Re: [PATCH v3 08/12] x86/emulator: Refactor FXSAVE_AREA to use wrappers

[Jan Beulich]

On 10.01.2025 14:28, Alejandro Vallejo wrote:
> Adds an UNMAP primitive to make use of vcpu_unmap_xsave_area() when
> linked into xen. unmap is a no-op during tests.
> 
> Signed-off-by: Alejandro Vallejo <alejandro.vall...@cloud.com>

Acked-by: Jan Beulich <jbeul...@suse.com>
despite ...

> --- a/xen/arch/x86/x86_emulate/blk.c
> +++ b/xen/arch/x86/x86_emulate/blk.c
> @@ -11,9 +11,12 @@
>      !defined(X86EMUL_NO_SIMD)
>  # ifdef __XEN__
>  #  include <asm/xstate.h>
> -#  define FXSAVE_AREA ((void *)&current->arch.xsave_area->fpu_sse)
> +/* Has a fastpath for `current`, so there's no actual map */
> +#  define FXSAVE_AREA ((void *)VCPU_MAP_XSAVE_AREA(current))
> +#  define UNMAP_FXSAVE_AREA(x) VCPU_UNMAP_XSAVE_AREA(current, x)

... the comment here kind of suggesting that ...

>  # else
>  #  define FXSAVE_AREA get_fpu_save_area()
> +#  define UNMAP_FXSAVE_AREA(x) ((void)(x))

... use of this new construct is solely decoration, and could hence as
well be omitted.

Jan