On 14/09/2023 9:51 am, Jan Beulich wrote:
> On 13.09.2023 22:27, Andrew Cooper wrote:
>> All other SPEC_CTRL_{ENTRY,EXIT}_* helpers hold stack_end in %r14. Adjust it
>> for consistency, freeing up %rbx to be used differently.
>>
>> Signed-off-by: Andrew Cooper <[email protected]>
> Reviewed-by: Jan Beulich <[email protected]>
>
> The choice of %rbx was, iirc, for avoiding unnecessary code size increase
> (due to extra REX prefixes needed in some of the affected insns). I
> understand you view this as not a real concern, but I think saying so
> explicitly in the description would be at least desirable. After all there
> would also be the alternative of further parametrizing the involved macros.
Yeah I'm seriously not concerned about a REX prefix or two.
This is about making all the helpers more consistent, to cut down on the
number of errors involved in modifying this mess.
~Andrew
