Hi again Daniel. I have a follow up question. Can you help me
understand how I can declare this "outputs" property?
-device '{"driver":"virtio-vga",
"max_outputs":2,
"id":"vga",
"outputs":[
{
"name":"AAA",
},
{
"name":"BBB",
},
]}'
I thought DEFINE_PROP_ARRAY would do it, but I can't tell what PropertyInfo
implementation I should pass. All of the PropertyInfo implementations I can
find use scalar types, or simple text decoding. I am wondering if I am
missing
some sort of "JSON" encoding capabilities that can happen behind the scenes.
On Tue, Nov 26, 2024 at 4:07 PM Andrew Keesler <[email protected]> wrote:
> Thanks, Daniel. We'll get this patch updated and send it out again.
>
> > it makes sense to allow for a data structure
>
> Whoops, I misread your original message - data structure SGTM.
>
> On Tue, Nov 26, 2024 at 11:04 AM Daniel P. Berrangé <[email protected]>
> wrote:
>
>> On Mon, Nov 25, 2024 at 03:54:40PM -0500, Andrew Keesler wrote:
>> > I follow what you are saying. I misunderstood what a "display" was in
>> the
>> > domain of QEMU. Yes, this makes more sense now.
>> >
>> > > the user should give names for every output at startup
>> >
>> > I see DEFINE_PROP_ARRAY exists. I can use that to define the new
>> "outputs"
>> > property. Any reason that each "output" would ever need to be an object
>> > (rather than just a string)? Nothing comes to mind, I'm just taking a
>> second
>> > to think about API forwards compatibility.
>>
>> Currently we have 'xres' and 'yres' properties set against the device
>> for virtio-gpu.
>>
>> If we're going to extend it to allow the name of each "output" head
>> to be configured, it makes sense to allow for a data structure that
>> will let us also cnofigure xres & yres per output.
>>
>> Hence, I thought it would make more sense to have an array of structs,
>> rather than the simpler array of strings, which will let us set any
>> amount of per-output config data we might want in future.
>>
>> NB, I'm not asking you to wire up support for xres/yres per output,
>> just that we anticipate it as a possibility.
>>
>> > > upto whatever they said for "max_outputs"
>> >
>> > Where is the best place to perform this validation? I would imagine we
>> would
>> > want to fast-fail if the user provided more "outputs" than
>> "max_outputs". I
>> > can
>> > perform the validation in virtio_gpu_base_get_features but that seems
>> late.
>>
>> I'd suggest putting it in virtio_gpu_base_device_realize, as we already
>> have code there to validate 'max_outputs" is within limits.
>>
>>
>> With regards,
>> Daniel
>> --
>> |: https://berrange.com -o-
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>> |: https://libvirt.org -o-
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>>
>>
