The statistics are now available through device properties via a
polling mechanism. First a client has to enable polling, then it
can query available stats.
Polling is enabled by setting an update interval (in seconds)
to a property named guest-stats-polling-interval, like this:
{ "execute": "qom-set",
"arguments": { "path": "/machine/peripheral-anon/device[1]",
"property": "guest-stats-polling-interval", "value": 4 } }
Then the available stats can be retrieved by querying the
guest-stats property. The returned object is a dict containing
all available stats. Example:
{ "execute": "qom-get",
"arguments": { "path": "/machine/peripheral-anon/device[1]",
"property": "guest-stats" } }
{
"return": {
"stats": {
"stat-swap-out": 0,
"stat-free-memory": 844943360,
"stat-minor-faults": 219028,
"stat-major-faults": 235,
"stat-total-memory": 1044406272,
"stat-swap-in": 0
},
"last-update": 1358529861
}
}
Please, check the next commit for full documentation.
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Next commit will re-enable balloon stats with a different interface, but
this old code conflicts with it. Let's drop it.
It's important to note that the QMP and HMP interfaces are also dropped
by this commit. That shouldn't be a problem though, because:
1. All QMP fields are optional
2. This feature has always been disabled
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
* mjt/mjt-iov2:
rewrite iov_send_recv() and move it to iov.c
cleanup qemu_co_sendv(), qemu_co_recvv() and friends
export iov_send_recv() and use it in iov_send() and iov_recv()
rename qemu_sendv to iov_send, change proto and move declarations to iov.h
change qemu_iovec_to_buf() to match other to,from_buf functions
consolidate qemu_iovec_copy() and qemu_iovec_concat() and make them consistent
allow qemu_iovec_from_buffer() to specify offset from which to start copying
consolidate qemu_iovec_memset{,_skip}() into single function and use existing iov_memset()
rewrite iov_* functions
change iov_* function prototypes to be more appropriate
virtio-serial-bus: use correct lengths in control_out() message
Conflicts:
tests/Makefile
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
After setting a balloon target value, applications have to
continually poll 'query-balloon' to determine whether the
guest has reacted to this request. The virtio-balloon backend
knows exactly when the guest has reacted though, and thus it
is possible to emit a JSON event to tell the mgmt application
whenever the guest balloon changes.
This introduces a new 'qemu_balloon_changed()' API which is
to be called by balloon driver backends, whenever they have
a change in balloon value. This takes the 'actual' balloon
value, as would be found in the BalloonInfo struct.
The qemu_balloon_change API emits a JSON monitor event which
looks like:
{"timestamp": {"seconds": 1337162462, "microseconds": 814521},
"event": "BALLOON_CHANGE", "data": {"actual": 944766976}}
* balloon.c, balloon.h: Introduce qemu_balloon_changed() for
emitting balloon change events on the monitor
* hw/virtio-balloon.c: Invoke qemu_balloon_changed() whenever
the guest changes the balloon actual value
* monitor.c, monitor.h: Define QEVENT_BALLOON_CHANGE
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reorder arguments to be more natural, readable and
consistent with other iov_* functions, and change
argument names, from:
iov_from_buf(iov, iov_cnt, buf, iov_off, size)
to
iov_from_buf(iov, iov_cnt, offset, buf, bytes)
The result becomes natural English:
copy data to this `iov' vector with `iov_cnt'
elements starting at byte offset `offset'
from memory buffer `buf', processing `bytes'
bytes max.
(Try to read the original prototype this way).
Also change iov_clear() to more general iov_memset()
(it uses memset() internally anyway).
While at it, add comments to the header file
describing what the routines actually does.
The patch only renames argumens in the header, but
keeps old names in the implementation. The next
patch will touch actual code to match.
Now, it might look wrong to pay so much attention
to so small things. But we've so many badly designed
interfaces already so the whole thing becomes rather
confusing or error prone. One example of this is
previous commit and small discussion which emerged
from it, with an outcome that the utility functions
like these aren't well-understdandable, leading to
strange usage cases. That's why I paid quite some
attention to this set of functions and a few
others in subsequent patches.
