Linux Virtualization - Oct 2010 - [Qemu-devel] Re: [PATCH] Implement a virtio GPU transport

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.

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.

-Ian
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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

On Wed, 27 Oct 2010 11:30:31 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.
Fair enough; it's a bit of a PITA to patch, so it makes sense to get the
details nailed down first.
> 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.
OK. FWIW, I think this is an awesome idea.  I understand others are skeptical,
but this seems simple and if it works and you're happy to maintain it
I'm
happy to let you do it :)

Cheers,
Rusty.