Re: How to create and start Xen guest VM by qemu-system-x86_64 command line

[Trigger Huang <trigger.huang@xxxxxxxxx>]

Hi Jason,

Thanks for sharing.

Yesterday I added some hard code in libxl__build_device_model_args_new() and it worked. :)

I think your method is much more flexible, I will have a try at it.

Regards,

Trigger

My draft patch:

diff --git a/tools/libs/light/libxl_dm.c b/tools/libs/light/libxl_dm.c
index 9a8ddbe188..74961d0218 100644
--- a/tools/libs/light/libxl_dm.c
+++ b/tools/libs/light/libxl_dm.c
@@ -1346,7 +1346,7 @@ static int libxl__build_device_model_args_new(libxl__gc *gc,
      * Ensure that by default no display backend is created. Further
      * options given below might then enable more.
      */
-    flexarray_append_pair(dm_args, "-display", "none");
+   flexarray_append_pair(dm_args, "-display", "sdl,gl=on");

     if (sdl && !is_stubdom) {
         flexarray_append(dm_args, "-sdl");
@@ -1449,9 +1449,9 @@ static int libxl__build_device_model_args_new(libxl__gc *gc,
                 libxl__sizekb_to_mb(b_info->video_memkb)));
             break;
         case LIBXL_VGA_INTERFACE_TYPE_CIRRUS:
-            flexarray_append_pair(dm_args, "-device",
-                GCSPRINTF("cirrus-vga,vgamem_mb=%d",
-                libxl__sizekb_to_mb(b_info->video_memkb)));
+               flexarray_append_pair(dm_args, "-device", "virtio-vga-gl");
+               flexarray_append_pair(dm_args, "-vga", "none");
+               printf("Delete cirrus-vga, and add sdl display and virtio-vga-gl!\n");
             break;
         case LIBXL_VGA_INTERFACE_TYPE_NONE:
             break;

On Tue, Mar 8, 2022 at 10:19 AM Jason Andryuk <jandryuk@xxxxxxxxx> wrote:

On Sun, Mar 6, 2022 at 7:47 PM Trigger Huang <trigger.huang@xxxxxxxxx> wrote:
>
> Hi Alex,
>
> Thanks for the response.
>
> Actually my target is trying to enable virglrenderer on Xen based Qemu. Before, I have successfully enabled it on KVM based Qemu by the Qemu command line. Such as 'qemu-system-x86_64 -device virtio-vga-gl  xxxxxxx'
> If change to use xl, I don't know how to set this kind of special option(-device virtio-vga-gl ) to qemu after I checked the xl's arguments. Or do you have any idea? :)

You can use device_model_args in your xl.cfg:

       device_model_args=[ "ARG", "ARG", ...]
           Pass additional arbitrary options on the device-model command line.
           Each element in the list is passed as an option to the device-
           model.

Regards,
Jason