Re: [Qemu-devel] qemu seabios issue with vhost-scsi

[Badari Pulavarty <pbadari@us.ibm.com>]

On 05/23/2013 06:32 AM, Stefan Hajnoczi wrote:
> On Thu, May 23, 2013 at 11:48 AM, Gleb Natapov <gleb@redhat.com> wrote:
>> On Thu, May 23, 2013 at 08:53:55AM +0800, Asias He wrote:
>>> On Wed, May 22, 2013 at 05:36:08PM -0700, Badari wrote:
>>>> Hi,
>>>>
>>>> While testing vhost-scsi in the current qemu git, ran into an earlier issue
>>>> with seabios. I had to disable scsi support in seabios to get it working.
>>>>
>>>> I was hoping this issue got resolved when vhost-scsi support got
>>>> merged into qemu. Is this still being worked on ?
>>> Hmm, can you try seabios.git? Not sure if seabios shipped by qemu picked
>>> up the fixes for vhost-scsi.
>>>
>> Nothing in seabios should crash qemu.
> Agreed.  I'm pretty sure it's the scenario that I posted in my other
> reply to this thread.
>
> The common virtio-scsi code in QEMU should guard against this.  In
> virtio-blk data plane I hit a similar case and ended up starting the
> data plane thread (equivalent to vhost here) *before* the status
> register is set to DRIVER_OK.
>

Thats exactly what my debug in vhost_scsi_set_status() shows.

set status started 0 val 0
set status started 0 val 0
set status started 0 val 0
set status started 0 val 0
set status started 0 val 0
set status started 0 val 3
Program received signal SIGSEGV, Segmentation fault.

We never got a chance to call vhost_scsi_start() as we are waiting
for DRIVER_OK.

Thanks,
Badari