qatomic_mb_read and qatomic_mb_set were the very first atomic primitives
introduced for QEMU; their semantics are unclear and they provide a false
sense of safety.
The last use of qatomic_mb_read() has been removed, so delete it.
qatomic_mb_set() instead can survive as an optimized
qatomic_set()+smp_mb(), similar to Linux's smp_store_mb(), but
rename it to qatomic_set_mb() to match the order of the two
operations.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
bdrv_pad_request() was the main user of qemu_iovec_init_extended().
HEAD^ has removed that use, so we can remove qemu_iovec_init_extended()
now.
The only remaining user is qemu_iovec_init_slice(), which can easily
inline the small part it really needs.
Note that qemu_iovec_init_extended() offered a memcpy() optimization to
initialize the new I/O vector. qemu_iovec_concat_iov(), which is used
to replace its functionality, does not, but calls qemu_iovec_add() for
every single element. If we decide this optimization was important, we
will need to re-implement it in qemu_iovec_concat_iov(), which might
also benefit its pre-existing users.
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230411173418.19549-4-hreitz@redhat.com>
We want to inline qemu_iovec_init_extended() in block/io.c for padding
requests, and having access to qiov_slice() is useful for this. As a
public function, it is renamed to qemu_iovec_slice().
(We will need to count the number of I/O vector elements of a slice
there, and then later process this slice. Without qiov_slice(), we
would need to call qemu_iovec_subvec_niov(), and all further
IOV-processing functions may need to skip prefixing elements to
accomodate for a qiov_offset. Because qemu_iovec_subvec_niov()
internally calls qiov_slice(), we can just have the block/io.c code call
qiov_slice() itself, thus get the number of elements, and also create an
iovec array with the superfluous prefixing elements stripped, so the
following processing functions no longer need to skip them.)
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230411173418.19549-2-hreitz@redhat.com>
We have several limitations and bugs worth fixing; they are
inter-related enough that it is not worth splitting this patch into
smaller pieces:
* ".5k" should work to specify 512, just as "0.5k" does
* "1.9999k" and "1." + "9"*50 + "k" should both produce the same
result of 2048 after rounding
* "1." + "0"*350 + "1B" should not be treated the same as "1.0B";
underflow in the fraction should not be lost
* "7.99e99" and "7.99e999" look similar, but our code was doing a
read-out-of-bounds on the latter because it was not expecting ERANGE
due to overflow. While we document that scientific notation is not
supported, and the previous patch actually fixed
qemu_strtod_finite() to no longer return ERANGE overflows, it is
easier to pre-filter than to try and determine after the fact if
strtod() consumed more than we wanted. Note that this is a
low-level semantic change (when endptr is not NULL, we can now
successfully parse with a scale of 'E' and then report trailing
junk, instead of failing outright with EINVAL); but an earlier
commit already argued that this is not a high-level semantic change
since the only caller passing in a non-NULL endptr also checks that
the tail is whitespace-only.
Fixes: https://gitlab.com/qemu-project/qemu/-/issues/1629
Fixes: cf923b78 ("utils: Improve qemu_strtosz() to have 64 bits of precision", 6.0.0)
Fixes: 7625a1ed ("utils: Use fixed-point arithmetic in qemu_strtosz", 6.0.0)
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-20-eblake@redhat.com>
[eblake: tweak function comment for accuracy]
Previous patches changed all integral qemu_strto*() error paths to
guarantee that *value is never left uninitialized. Do likewise for
qemu_strtod. Also, tighten qemu_strtod_finite() to never return a
non-finite value (prior to this patch, we were rejecting "inf" with
-EINVAL and unspecified result 0.0, but failing "9e999" with -ERANGE
and HUGE_VAL - which is infinite on IEEE machines - despite our
function claiming to recognize only finite values).
