Re: [PATCH v3 64/75] x86/sev-es: Cache CPUID results for improved performance

[Joerg Roedel]

On Tue, Apr 28, 2020 at 05:17:14PM +0200, Joerg Roedel wrote:
> From: Mike Stunes <mstunes@xxxxxxxxxx>
> 
> To avoid a future VMEXIT for a subsequent CPUID function, cache the
> results returned by CPUID into an xarray.
> 
>  [tl: coding standard changes, register zero extension]
> 
> Signed-off-by: Mike Stunes <mstunes@xxxxxxxxxx>
> Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
> [ jroedel@xxxxxxx: - Wrapped cache handling into vc_handle_cpuid_cached()
>                    - Used lower_32_bits() where applicable
> 		   - Moved cache_index out of struct es_em_ctxt ]
> Co-developed-by: Joerg Roedel <jroedel@xxxxxxx>
> Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
> ---
>  arch/x86/kernel/sev-es-shared.c |  12 ++--
>  arch/x86/kernel/sev-es.c        | 119 +++++++++++++++++++++++++++++++-
>  2 files changed, 124 insertions(+), 7 deletions(-)

Okay, following the discussion, I am dropping this patch for now. We can
revisit CPUID caching later when we have a better justification.

Regards,

	Joerg