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Please, note that some of the code supporting memory statistics is
still around (eg. virtio_balloon_receive_stats() and reset_stats()).
Also, the qmp_query_balloon() function is synchronous and thus doesn't
make any use of the (not fully working) monitor's asynchronous command
support (the old non-qapi implementation did).
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Adding a 2nd balloon device after unplugging the first one doesn't work.
Also, the 'info balloon' command should indicate an error mentioning no
balloon device is registered after unplug.
Reproduction steps given by Shaolong Hu:
(qemu) info balloon
Device 'balloon' has not been activated by the guest
(qemu) device_add virtio-balloon-pci,id=balloon1
(qemu) info balloon
balloon: actual=4096
(qemu) balloon 2048
(qemu) info balloon
balloon: actual=2048
(qemu) device_del balloon1
(qemu) info balloon
balloon: actual=4096
(qemu) balloon 2048
(qemu) info balloon
balloon: actual=4096
(qemu) device_del balloon1
Device 'balloon1' not found
(qemu) device_add virtio-balloon-pci,id=balloon1
Another balloon device already registered
Device 'virtio-balloon-pci' could not be initialized
(qemu) device_add virtio-balloon-pci,id=balloon2
Another balloon device already registered
Device 'virtio-balloon-pci' could not be initialized
Reported-by: Shaolong Hu <shu@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Migrating after unplugging a virtio-balloon device resulted in an error
message on the destination:
Unknown savevm section or instance '0000:00:04.0/virtio-balloon' 0
load of migration failed
Fix this by unregistering the section on device unplug.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Add an exit handler that will free up RAM after a virtio-balloon device
is unplugged.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Multiple balloon registrations are not allowed; check if the
registration with the qemu balloon api succeeded. If not, fail the
device init.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Passing on '0' as ballooning target to indicate retrieval of stats is
bad API. It also makes 'balloon 0' in the monitor cause a segfault.
Have two different functions handle the different functionality instead.
Detailed explanation from Markus's review:
1. do_info_balloon() is an info_async() method. It receives a callback
with argument, to be called exactly once (callback frees the
argument). It passes the callback via qemu_balloon_status() and
indirectly through qemu_balloon_event to virtio_balloon_to_target().
virtio_balloon_to_target() executes its balloon stats half. It
stores the callback in the device state.
If it can't send a stats request, it resets stats and calls the
callback right away.
Else, it sends a stats request. The device model runs the callback
when it receives the answer.
Works.
2. do_balloon() is a cmd_async() method. It receives a callback with
argument, to be called when the command completes. do_balloon()
calls it right before it succeeds. Odd, but should work.
Nevertheless, it passes the callback on via qemu_ballon() and
indirectly through qemu_balloon_event to virtio_balloon_to_target().
a. If the argument is non-zero, virtio_balloon_to_target() executes
its balloon half, which doesn't use the callback in any way.
Odd, but works.
b. If the argument is zero, virtio_balloon_to_target() executes its
balloon stats half, just like in 1. It either calls the callback
right away, or arranges for it to be called later.
Thus, the callback runs twice: use after free and double free.
Test case: start with -S -device virtio-balloon, execute "balloon 0" in
human monitor. Runs the callback first from virtio_balloon_to_target(),
then again from do_balloon().
Reported-by: Mike Cao <bcao@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Separate out the code to retrieve balloon info from the code that sets
balloon values.
This will be used to separate the two callbacks from balloon.c and help
cope with 'balloon 0' on the monitor. Currently, 'balloon 0' causes a
segfault in monitor_resume().
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
The specification for the virtio balloon device requres that the values
in the config space be encoded little-endian. This differs from most
virtio things, where guest-native endian is the norm.
