Re: [Qemu-devel] [v3][PATCH 2/2] libxl: introduce gfx_passthru_kind

[Ian Campbell <ian.campbell@citrix.com>]

On Mon, 2015-03-30 at 09:28 +0800, Chen, Tiejun wrote:
> Sounds it should be a legacy fix to qemu-xen-tranditional :) So lets do 
> it now,
> 
> @@ -326,6 +326,10 @@ static char ** 
> libxl__build_device_model_args_old(libxl__gc *gc,
>           }
>           if (libxl_defbool_val(b_info->u.hvm.gfx_passthru)) {
>               flexarray_append(dm_args, "-gfx_passthru");
> +            if (b_info->u.hvm.gfx_passthru_kind >
> +                                            LIBXL_GFX_PASSTHRU_KIND_IGD)
> +                LOG(ERROR, "unsupported device type for 
> \"gfx_passthru\".\n");
> +                return NULL;

I'd rather not encode any ordering constraints if we don't have to. I
think this is preferable:

          if (libxl_defbool_val(b_info->u.hvm.gfx_passthru)) {
               switch (b_info->u.hvm.gfx_passthru_kind) {
               case LIBXL_GFX_PASSTHRU_KIND_DEFAULT:
               case LIBXL_GFX_PASSTHRU_KIND_IGD:
                   flexarray_append(dm_args, "-gfx_passthru");
                   break;
               default:
                   LOG(ERROR, "unsupported gfx_passthru_kind.\n");
                   return NULL;
               }
         }

(notice that the error message above doesn't refer to the xl specific
option naming).

Ian.