Re: [PATCH v4 5/7] x86/sev: Register the guest with the SVSM APIC protocol

[Melody Wang]

Hi Ard,

On 10/14/26 2:43 AM, Ard Biesheuvel wrote:
> I'm struggling to follow the logic here: doesn't this attempt to locate
> the protocol on non-SEV/SNP systems as well?

Alternate Injection is only working for SEV-SNP guest.

> Wouldn't it be sufficient to do
>
> if (!snp_vmpl ||
>     !(sev_get_status() & MSR_AMD64_SNP_ALTERNATE_INJ))
>         return 0;
>
> and leave the early_is_sevsnp_guest() check alone?

The thing is, snp_vmpl hasn't been initialized here yet. We read here a 
0. So I need early_is_sevsnp_guest() to initialize it to U8_MAX so that 
I know that there's an SVSM present.

Then I can enable AltInj.

--
Thanks,
Melody