Currently, the qemu virtio-balloon code correctly makes the conversion
on get_config(), but doesn't on set_config for the 'actual' field. The
kernel driver, on the other hand, correctly converts when setting the
actual field, but does not convert when reading the config space. The
upshot is that virtio-balloon will only work correctly if both host and
guest are LE, making all the conversions nops.
This patch corrects the qemu side, correctly doing host-native <-> LE
conversions when accessing the config space. This won't break any setups
that aren't already broken, and fixes the case of BE host, LE guest.
Fixing the BE guest case will require kernel fixes as well.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
The addition of memory stats reporting to the virtio balloon causes
the 'info balloon' command to become asynchronous. This is a regression
because in some cases it can hang the user monitor.
This is an alternative to Adam Litke's patch. Adam's patch disabled the
corresponding (guest-visible) virtio feature bit, causing issues for migration.
Original discussion is available at:
http://marc.info/?l=qemu-devel&m=128448124328314&w=2
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Acked-by: Adam Litke <agl@us.ibm.com
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
vl.c has a Sun-specific hack to supply a prototype for madvise(),
but the call site has apparently moved to arch_init.c.
Haiku doesn't implement madvise() in favor of posix_madvise().
OpenBSD and Solaris 10 don't implement posix_madvise() but madvise().
MinGW implements neither.
Check for madvise() and posix_madvise() in configure and supply qemu_madvise()
as wrapper. Prefer madvise() over posix_madvise() due to flag availability.
Convert all callers to use qemu_madvise() and QEMU_MADV_*.
Note that on Solaris the warning is fixed by moving the madvise() prototype,
not by qemu_madvise() itself. It helps with porting though, and it simplifies
most call sites.
v7 -> v8:
* Some versions of MinGW have no sys/mman.h header. Reported by Blue Swirl.
v6 -> v7:
* Adopt madvise() rather than posix_madvise() semantics for returning errors.
* Use EINVAL in place of ENOTSUP.
v5 -> v6:
* Replace two leftover instances of POSIX_MADV_NORMAL with QEMU_MADV_INVALID.
Spotted by Blue Swirl.
v4 -> v5:
* Introduce QEMU_MADV_INVALID, suggested by Alexander Graf.
Note that this relies on -1 not being a valid advice value.
v3 -> v4:
* Eliminate #ifdefs at qemu_advise() call sites. Requested by Blue Swirl.
This will currently break the check in kvm-all.c by calling madvise() with
a supported flag, which will not fail. Ideas/patches welcome.
v2 -> v3:
* Reuse the *_MADV_* defines for QEMU_MADV_*. Suggested by Alexander Graf.
* Add configure check for madvise(), too.
Add defines to Makefile, not QEMU_CFLAGS.
Convert all callers, untested. Suggested by Blue Swirl.
* Keep Solaris' madvise() prototype around. Pointed out by Alexander Graf.
* Display configure check results.
v1 -> v2:
* Don't rely on posix_madvise() availability, add qemu_madvise().
Suggested by Blue Swirl.
Signed-off-by: Andreas Färber <afaerber@opensolaris.org>
Cc: Blue Swirl <blauwirbel@gmail.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
When available, we'd like to be able to access the DeviceState
when registering a savevm. For buses with a get_dev_path()
function, this will allow us to create more unique savevm
id strings.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
iov_to_buf() puts the buffer contents in the iov in a linearized buffer.
iov_size() gets the length of the contents in the iov.
The iov_to_buf() function is the memcpy_to_iovec() function that was
used in virtio-ballon.c.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Beginning with its introduction, the virtio balloon has had an overflow error
that causes 'info balloon' to misreport the actual memory size when the balloon
itself becomes larger than 4G. Use a cast when converting dev->actual from
pages to kB to prevent overflows.