Auditing callers, we have no external callers of qemu_strtod, and
among the callers of qemu_strtod_finite:
- qapi/qobject-input-visitor.c:qobject_input_type_number_keyval() and
qapi/string-input-visitor.c:parse_type_number() which reject all
errors (does not matter what we store)
- utils/cutils.c:do_strtosz() incorrectly assumes that *endptr points
to '.' on all failures (that is, it is not distinguishing between
EINVAL and ERANGE; and therefore still does the WRONG THING for
"9.9e999". The change here does not entirely fix that (a later
patch will tackle this more systematically), but at least it fixes
the read-out-of-bounds first diagnosed in
https://gitlab.com/qemu-project/qemu/-/issues/1629
- our testsuite, which we can update to match what we document
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
CC: qemu-stable@nongnu.org
Message-Id: <20230522190441.64278-19-eblake@redhat.com>
Rather than open-coding two different ways to check for an unwanted
negative sign, reuse the same code in both functions. That way, if we
decide down the road to accept "-0" instead of rejecting it, we have
fewer places to change. Also, it means we now get ERANGE instead of
EINVAL for negative values in qemu_strtosz, which is reasonable for
what it represents. This in turn changes the expected output of a
couple of iotests.
The change is not quite complete: negative fractional scaled values
can trip us up. This will be fixed in a later patch addressing other
issues with fractional scaled values.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-18-eblake@redhat.com>
Our goal in writing qemu_strtoi() and friends is to have an interface
harder to abuse than libc's strtol(). Leaving the return value
uninitialized on some but not all error paths does not lend itself
well to this goal; and our documentation wasn't helpful on what to
expect.
Note that the previous patch changed all qemu_strtosz() EINVAL error
paths to slam value to 0 rather than stay uninitialized, even when the
EINVAL eror occurs because of trailing junk. But for the remaining
integral qemu_strto*, it's easier to return the parsed value than to
force things back to zero, in part because of how check_strtox_error
works; in part because people expect that from libc strto* (while
there is no libc strtosz to compare to), and in part because doing so
creates less churn in the testsuite.
Here, the list of affected callers is much longer ('git grep
"qemu_strto[ui]" "*.c" "**/*.c" | grep -v tests/ |wc -l' outputs 107,
although a few of those are the implementation in in cutils.c), so
touching as little as possible is the wisest course of action.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-17-eblake@redhat.com>
Making callers determine whether or not *value was populated on error
is not nice for usability. Pre-patch, we have unit tests that check
that *result is left unchanged on most EINVAL errors and set to 0 on
many ERANGE errors. This is subtly different from libc strtoumax()
behavior which returns UINT64_MAX on ERANGE errors, as well as
different from our parse_uint() which slams to 0 on EINVAL on the
grounds that we want our functions to be harder to mis-use than
strtoumax().
Let's audit callers:
- hw/core/numa.c:parse_numa() fixed in the previous patch to check for
errors
- migration/migration-hmp-cmds.c:hmp_migrate_set_parameter(),
monitor/hmp.c:monitor_parse_arguments(),
qapi/opts-visitor.c:opts_type_size(),
qapi/qobject-input-visitor.c:qobject_input_type_size_keyval(),
qemu-img.c:cvtnum_full(), qemu-io-cmds.c:cvtnum(),
target/i386/cpu.c:x86_cpu_parse_featurestr(), and
util/qemu-option.c:parse_option_size() appear to reject all failures
(although some with distinct messages for ERANGE as opposed to
EINVAL), so it doesn't matter what is in the value parameter on
error.
- All remaining callers are in the testsuite, where we can tweak our
expectations to match our new desired behavior.
Advancing to the end of the string parsed on overflow (ERANGE), while
still returning 0, makes sense (UINT64_MAX as a size is unlikely to be
useful); likewise, our size parsing code is complex enough that it's
easier to always return 0 when endptr is NULL but trailing garbage was
found, rather than trying to return the value of the prefix actually
parsed (no current caller cared about the value of the prefix).
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-16-eblake@redhat.com>
All the other qemu_strto* and parse_uint allow a NULL str. Having
qemu_strtosz not crash on qemu_strtosz(NULL, NULL, &value) is an easy
fix that adds some consistency between our string parsers.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-13-eblake@redhat.com>
All the qemu_strto*() functions permit a NULL endptr, just like their
libc counterparts, leaving parse_uint() as the oddball that caused
SEGFAULT on NULL and required the user to call parse_uint_full()
instead. Relax things for consistency, even though the testsuite is
the only impacted caller. Add one more unit test to ensure even
parse_uint_full(NULL, 0, &value) works. This also fixes our code to
uniformly favor EINVAL over ERANGE when both apply.
