Re: [PATCH v2 09/13] x86/emulator: Refactor FXSAVE_AREA to use wrappers

[Jan Beulich]

On 16.12.2024 12:58, Alejandro Vallejo wrote:
> On Mon Dec 9, 2024 at 4:26 PM GMT, Jan Beulich wrote:
>> On 05.11.2024 15:33, Alejandro Vallejo wrote:
>>> --- 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(currt ent, x)
>>
>> The typo of the first argument strongly suggests that the macro should
>> already now evaluate its parameters, also pleasing Misra.
> 
> Not an unreasonable takeaway. I can expand as follows instead:
> 
> #define VCPU_UNMAP_XSAVE_AREA(v, x) ({ (void)(v); x; })
> 
> Thoughts?

Why would x not also be cast to void?

Jan