Re: [virtio-comment] [PATCH RFC] virtio: introduce VIRTIO_F_DEVICE_STOP

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Dec 25, 2020 at 02:45:28PM +0800, Jason Wang wrote:
> > I tend to say, that from a perspective of the driver, all requests that
> > are available, and not yet used, are in-flight. So we have to be very
> > careful when wording this requirement, to avoid misunderstandings. I
> > don't think the first RFC is good enough. I will think some more about
> > this.
> 
> 
> Yes, I agree. The problem is that the spec doesn't describe how device work,
> so if we want to be more accurate, it might require some work not only for
> stop but also for e.g reset (something like in flight has been used by the
> spec in that case).

You probably mean the DEVICE_NEEDS_RESET description, right?

	For example, the driver can't assume requests in flight will be
	completed if DEVICE_NEEDS_RESET is set, nor can it assume that
	they have not been completed.  A good implementation will try to
	recover by issuing a reset.

yes, DEVICE_NEEDS_RESET is unfortunately underspecified which likely
is related to the fact it is not widely implemented.

-- 
MST