Also fixes a doc mismatch @v vs. a parameter named value.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-9-eblake@redhat.com>
It's already confusing that we have two very similar functions for
wrapping the parse of a 64-bit unsigned value, differing mainly on
whether they permit leading '-'. Adjust the signature of parse_uint()
and parse_uint_full() to be like all of qemu_strto*(): put the result
parameter last, use the same types (uint64_t and unsigned long long
have the same width, but are not always the same type), and mark
endptr const (this latter change only affects the rare caller of
parse_uint). Adjust all callers in the tree.
While at it, note that since cutils.c already includes:
QEMU_BUILD_BUG_ON(sizeof(int64_t) != sizeof(long long));
we are guaranteed that the result of parse_uint* cannot exceed
UINT64_MAX (or the build would have failed), so we can drop
pre-existing dead comparisons in opts-visitor.c that were never false.
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-8-eblake@redhat.com>
[eblake: Drop dead code spotted by Markus]
Signed-off-by: Eric Blake <eblake@redhat.com>
These two functions are subtly different, and not just because of
swapped parameter order. It took me adding better unit tests to
figure out why. Document the differences to make it more obvious to
developers trying to pick which one to use, as well as to aid in
upcoming semantic changes.
While touching the documentation, adjust a mis-statement: parse_uint
does not return -EINVAL on invalid base, but assert()s, like all the
other qemu_strto* functions that take a base argument.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-7-eblake@redhat.com>
While we were matching 32-bit strtol in qemu_strtoi, our use of a
64-bit parse was leaking through for some inaccurate answers in
qemu_strtoui in comparison to a 32-bit strtoul (see the unit test for
examples). The comment for that function even described what we have
to do for a correct parse, but didn't implement it correctly: since
strtoull checks for overflow against the wrong values and then
negates, we have to temporarily undo negation before checking for
overflow against our desired value.
Our int wrappers would be a lot easier to write if libc had a
guaranteed 32-bit parser even on platforms with 64-bit long.
Whether we parse C2x binary strings like "0b1000" is currently up to
what libc does; our unit tests intentionally don't cover that at the
moment, though.
Fixes: 473a2a331e ("cutils: add qemu_strtoi & qemu_strtoui parsers for int/unsigned int types", v2.12.0)
Signed-off-by: Eric Blake <eblake@redhat.com>
CC: qemu-stable@nongnu.org
Message-Id: <20230522190441.64278-6-eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
All callers now pass is_external=false to aio_set_fd_handler() and
aio_set_event_notifier(). The aio_disable_external() API that
temporarily disables fd handlers that were registered is_external=true
is therefore dead code.
Remove aio_disable_external(), aio_enable_external(), and the
is_external arguments to aio_set_fd_handler() and
aio_set_event_notifier().
The entire test-fdmon-epoll test is removed because its sole purpose was
testing aio_disable_external().
Parts of this patch were generated using the following coccinelle
(https://coccinelle.lip6.fr/) semantic patch:
@@
expression ctx, fd, is_external, io_read, io_write, io_poll, io_poll_ready, opaque;
@@
- aio_set_fd_handler(ctx, fd, is_external, io_read, io_write, io_poll, io_poll_ready, opaque)
+ aio_set_fd_handler(ctx, fd, io_read, io_write, io_poll, io_poll_ready, opaque)
@@
expression ctx, notifier, is_external, io_read, io_poll, io_poll_ready;
@@
- aio_set_event_notifier(ctx, notifier, is_external, io_read, io_poll, io_poll_ready)
+ aio_set_event_notifier(ctx, notifier, io_read, io_poll, io_poll_ready)
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230516190238.8401-21-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
vhost-user activity must be suspended during bdrv_drained_begin/end().
This prevents new requests from interfering with whatever is happening
in the drained section.
