Re: [Qemu-devel] [PATCH RFC for-2.2] virtio-blk: force 1st s/g to match header

[Peter Maydell]

On 28 November 2014 at 11:43, Stefan Hajnoczi <address@hidden> wrote:
> Right, the test case explicitly tests different descriptor layouts,
> even though virtio-blk-pci does not set the ANY_LAYOUT feature bit.
>
> Either the test case needs to check ANY_LAYOUT before using the
> 2-descriptor layout or it needs to expect QEMU to refuse (in this case
> exit(1), which is not very graceful).
>
> The quick fix is to skip the 2-descriptor layout tests and re-enable
> them once virtio-blk actually supports ANY_LAYOUT.  Any objections?

So what do we want to do with this for 2.2? We have I think
two choices:
 (1) say that this isn't causing problems in practice, and defer all
 this to 2.3
 (2) add something like this patch plus fix the 'make check' tests
 (but turning "maybe something misbehaves" into "qemu definitely
 blows up and exits" doesn't seem like a great improvement to me)

I started looking at virtio-blk initially because I wasn't sure
if we should fix the virtio-net issue in the core virtio code.
But since we've decided not to do that, whether virtio-blk's
problems are release-blockers or not is something that we can
decide on their own merits.

My current thought is that we don't need to address this for 2.2;
is there something I'm missing that means we shouldn't defer to 2.3?

thanks
-- PMM