Re: [PATCH 4/5] xen/memory: Fix acquire_resource size semantics

[Jan Beulich <jbeulich@xxxxxxxx>]

On 28.07.2020 13:37, Andrew Cooper wrote:
> @@ -1026,19 +1047,6 @@ static int acquire_resource(
>      if ( xmar.pad != 0 )
>          return -EINVAL;
>  
> -    if ( guest_handle_is_null(xmar.frame_list) )
> -    {
> -        if ( xmar.nr_frames )
> -            return -EINVAL;
> -
> -        xmar.nr_frames = ARRAY_SIZE(mfn_list);
> -
> -        if ( __copy_field_to_guest(arg, &xmar, nr_frames) )
> -            return -EFAULT;
> -
> -        return 0;
> -    }
> -
>      if ( xmar.nr_frames > ARRAY_SIZE(mfn_list) )
>          return -E2BIG;

While arguably minor, the error code in the null-handle case
would imo better be the same, no matter how big xmar.nr_frames
is.

Jan