Re: [PATCH 1/3] vhost-vsock-pci: force virtio version 1

[Stefano Garzarella]

On Wed, Aug 19, 2020 at 01:55:42PM +0200, Cornelia Huck wrote:
> On Wed, 19 Aug 2020 12:51:54 +0200
> Stefano Garzarella <sgarzare@redhat.com> wrote:
> 
> > Commit 9b3a35ec82 ("virtio: verify that legacy support is not
> > accidentally on") added a safety checks that requires to set
> 
> Nit: s/checks/check/ (also in patch 2)

I'll fix.

> 
> > 'disable-legacy=on' on vhost-vsock-pci device:
> > 
> >     $ ./qemu-system-x86_64 ... -device vhost-vsock-pci,guest-cid=5
> >         qemu-system-x86_64: -device vhost-vsock-pci,guest-cid=5:
> >         device is modern-only, use disable-legacy=on
> > 
> > virtio-vsock was introduced after the release of VIRTIO 1.0
> > specifications, so it should be 'modern-only'.
> > In addition Cornelia verified that forcing a legacy mode on
> > vhost-vsock-pci device using x86-64 host and s390x guest, so with
> > different endianness, produces strange behaviours.
> > 
> > This patch forces virtio version 1 and remove 'transitional_name'
> > properties removing the need to specify 'disable-legacy=on' on
> 
> "removes the 'transitional_name' property" ?

It is better, I'll fix.

> 
> (Unless you want to merge with patch 2, which might make sense.)

I left seprated because vhost-user-vsock-pci was introduced in QEMU 5.1,
so I wanted to make it easier to backport on others stable branches.
(I'm not sure if we continue to support 4.2).

Does it make sense to keep them separated?

> 
> > vhost-vsock-pci device.
> > 
> > Cc: qemu-stable@nongnu.org
> > Reported-by: Qian Cai <caiqian@redhat.com>
> > Reported-by: Qinghua Cheng <qcheng@redhat.com>
> > Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1868449
> > Suggested-by: Cornelia Huck <cohuck@redhat.com>
> > Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> > ---
> >  hw/virtio/vhost-vsock-pci.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
> 

Thanks,
Stefano