Re: [PATCH V2 1/2] virtio: introduce virtqueue state as basic facility

[Jason Wang <jasowang@redhat.com>]

在 2021/7/6 下午8:27, Cornelia Huck 写道:
> On Tue, Jul 06 2021, Jason Wang <jasowang@redhat.com> wrote:
>
> > This patch adds new device facility to save and restore virtqueue
> > state. The virtqueue state is split into two parts:
> >
> > - The available state: The state that is used for read the next
> >    available buffer.
> > - The used state: The state that is used for making buffer used.
> >
> > Note that, there could be devices that is required to set and get the
> > requests that are being processed by the device. I leave such API to
> > be device specific.
> >
> > This facility could be used by both migration and device diagnostic.
> >
> > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > ---
> >   content.tex | 117 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> >   1 file changed, 117 insertions(+)
> > +\devicenormative{\subsection}{Virtqueue State}{Basic Facilities of a Virtio Device / Virtqueue State}
> > +
> > +If VIRTIO_F_RING_STATE has not been negotiated, a device MUST ingore
> > +the read and write to the virtqueue state.
> > +
> > +If VIRTIO_F_RING_STATE has been negotiated:
> > +\begin{itemize}
> > +\item A device SHOULD ignore the write to the virtqueue state if the
> > +FEATURE_OK status bit is not set.
> > +\item A device SHOULD ignore the write to the virtqueue state if the
> > +DRIVER_OK status bit is set.
> > +\end{itemize}
> > +
> > +If VIRTIO_F_RING_STATE has been negotiated, a device MAY has its
> > +device-specific way for the driver to set and get extra virtqueue
> > +states such as in flight requests.
> Maybe better
>
> "If VIRTIO_F_RING_STATE has been negotiated, a device MAY provide a
> device-specific mechanism to set and get extra virtqueue states such as
> in flight reqeuests."
>
> If a device type supports this facility, does it imply that it is always
> present when VIRTIO_RING_STATE has been negotiated?


It's not, it's device specific.


> I guess it could
> define further device-specific features to make it more configurable.


Yes, I can clarify this in the next version.

Thanks


>