Before:
(qemu) info balloon
balloon: actual=5120
(qemu) balloon 1025
(qemu) info balloon
balloon: actual=1025
(qemu) balloon 1024
(qemu) info balloon
balloon: actual=5120
After:
(qemu) info balloon
balloon: actual=5120
(qemu) balloon 1025
(qemu) info balloon
balloon: actual=1025
(qemu) balloon 1024
(qemu) info balloon
balloon: actual=1024
Signed-off-by: Adam Litke <agl@us.ibm.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
When working with the VM state (for loadvm/savevm and migration), it is not
valid to load and store pointers since the validity of those pointers cannot be
assured in the new qemu address space. Therefore, virtio_balloon_save() and
virtio_balloon_load() must not handle the stats-related fields in struct
VirtIOBalloon.
If a memory stats request is in-flight at the time of a migration or savevm,
the request will not complete and should be resubmitted once migration or
loadvm completes. Note that this extremely small race window can only be
triggered using QMP so it is not possible to hang the user monitor.
Signed-off-by: Adam Litke <agl@us.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
When using ballooning to manage overcommitted memory on a host, a system for
guests to communicate their memory usage to the host can provide information
that will minimize the impact of ballooning on the guests. The current method
employs a daemon running in each guest that communicates memory statistics to a
host daemon at a specified time interval. The host daemon aggregates this
information and inflates and/or deflates balloons according to the level of
host memory pressure. This approach is effective but overly complex since a
daemon must be installed inside each guest and coordinated to communicate with
the host. A simpler approach is to collect memory statistics in the virtio
balloon driver and communicate them directly to the hypervisor.
Signed-off-by: Adam Litke <agl@us.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Add feature bits as properties to virtio. This makes it possible to e.g. define
machine without indirect buffer support, which is required for 0.10
compatibility, or without hardware checksum support, which is required for 0.11
compatibility. Since default values for optional features are now set by qdev,
get_features callback has been modified: it sets non-optional bits, and clears
bits not supported by host.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
In the very least, a change like this requires discussion on the list.
The naming convention is goofy and it causes a massive merge problem. Something
like this _must_ be presented on the list first so people can provide input
and cope with it.
This reverts commit 99a0949b72.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This patch adds and uses #defines for PCI device classes and subclases,
using a new pci_config_set_class() function, similar to the recently
added pci_config_set_vendor_id() and pci_config_set_device_id().
Change since v1: fixed compilation of hw/sun4u.c
Signed-off-by: Stuart Brady <stuart.brady@gmail.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6491 c046a42c-6fe2-441c-8c8c-71466251a162
A subsystem vendor ID of zero isn't allowed, so we use our
default ID.
Gerd points out that although the PCI subsystem vendor ID is
treated by the guest as the virtio vendor ID:
/* we use the subsystem vendor/device id as the virtio vendor/device
* id. this allows us to use the same PCI vendor/device id for all
* virtio devices and to identify the particular virtio driver by
* the subsytem ids */
vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
vp_dev->vdev.id.device = pci_dev->subsystem_device;
it looks like only the device ID is used right now:
# grep virtio modules.alias
alias virtio:d00000001v* virtio_net
alias virtio:d00000002v* virtio_blk
alias virtio:d00000003v* virtio_console
alias virtio:d00000004v* virtio-rng
alias virtio:d00000005v* virtio_balloon
alias pci:v00001AF4d*sv*sd*bc*sc*i* virtio_pci
alias virtio:d00000009v* 9pnet_virtio
so setting the subsystem vendor id to something != zero shouldn't cause
trouble.
Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6440 c046a42c-6fe2-441c-8c8c-71466251a162
Use the defines added by the previous patch in the virtio drivers.
Also remove the pointless vendor and device args from the
virtio_blk_init() function.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5987 c046a42c-6fe2-441c-8c8c-71466251a162
This adds a VirtIO based balloon driver. It uses madvise() to actually balloon
the memory when possible.
Until 2.6.27, KVM forced memory pinning so we must disable ballooning unless the
kernel actually supports it when using KVM. It's always safe when using TCG.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5874 c046a42c-6fe2-441c-8c8c-71466251a162
