Re: [Qemu-stable] [Qemu-devel] [PATCH] virtio-scsi: fix object check failure

[Ming Lei]

On Wed, Jun 18, 2014 at 11:06 PM, Paolo Bonzini <address@hidden> wrote:
> Il 18/06/2014 17:02, Paolo Bonzini ha scritto:
>
>> Il 18/06/2014 16:18, Ming Lei ha scritto:
>>>>
>>>> > This should never be triggered by vhost-scsi.  Perhaps a bug in the
>>>> kernel?
>>>
>>> It can be triggered with rmmod, system suspend, reboot...
>>
>>
>> Yes, but it should not.
>>
>> What happens if you change VHOST_SCSI_VQ_NUM_FIXED from 2 to 3?
>
>
> Sorry, brain fart here.  The number of interrupts in virtio-scsi is queues+3
> because of the configuration interrupt.  This does not apply here.
>
> Anyway, vhost-scsi passes the number of virtqueues correctly to the kernel.
>
> QEMU might be triggering this because, when vhost is stopped, the queue is
> still not empty (as expected, since it's a receive queue).
>
> Can you check that this is the case?

Yes, that is the case.

>
> If so, patching QEMU is correct, but you need to change VIRTIO_SCSI(vdev) to
> VIRTIO_SCSI_COMMON(vdev), and move events_dropped from VirtIOSCSI to
> VirtIOSCSICommon.

This approach should be better.

Thanks,
--
Ming Lei