Previously this was done using aio_set_fd_handler()'s is_external
argument. In a multi-queue block layer world the aio_disable_external()
API cannot be used since multiple AioContext may be processing I/O, not
just one.
Switch to BlockDevOps->drained_begin/end() callbacks.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230516190238.8401-8-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Each vhost-user-blk request runs in a coroutine. When the BlockBackend
enters a drained section we need to enter a quiescent state. Currently
any in-flight requests race with bdrv_drained_begin() because it is
unaware of vhost-user-blk requests.
When blk_co_preadv/pwritev()/etc returns it wakes the
bdrv_drained_begin() thread but vhost-user-blk request processing has
not yet finished. The request coroutine continues executing while the
main loop thread thinks it is in a drained section.
One example where this is unsafe is for blk_set_aio_context() where
bdrv_drained_begin() is called before .aio_context_detached() and
.aio_context_attach(). If request coroutines are still running after
bdrv_drained_begin(), then the AioContext could change underneath them
and they race with new requests processed in the new AioContext. This
could lead to virtqueue corruption, for example.
(This example is theoretical, I came across this while reading the
code and have not tried to reproduce it.)
It's easy to make bdrv_drained_begin() wait for in-flight requests: add
a .drained_poll() callback that checks the VuServer's in-flight counter.
VuServer just needs an API that returns true when there are requests in
flight. The in-flight counter needs to be atomic.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230516190238.8401-7-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The VuServer object has a refcount field and ref/unref APIs. The name is
confusing because it's actually an in-flight request counter instead of
a refcount.
Normally a refcount destroys the object upon reaching zero. The VuServer
counter is used to wake up the vhost-user coroutine when there are no
more requests.
Avoid confusing by renaming refcount and ref/unref to in_flight and
inc/dec.
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230516190238.8401-6-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Since commit abe34282 ("win32: avoid mixing SOCKET and file descriptor
space"), we set HANDLE_FLAG_PROTECT_FROM_CLOSE on the socket FD, to
prevent closing the HANDLE with CloseHandle. This raises an exception
which under gdb is fatal, and qemu exits.
Let's catch the expected error instead.
Note: this appears to work, but the mingw64 macro is not well documented
or tested, and it's not obvious how it is meant to be used.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20230515132440.1025315-1-marcandre.lureau@redhat.com>
* Fix for a memory corruption due to an extra free
* Fix for a compile breakage
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Merge tag 'pull-vfio-20230524' of https://github.com/legoater/qemu into staging
vfio queue:
* Fix for a memory corruption due to an extra free
* Fix for a compile breakage
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* tag 'pull-vfio-20230524' of https://github.com/legoater/qemu:
util/vfio-helpers: Use g_file_read_link()
vfio/pci: Fix a use-after-free issue
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
When _FORTIFY_SOURCE=2, glibc version is 2.35, and GCC version is
12.1.0, the compiler complains as follows:
In file included from /usr/include/features.h:490,
from /usr/include/bits/libc-header-start.h:33,
from /usr/include/stdint.h:26,
from /usr/lib/gcc/aarch64-unknown-linux-gnu/12.1.0/include/stdint.h:9,
from /home/alarm/q/var/qemu/include/qemu/osdep.h:94,
from ../util/vfio-helpers.c:13:
In function 'readlink',
inlined from 'sysfs_find_group_file' at ../util/vfio-helpers.c:116:9,
inlined from 'qemu_vfio_init_pci' at ../util/vfio-helpers.c:326:18,
inlined from 'qemu_vfio_open_pci' at ../util/vfio-helpers.c:517:9:
/usr/include/bits/unistd.h:119:10: error: argument 2 is null but the corresponding size argument 3 value is 4095 [-Werror=nonnull]
119 | return __glibc_fortify (readlink, __len, sizeof (char),
| ^~~~~~~~~~~~~~~
This error implies the allocated buffer can be NULL. Use
g_file_read_link(), which allocates buffer automatically to avoid the
error.
