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

[Roman Kagan]

On Tue, Aug 30, 2016 at 03:54:39PM -0400, 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").

That did it, thanks!

Roman.