Re: [PATCH v3 06/28] drm/i915/gvt: Error out on an attempt to shadowing an unknown GTT entry type

[Wang, Zhi A]

On 5/13/2023 8:35 AM, Sean Christopherson wrote:

Reviewed-by: Zhi Wang <zhi.a.wang@xxxxxxxxx>

> Bail from ppgtt_populate_shadow_entry() if an unexpected GTT entry type
> is encountered instead of subtly falling through to the common "direct
> shadow" path.  Eliminating the default/error path's reliance on the common
> handling will allow hoisting intel_gvt_dma_map_guest_page() into the case
> statements so that the 2MiB case can try intel_gvt_dma_map_guest_page()
> and fallback to splitting the entry on failure.
> 
> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> ---
>   drivers/gpu/drm/i915/gvt/gtt.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
> index 2aed31b497c9..61e38acee2d5 100644
> --- a/drivers/gpu/drm/i915/gvt/gtt.c
> +++ b/drivers/gpu/drm/i915/gvt/gtt.c
> @@ -1306,6 +1306,7 @@ static int ppgtt_populate_shadow_entry(struct intel_vgpu *vgpu,
>   		return -EINVAL;
>   	default:
>   		GEM_BUG_ON(1);
> +		return -EINVAL;
>   	}
>   
>   	/* direct shadow */