[virtio-dev] Re: [virtio-comment] [PATCH 5/5] virtio-pci: implement VIRTIO_F_QUEUE_STATE

Jason Wang
2023-09-19T04:35:39Z

On Sun, Sep 17, 2023 at 1:25 PM Parav Pandit <parav@nvidia.com> wrote:
>
>
> > From: Jason Wang <jasowang@redhat.com>
> > Sent: Thursday, September 14, 2023 8:41 AM
> >
> > On Wed, Sep 13, 2023 at 12:37 PM Parav Pandit <parav@nvidia.com> wrote:
> > >
> > >
> > >
> > > > From: Zhu, Lingshan <lingshan.zhu@intel.com>
> > > > Sent: Wednesday, September 13, 2023 9:51 AM
> > >
> > > > we plan to implement a self-contain solution
> > > Make sure that works with device reset and FLR.
> >
> > We don't need to do that. It's out of the spec.
> >
> It is not. For the PCI member device, it needs to work reliably.

We never mentioned FLR in the PCI transport layer before and vendors
have produced tons of hardware PCI devices for several years.

If it's important, please describe it in detail in your series but it doesn't.

> Not doing means it relies on the trap+emulation, hence it just cannot complete.
> And it is ok to me.
> I just wont claim that trap+emulation is _complete_ method.
>
> > > And if not, explain that it is for mediation mode related tricks.
> >
> > It's not the tricks and again, it's not mediation but trap and emulation. It's the
> > fundamental methodology used in virtualization, so does the virtio spec.
>
> Not the virto spec of 2023 and more for new features.
> The base for virtio spec 1.x was 0.9.5, but not the QEMU or other mediation based software AFAIK.

Are you saying those new features will not be suitable for software
devices? If yes, please explain why.

Or are you saying the virtio spec is not capable for hardware devices?

Thanks