[libvirt] [PATCH v2 4/5] qemu: Add QEMU_CAPS_SDL_GL to qemu capabilities

[John Ferlan]

On 05/11/2018 04:26 AM, Martin Kletzander wrote:
> On Thu, May 10, 2018 at 04:17:52PM -0400, John Ferlan wrote:
>>
>>
>> On 05/10/2018 06:53 AM, Maciej Wolny wrote:
>>> Support OpenGL acceleration capability when using SDL graphics.
>>>
>>> Signed-off-by: Maciej Wolny <maciej.wolny at codethink.co.uk>
>>> ---
>>>  src/qemu/qemu_capabilities.c                         | 2 ++
>>>  src/qemu/qemu_capabilities.h                         | 1 +
>>>  tests/qemucapabilitiesdata/caps_2.4.0.x86_64.replies | 9 +++++++++
>>>  tests/qemucapabilitiesdata/caps_2.4.0.x86_64.xml     | 3 ++-
>>>  4 files changed, 14 insertions(+), 1 deletion(-)
>>>
>>
>> As I rather lengthily noted in the v1 - I'm assuming you handed
>> edited the .replies file.  What that perhaps works and gets you
>> the answer, the fact that none of other files were adjusted leads
>> me to the hand editing belief.
>>
>>> diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
>>> index 920a59617..23f917b66 100644
>>> --- a/src/qemu/qemu_capabilities.c
>>> +++ b/src/qemu/qemu_capabilities.c
>>> @@ -475,6 +475,7 @@ VIR_ENUM_IMPL(virQEMUCaps, QEMU_CAPS_LAST,
>>>                "disk-write-cache",
>>>                "nbd-tls",
>>>                "tpm-crb",
>>> +              "sdl-gl",
>>>      );
>>>
>>>
>>> @@ -2456,6 +2457,7 @@ static struct virQEMUCapsCommandLineProps
>>> virQEMUCapsCommandLine[] = {
>>>      { "vnc", "vnc", QEMU_CAPS_VNC_MULTI_SERVERS },
>>>      { "chardev", "reconnect", QEMU_CAPS_CHARDEV_RECONNECT },
>>>      { "sandbox", "elevateprivileges", QEMU_CAPS_SECCOMP_BLACKLIST },
>>> +    { "sdl", "gl", QEMU_CAPS_SDL_GL },
>>>  };
>>
>> Rather than this, I'll apply the following diff:
>>
>> diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
>> index 23f917b66e..28079fa7ab 100644
>> --- a/src/qemu/qemu_capabilities.c
>> +++ b/src/qemu/qemu_capabilities.c
>> @@ -2457,7 +2457,6 @@ static struct virQEMUCapsCommandLineProps
>> virQEMUCapsCommandLine[] = {
>>     { "vnc", "vnc", QEMU_CAPS_VNC_MULTI_SERVERS },
>>     { "chardev", "reconnect", QEMU_CAPS_CHARDEV_RECONNECT },
>>     { "sandbox", "elevateprivileges", QEMU_CAPS_SECCOMP_BLACKLIST },
>> -    { "sdl", "gl", QEMU_CAPS_SDL_GL },
>> };
>>
>> static int
>> @@ -3828,6 +3827,10 @@ virQEMUCapsInitQMPMonitor(virQEMUCapsPtr qemuCaps,
>>     if (qemuCaps->version >= 2004000)
>>         virQEMUCapsSet(qemuCaps, QEMU_CAPS_MACHINE_SMM_OPT);
>>
>> +    /* sdl -gl option is supported from v2.4.0 (qemu commit id
>> 0b71a5d5) */
>> +    if (qemuCaps->version >= 2004000)
>> +        virQEMUCapsSet(qemuCaps, QEMU_CAPS_SDL_GL);
>> +
>>     /* Since 2.4.50 ARM virt machine supports gic-version option */
>>     if (qemuCaps->version >= 2004050)
>>         virQEMUCapsSet(qemuCaps, QEMU_CAPS_MACH_VIRT_GIC_VERSION);
>>
>>
> 
> NO! Why? We only result to setting capabilities by version if there is
> no other
> way to do that.  If query-commandline-options (or whatever that name is)
> works
> for this capability, why would you even consider this change?
> 
> NACK to the diff you added.

Are you sure? Did you read my responses from v1:

https://www.redhat.com/archives/libvir-list/2018-May/msg00250.html
https://www.redhat.com/archives/libvir-list/2018-May/msg00671.html

I actually spent some time trying to figure out which magic incantation
of the virQEMUCaps* would work. I even tried various forms in
virQEMUCapsQMPSchemaQueries, but could not get the flag to be added from
qemu 2.4 and beyond.  Again, my "assumption" is that it was hand edited
into the 2.4 replies that was added here mainly because none of the
other available sdl * options were addressed - just the one that was wanted.

Looking at the QEMU source code - AFAICT the gl option is only "known"
or handled within parse_options of vl.c.  I found nothing in the .json
files where I'd usually find some mechanism that would allow
introspection for the "-sdl gl" option. There is something in
qapi/ui.json that has 'gl' that looks like it could be used in some new
command syntax, but that seems to imply QEMU 2.12 only.

Please enlighten me/us with code that will work before just pushing the
NACK button.

Tks,

John