Re: [Qemu-devel] [PATCH 0/2] virtio: fix VirtQueue->inuse field

[Denis V. Lunev]

On 08/30/2016 10:54 PM, Stefan Hajnoczi wrote:
> On Mon, Aug 22, 2016 at 10:00 AM, Denis V. Lunev
> <address@hidden> wrote:
>> On 08/15/2016 08:54 AM, Stefan Hajnoczi wrote:
>>> The VirtQueue->inuse field is not always updated correctly.  These patches
>>> fix
>>> it.
>>>
>>> Originally this series was called "virtio-balloon: fix stats vq migration"
>>> but
>>> Ladi Prosek posted a nicer fix called "balloon: Fix failure of updating
>>> guest
>>> memory status".  I dropped the virtio-balloon patches.
>>>
>>> Changes from previous series:
>>>   * Missing comma in error formatting [Fam]
>>>   * virtio_descard() -> virtio_discard() [Michael]
>>>   * Multi-line comment style [Cornelia]
>>>
>>> Stefan Hajnoczi (2):
>>>    virtio: recalculate vq->inuse after migration
>>>    virtio: decrement vq->inuse in virtqueue_discard()
>>>
>>>   hw/virtio/virtio.c | 16 ++++++++++++++++
>>>   1 file changed, 16 insertions(+)
>>>
>> these patches break 'make check' with the following:
>>
>> GTESTER check-qtest-x86_64
>> Warning: path not on HugeTLBFS: /tmp/vhost-test-hRYeTb
>> Warning: path not on HugeTLBFS: /tmp/vhost-test-hRYeTb
>> Warning: path not on HugeTLBFS: /tmp/vhost-test-hRYeTb
>> qemu-system-x86_64: VQ 1 size 0x100 < last_avail_idx 0x0 - used_idx 0x1
>> qemu-system-x86_64: error while loading state for instance 0x0 of device
>> '0000:00:03.0/virtio-net'
>> qemu-system-x86_64: load of migration failed: Operation not permitted
>> Broken pipe
>> qemu-system-x86_64: Failed to read msg header. Read 0 instead of 12.
>> Original request 11.
>> GTester: last random seed: R02S122f07a3fc35cfd5b0204e3eb45c61e6
>> qemu-system-x86_64: Failed to read msg header. Read 0 instead of 12.
>> Original request 11.
>> Warning: path not on HugeTLBFS: /tmp/vhost-test-60WtDz
>> blkdebug: Suspended request 'A'
>> blkdebug: Resuming request 'A'
>> main-loop: WARNING: I/O thread spun for 1000 iterations
>> main-loop: WARNING: I/O thread spun for 1000 iterations
>> /home/den/src/git/qemu/tests/Makefile:400: recipe for target
>> 'check-qtest-x86_64' failed
>> make: *** [check-qtest-x86_64] Error 1
>> iris ~/src/git/qemu $
>>
>> Sorry, if I have missed the fix in the list.
> I hit this issue when backporting to a QEMU 2.3-based source tree.
> This doesn't happen in qemu.git/master.
>
> To save anyone doing a backport a lot of time:
>
> If you enable vhost-user-test in a QEMU 2.3-based source tree with the
> migration test case, make sure you also backport
> 8c56c1a592b5092d91da8d8943c17777d6462a6f ("memory: emulate
> ioeventfd").
>
> Stefan
thanks a lot! We will give this a try tomorrow.

Den