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
Move the code from tcg/. The only use of these bits so far
is with respect to the atomicity of tcg operations.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Use cpuinfo_init() during init_accel(), and the variable cpuinfo
during test_buffer_is_zero_next_accel(). Adjust the logic that
cycles through the set of accelerators for testing.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Add a bit to indicate when VMOVDQU is also atomic if aligned.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Add cpuinfo.h for i386 and x86_64, and the initialization
for that in util/. Populate that with a slightly altered
copy of the tcg host probing code. Other uses of cpuid.h
will be adjusted one patch at a time.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
QEMU's event loop supports nesting, which means that event handler
functions may themselves call aio_poll(). The condition that triggered a
handler must be reset before the nested aio_poll() call, otherwise the
same handler will be called and immediately re-enter aio_poll. This
leads to an infinite loop and stack exhaustion.
Poll handlers are especially prone to this issue, because they typically
reset their condition by finishing the processing of pending work.
Unfortunately it is during the processing of pending work that nested
aio_poll() calls typically occur and the condition has not yet been
reset.
Disable a poll handler during ->io_poll_ready() so that a nested
aio_poll() call cannot invoke ->io_poll_ready() again. As a result, the
disabled poll handler and its associated fd handler do not run during
the nested aio_poll(). Calling aio_set_fd_handler() from inside nested
aio_poll() could cause it to run again. If the fd handler is pending
inside nested aio_poll(), then it will also run again.
In theory fd handlers can be affected by the same issue, but they are
more likely to reset the condition before calling nested aio_poll().
This is a special case and it's somewhat complex, but I don't see a way
around it as long as nested aio_poll() is supported.
Cc: qemu-stable@nongnu.org
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2186181
Fixes: c382706925 ("block: Mark bdrv_co_io_(un)plug() and callers GRAPH_RDLOCK")
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230502184134.534703-2-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
To simplify the code, rename coroutine-win32.c to match the option
passed to configure.
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
QEMU adds the path to glib.h to all compilation commands. This is simpler
due to the pervasive use of static_library, and was grandfathered in from
the previous Make-based build system. Until Meson 0.63 the only way to
do this was to detect glib in configure and use add_project_arguments,
but now it is possible to use add_project_dependencies instead.
gmodule is detected in a separate variable, with export enabled for
modules and disabled for plugin.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add new -run-with option with an async-teardown=on|off parameter. It is
visible in the output of query-command-line-options QMP command, so it
can be discovered and used by libvirt.
The option -async-teardown is now redundant, deprecate it.
Reported-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
Fixes: c891c24b1a ("os-posix: asynchronous teardown for shutdown on Linux")
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-Id: <20230505120051.36605-2-imbrenda@linux.ibm.com>
[thuth: Add curly braces to fix error with GCC 8.5, fix bug in deprecated.rst]
Signed-off-by: Thomas Huth <thuth@redhat.com>
There is no need for the AioContext lock in aio_wait_bh_oneshot().
It's easy to remove the lock from existing callers and then switch from
AIO_WAIT_WHILE() to AIO_WAIT_WHILE_UNLOCKED() in aio_wait_bh_oneshot().
Document that the AioContext lock should not be held across
aio_wait_bh_oneshot(). Holding a lock across aio_poll() can cause
deadlock so we don't want callers to do that.
This is a step towards getting rid of the AioContext lock.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230404153307.458883-1-stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Use a store-release when enqueuing a new call_rcu, and a load-acquire
when dequeuing; and read the tail after checking that node->next is
consistent, which is the standard message passing pattern and it is
clearer than mb_read/mb_set.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Some time after systemd documented LISTEN_PID and LISTEN_FDS for
socket activation, they later added LISTEN_FDNAMES; now documented at:
https://www.freedesktop.org/software/systemd/man/sd_listen_fds.html
In particular, look at the implementation of sd_listen_fds_with_names():
https://github.com/systemd/systemd/blob/main/src/libsystemd/sd-daemon/sd-daemon.c
If we ever pass LISTEN_PID=xxx and LISTEN_FDS=n to a child process,
but leave LISTEN_FDNAMES=... unchanged as inherited from our parent
process, then our child process using sd_listen_fds_with_names() might
see a mismatch in the number of names (unexpected -EINVAL failure), or
even if the number of names matches the values of those names may be
unexpected (with even less predictable results).
