshot will report incorrect value).
2. bytes_transferred is a single counter for all VFIO devices, however
   upon migration failure it is reset multiple times, by each VFIO
   device.

Fix it by introducing a new function vfio_reset_bytes_transferred() and
calling it during migration and snapshot start.

Remove existing bytes_transferred reset in VFIO migration state
notifier, which is not needed anymore.

Fixes: 3710586caa ("qapi: Add VFIO devices migration stats in Migration stats")
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2023-06-30 06:02:51 +02:00
Avihai Horon
538ef4fe2f migration: Enable switchover ack capability
Now that switchover ack logic has been implemented, enable the
capability.

Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Tested-by: YangHang Liu <yanghliu@redhat.com>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2023-06-30 06:02:51 +02:00
Avihai Horon
1b4adb10f8 migration: Implement switchover ack logic
Implement switchover ack logic. This prevents the source from stopping
the VM and completing the migration until an ACK is received from the
destination that it's OK to do so.

To achieve this, a new SaveVMHandlers handler switchover_ack_needed()
and a new return path message MIG_RP_MSG_SWITCHOVER_ACK are added.

The switchover_ack_needed() handler is called during migration setup in
the destination to check if switchover ack is used by the migrated
device.

When switchover is approved by all migrated devices in the destination
that support this capability, the MIG_RP_MSG_SWITCHOVER_ACK return path
message is sent to the source to notify it that it's OK to do
switchover.

Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Tested-by: YangHang Liu <yanghliu@redhat.com>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2023-06-30 06:02:51 +02:00
Avihai Horon
6574232fff migration: Add switchover ack capability
Migration downtime estimation is calculated based on bandwidth and
remaining migration data. This assumes that loading of migration data in
the destination takes a negligible amount of time and that downtime
depends only on network speed.

While this may be true for RAM, it's not necessarily true for other
migrated devices. For example, loading the data of a VFIO device in the
destination might require from the device to allocate resources, prepare
internal data structures and so on. These operations can take a
significant amount of time which can increase migration downtime.

This patch adds a new capability "switchover ack" that prevents the
source from stopping the VM and completing the migration until an ACK
is received from the destination that it's OK to do so.

This can be used by migrated devices in various ways to reduce downtime.
For example, a device can send initial precopy metadata to pre-allocate
resources in the destination and use this capability to make sure that
the pre-allocation is completed before the source VM is stopped, so it
will have full effect.

This new capability relies on the return path capability to communicate
from the destination back to the source.

The actual implementation of the capability will be added in the
following patches.

Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Tested-by: YangHang Liu <yanghliu@redhat.com>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2023-06-30 06:02:51 +02:00
Philippe Mathieu-Daudé
de6cd7599b meson: Replace softmmu_ss -> system_ss
We use the user_ss[] array to hold the user emulation sources,
and the softmmu_ss[] array to hold the system emulation ones.
Hold the latter in the 'system_ss[]' array for parity with user
emulation.

Mechanical change doing:

  $ sed -i -e s/softmmu_ss/system_ss/g $(git grep -l softmmu_ss)

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230613133347.82210-10-philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-06-20 10:01:30 +02:00
Philippe Mathieu-Daudé
c7b64948f8 meson: Replace CONFIG_SOFTMMU -> CONFIG_SYSTEM_ONLY
Since we *might* have user emulation with softmmu,
use the clearer 'CONFIG_SYSTEM_ONLY' key to check
for system emulation.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230613133347.82210-9-philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-06-20 10:01:30 +02:00
Steve Sistare
b0182e537e exec/memory: Introduce RAM_NAMED_FILE flag
migrate_ignore_shared() is an optimization that avoids copying memory
that is visible and can be mapped on the target.  However, a
memory-backend-ram or a memory-backend-memfd block with the RAM_SHARED
flag set is not migrated when migrate_ignore_shared() is true.  This is
wrong, because the block has no named backing store, and its contents will
be lost.  To fix, ignore shared memory iff it is a named file.  Define a
new flag RAM_NAMED_FILE to distinguish this case.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Message-Id: <1686151116-253260-1-git-send-email-steven.sistare@oracle.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
2023-06-13 11:28:58 +02:00
Philippe Mathieu-Daudé
7d5b0d6864 bulk: Remove pointless QOM casts
Mechanical change running Coccinelle spatch with content
generated from the qom-cast-macro-clean-cocci-gen.py added
in the previous commit.

Suggested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230601093452.38972-3-philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2023-06-05 20:48:34 +02:00