Hello,
On 02/23/2017 01:32 AM, Alex Williamson wrote:
> On Wed, 22 Feb 2017 10:03:56 +0100
> Paolo Bonzini <pbonz...@redhat.com> wrote:
>
>> On 21/02/2017 18:54, Laszlo Ersek wrote:
>>> Actually, QEMU segfaults. From the dmesg:
>>>
>>> [Tue Feb 21 18:47:28 2017] CPU 0/KVM[8298]: segfault at 48 ip
>>> 00007fcb5dd02105 sp 00007fcb49efc270 error 4 in
>>> qemu-system-x86_64[7fcb5dae3000+905000]
>>>
>>> Complete backtrace below. (Thread 11 seems to be the one
>>> segfaulting.)
>>
>> Indeed. It's the virtio-blk device that is segfaulting, please try
>> this one liner (haven't reproduced it, but it seems obvious with the
>> backtrace and some sleep).
>
> I hit this as well, the patch below resolves it.
I still have migration issues with this patch on ppc, which fails
on the target guest with :
qemu-system-ppc64: VQ 0 size 0x80 < last_avail_idx 0xe1e - used_idx 0x0
qemu-system-ppc64: Failed to load virtio-blk:virtio
qemu-system-ppc64: error while loading state for instance 0x0 of device
'pci@800000020000000:01.0/virtio-blk'
qemu-system-ppc64: load of migration failed: Operation not permitted
Thanks,
C.
> Tested-by: Alex Williamson <alex.william...@redhat.com>
>
>> commit c1aa478c7181c543606ca81404c59e126d66213d
>> Author: Paolo Bonzini <pbonz...@redhat.com>
>> Date: Wed Feb 22 10:02:37 2017 +0100
>>
>> virtio: check for vring setup in virtio_queue_empty
>>
>> If the vring has not been set up, there is nothing in the virtqueue.
>> virtio_queue_host_notifier_aio_poll calls virtio_queue_empty even in
>> this case; we have to filter it out just like virtio_queue_notify_aio_vq.
>>
>> Reported-by: Gerd Hoffmann <kra...@redhat.com>
>> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
>>
>> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
>> index 23483c7..e487e36 100644
>> --- a/hw/virtio/virtio.c
>> +++ b/hw/virtio/virtio.c
>> @@ -2291,7 +2291,7 @@ static bool virtio_queue_host_notifier_aio_poll(void
>> *opaque)
>> VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
>> bool progress;
>>
>> - if (virtio_queue_empty(vq)) {
>> + if (!vq->vring.desc || virtio_queue_empty(vq)) {
>> return false;
>> }
>>
>>
>
>
