Re: [PATCH Part1 RFC v4 22/36] x86/sev: move MSR-based VMGEXITs for CPUID to helper

Borislav Petkov
2021-08-19T09:45:04Z

Finally drop this bouncing npmccallum at RH email address from the Cc
list.

On Wed, Jul 07, 2021 at 01:14:52PM -0500, Brijesh Singh wrote:
> From: Michael Roth <michael.roth@amd.com>
>
> This code will also be used later for SEV-SNP-validated CPUID code in
> some cases, so move it to a common helper.
>
> Signed-off-by: Michael Roth <michael.roth@amd.com>
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> ---
> arch/x86/kernel/sev-shared.c | 84 +++++++++++++++++++++++++-----------
> 1 file changed, 58 insertions(+), 26 deletions(-)
>
> diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
> index be4025f14b4f..4884de256a49 100644
> --- a/arch/x86/kernel/sev-shared.c
> +++ b/arch/x86/kernel/sev-shared.c
> @@ -184,6 +184,58 @@ static enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb,
> return ret;
> }
>
> +static int sev_es_cpuid_msr_proto(u32 func, u32 subfunc, u32 *eax, u32 *ebx,

Since it is not only SEV-ES, then it should be prefixed with "sev_" like
we do for the other such functions. I guess simply

sev_cpuid()

?

> + u32 *ecx, u32 *edx)
> +{
> + u64 val;
> +
> + if (eax) {

What's the protection for? Is it ever going to be called with NULL ptrs
for the regs? That's not the case in this patchset at least...

--
Regards/Gruss,
Boris.