Usually, this is not an issue - the point of LISTEN_PID is to tell
systemd socket activation to ignore all other LISTEN_* if they were
not directed to this particular pid. But if we end up consuming a
socket directed to this qemu process, and later decide to spawn a
child process that also needs systemd socket activation, we must
ensure we are not leaking any stale systemd variables through to that
child. The easiest way to do this is to wipe ALL LISTEN_* variables
at the time we consume a socket, even if we do not yet care about a
LISTEN_FDNAMES passed in from the parent process.
See also https://lists.freedesktop.org/archives/systemd-devel/2023-March/048920.html
Thanks: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20230324153349.1123774-1-eblake@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
A BH callback can free the BH, causing a use-after-free in aio_bh_call.
Fix that by keeping a local copy of the re-entrancy guard pointer.
Buglink: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=58513
Fixes: 9c86c97f12 ("async: Add an optional reentrancy guard to the BH API")
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20230501141956.3444868-1-alxndr@bu.edu>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
* Update kernel headers to 6.3rc5
* Suppress GCC13 false positive in aio_bh_poll()
* Add new x86 feature bits
* Coverity fixes
* More steps towards removing qatomic_mb_set/read
* Fix reduced-phys-bits value for AMD SEV
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Merge tag 'for-upstream' of https://gitlab.com/bonzini/qemu into staging
* Fix compilation issues under Debian 10
* Update kernel headers to 6.3rc5
* Suppress GCC13 false positive in aio_bh_poll()
* Add new x86 feature bits
* Coverity fixes
* More steps towards removing qatomic_mb_set/read
* Fix reduced-phys-bits value for AMD SEV
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# gpg: Signature made Sat 29 Apr 2023 01:19:14 PM BST
# gpg: using RSA key F13338574B662389866C7682BFFBD25F78C7AE83
# gpg: issuer "pbonzini@redhat.com"
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>" [undefined]
# gpg: aka "Paolo Bonzini <pbonzini@redhat.com>" [undefined]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg: There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 46F5 9FBD 57D6 12E7 BFD4 E2F7 7E15 100C CD36 69B1
# Subkey fingerprint: F133 3857 4B66 2389 866C 7682 BFFB D25F 78C7 AE83
* tag 'for-upstream' of https://gitlab.com/bonzini/qemu:
cpus-common: stop using mb_set/mb_read
async: Suppress GCC13 false positive in aio_bh_poll()
tests: vhost-user-test: release mutex on protocol violation
Update linux headers to v6.3rc5
update-linux-headers.sh: Add missing kernel headers.
Fix libvhost-user.c compilation.
target/i386: Add support for PREFETCHIT0/1 in CPUID enumeration
target/i386: Add support for AVX-NE-CONVERT in CPUID enumeration
target/i386: Add support for AVX-VNNI-INT8 in CPUID enumeration
target/i386: Add support for AVX-IFMA in CPUID enumeration
target/i386: Add support for AMX-FP16 in CPUID enumeration
target/i386: Add support for CMPCCXADD in CPUID enumeration
i386/cpu: Update how the EBX register of CPUID 0x8000001F is set
i386/sev: Update checks and information related to reduced-phys-bits
qemu-options.hx: Update the reduced-phys-bits documentation
qapi, i386/sev: Change the reduced-phys-bits value from 5 to 1
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
GCC13 reports an error :
../util/async.c: In function ‘aio_bh_poll’:
include/qemu/queue.h:303:22: error: storing the address of local variable ‘slice’ in ‘*ctx.bh_slice_list.sqh_last’ [-Werror=dangling-pointer=]
303 | (head)->sqh_last = &(elm)->field.sqe_next; \
| ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
../util/async.c:169:5: note: in expansion of macro ‘QSIMPLEQ_INSERT_TAIL’
169 | QSIMPLEQ_INSERT_TAIL(&ctx->bh_slice_list, &slice, next);
| ^~~~~~~~~~~~~~~~~~~~
../util/async.c:161:17: note: ‘slice’ declared here
161 | BHListSlice slice;
| ^~~~~
../util/async.c:161:17: note: ‘ctx’ declared here
But the local variable 'slice' is removed from the global context list
in following loop of the same routine. Add a pragma to silent GCC.
