Re: [Qemu-devel] [RFC][PATCH 1/1] libxl: add one machine property to support IGD GFX passthrough

["Chen, Tiejun" <tiejun.chen@intel.com>]

On 2015/1/28 19:12, Wei Liu wrote:
> On Wed, Jan 28, 2015 at 08:42:56AM +0800, Chen, Tiejun wrote:
>> On 2015/1/27 22:40, Ian Jackson wrote:
>>> Chen, Tiejun writes ("Re: [Qemu-devel] [RFC][PATCH 1/1] libxl: add one machine property to support IGD GFX passthrough"):
>>>> On 2015/1/23 8:43, Chen, Tiejun wrote:
>>>>> On 2015/1/22 8:51, Chen, Tiejun wrote:
>>>>>> At this point I just concern here if we still use 'gfx_passthrou', at
>>>>>> least it may look like a backward compatibility with older versions of
>>>>>> qemu in Xen side, qemu-xen-traditional. But I'd like to follow your
>>>>>> final option.
>>> ...
>>>>> Any feedback to this option I should follow here?
>>>>
>>>> Ping...
>>>
>>> I think this is a question that qemu upstream should answer.
>>>
>>
>> Actually this is just commented by Gerd in qemu upstream. So now looks in
>> Xen side you guys don't have any objection to use 'igd-passthru' as well. If
>> yes, I'm fine to adopt this.
>>
>
> Yes, we would like to stay in line with upstream.

Wei,

Thanks for your response.

>
> Just remember to handle old option in libxl if your old option is already
> released by some older version of QEMUs.

I just drop that old option, -gfx_passthru, if we're under qemu upstream 
circumstance, like this,

--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -318,7 +318,10 @@ static char ** 
libxl__build_device_model_args_old(libxl__gc *gc,
              flexarray_vappend(dm_args, "-net", "none", NULL);
          }
          if (libxl_defbool_val(b_info->u.hvm.gfx_passthru)) {
-            flexarray_append(dm_args, "-gfx_passthru");
+            if (b_info->device_model_version !=
+                LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN) {
+                flexarray_append(dm_args, "-gfx_passthru");
+            }
          }
      } else {
          if (!sdl && !vnc)
@@ -702,7 +705,10 @@ static char ** 
libxl__build_device_model_args_new(libxl__gc *gc,
              flexarray_append(dm_args, "none");
          }
          if (libxl_defbool_val(b_info->u.hvm.gfx_passthru)) {
-            flexarray_append(dm_args, "-gfx_passthru");
+            if (b_info->device_model_version !=
+                LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN) {
+                flexarray_append(dm_args, "-gfx_passthru");
+            }
          }
      } else {
          if (!sdl && !vnc) {

Is this good enough?

Thanks
Tiejun