Re: [PATCH for-4.19] gnttab: fix compat query-size handling

[Oleksii <oleksii.kurochko@xxxxxxxxx>]

On Tue, 2024-06-25 at 09:30 +0200, Jan Beulich wrote:
> The odd DEFINE_XEN_GUEST_HANDLE(), inconsistent with all other
> similar
> constructs, should have caught my attention. Turns out it was needed
> for
> the build to succeed merely because the corresponding #ifndef had a
> typo. That typo in turn broke compat mode guests, by having query-
> size
> requests of theirs wire into the domain_crash() at the bottom of the
> switch().
> 
> Fixes: 8c3bb4d8ce3f ("xen/gnttab: Perform compat/native
> gnttab_query_size check")
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Release-Acked-by: Oleksii Kurochko <Oleksii.kurochko@xxxxxxxxx>

~ Oleksii

> ---
> Looks like set-version is similarly missing in the set of structures
> checked, but I'm pretty sure that we will now want to defer taking
> care
> of that until after 4.20 was branched.
> 
> --- a/xen/common/compat/grant_table.c
> +++ b/xen/common/compat/grant_table.c
> @@ -33,7 +33,6 @@ CHECK_gnttab_unmap_and_replace;
>  #define xen_gnttab_query_size gnttab_query_size
>  CHECK_gnttab_query_size;
>  #undef xen_gnttab_query_size
> -DEFINE_XEN_GUEST_HANDLE(gnttab_query_size_compat_t);
>  
>  DEFINE_XEN_GUEST_HANDLE(gnttab_setup_table_compat_t);
>  DEFINE_XEN_GUEST_HANDLE(gnttab_transfer_compat_t);
> @@ -111,7 +110,7 @@ int compat_grant_table_op(
>      CASE(copy);
>  #endif
>  
> -#ifndef CHECK_query_size
> +#ifndef CHECK_gnttab_query_size
>      CASE(query_size);
>  #endif
>