Re: [Qemu-devel] Re: [PATCH] Implement a virtio GPU transport

[Avi Kivity]

 On 10/27/2010 03:00 PM, Ian Molton wrote:
> On 19/10/10 11:39, Avi Kivity wrote:
> > On 10/19/2010 12:31 PM, Ian Molton wrote:
>
> > > > 2. should start with a patch to the virtio-pci spec to document what
> > > > you're doing
> > >
> > > Where can I find that spec?
> >
> > http://ozlabs.org/~rusty/virtio-spec/
>
> Ok, but I'm not patching that until theres been some review.

Well, I like to review an implementation against a spec.

> There are links to the associated qemu and guest OS changes in my 
> original email.
>
> > > It doesnt, at present... It could be changed fairly easily ithout
> > > breaking anything if that happens though.
> >
> > The hypervisor and the guest can be changed independently. The driver
> > should be coded so that it doesn't depend on hypervisor implementation
> > details.
>
> Fixed - updated patch tested and attached.
> +
> +       /* Transfer data */
> +       if (virtqueue_add_buf(vq, sg_list, o_page, i_page, gldata)>= 0) {
> +               virtqueue_kick(vq);
> +               /* Chill out until it's done with the buffer. */
> +               wait_for_completion(&gldata->done);
> +       }
> +

Better, but still unsatisfying.  If the server is busy, the caller would 
block.  I guess it's expected since it's called from ->fsync().  I'm not 
sure whether that's the best interface, perhaps aio_writev is better.

--
error compiling committee.c: too many arguments to function