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Tested-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20230420202939.1982044-1-clg@kaod.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Devices can pass their MemoryReentrancyGuard (from their DeviceState),
when creating new BHes. Then, the async API will toggle the guard
before/after calling the BH call-back. This prevents bh->mmio reentrancy
issues.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20230427211013.2994127-3-alxndr@bu.edu>
[thuth: Fix "line over 90 characters" checkpatch.pl error]
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Juan Quintela <quintela@redhat.com>
thread_pool_submit_aio() is always called on a pool taken from
qemu_get_current_aio_context(), and that is the only intended
use: each pool runs only in the same thread that is submitting
work to it, it can't run anywhere else.
Therefore simplify the thread_pool_submit* API and remove the
ThreadPool function parameter.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20230203131731.851116-5-eesposit@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Use qemu_get_current_aio_context() where possible, since we always
submit work to the current thread anyways.
We want to also be sure that the thread submitting the work is
the same as the one processing the pool, to avoid adding
synchronization to the pool list.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20230203131731.851116-4-eesposit@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This new helper fetches file system type for a fd. Only Linux is
implemented so far. Currently only tmpfs and hugetlbfs are defined,
but it can grow as needed.
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Fix use-after-free errors in the code path that called error_handle(). A
call to error_handle() will now either free the passed Error 'err' or
assign it to '*errp' if '*errp' is currently NULL. This ensures that 'err'
either has been freed or is assigned to '*errp' if this function returns.
Adjust the two callers of this function to not assign the 'err' to '*errp'
themselves, since this is now handled by error_handle().
Fixes: commit 3ffef1a55c ("error: add global &error_warn destination")
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-id: 20230406154347.4100700-1-stefanb@linux.ibm.com
qemu-user can hang in a multi-threaded fork. One common
reason is that when creating a TB, between fork and exec
we manipulate a GTree whose memory allocator (GSlice) is
not fork-safe.
Although POSIX does not mandate it, the system's allocator
(e.g. tcmalloc, libc malloc) is probably fork-safe.
Fix some of these hangs by using QTree, which uses the system's
allocator regardless of the Glib version that we used at
configuration time.
Tested with the test program in the original bug report, i.e.:
```
void garble() {
int pid = fork();
if (pid == 0) {
exit(0);
} else {
int wstatus;
waitpid(pid, &wstatus, 0);
}
}
void supragarble(unsigned depth) {
if (depth == 0)
return ;
std::thread a(supragarble, depth-1);
std::thread b(supragarble, depth-1);
garble();
a.join();
b.join();
}
int main() {
supragarble(10);
}
```
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/285
Reported-by: Valentin David <me@valentindavid.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Emilio Cota <cota@braap.org>
Message-Id: <20230205163758.416992-3-cota@braap.org>
[rth: Add QEMU_DISABLE_CFI for all callback using functions.]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
If another thread calls aio_set_fd_handler() while the IOThread event
loop is upgrading from ppoll(2) to epoll(7) then we might miss new
AioHandlers. The epollfd will not monitor the new AioHandler's fd,
resulting in hangs.
Take the AioHandler list lock while upgrading to epoll. This prevents
AioHandlers from changing while epoll is being set up. If we cannot lock
because we're in a nested event loop, then don't upgrade to epoll (it
will happen next time we're not in a nested call).
The downside to taking the lock is that the aio_set_fd_handler() thread
has to wait until the epoll upgrade is finished, which involves many
epoll_ctl(2) system calls. However, this scenario is rare and I couldn't
think of another solution that is still simple.
Reported-by: Qing Wang <qinwang@redhat.com>
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2090998
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Fam Zheng <fam@euphon.net>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230323144859.1338495-1-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
vhost_user_server_stop() uses AIO_WAIT_WHILE(). AIO_WAIT_WHILE()
requires that AioContext is only acquired once.
Since blk_exp_request_shutdown() already acquires the AioContext it
shouldn't be acquired again in vhost_user_server_stop().
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230323145853.1345527-1-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
