Re: [PATCH Part1 RFC v4 22/36] x86/sev: move MSR-based VMGEXITs for CPUID to helper
From: Borislav Petkov <bp@alien8.de>
Date: 2021-08-19 16:46:28
Also in:
kvm, linux-coco, linux-crypto, lkml, platform-driver-x86
On Thu, Aug 19, 2021 at 10:37:41AM -0500, Michael Roth wrote:
That makes sense, but I think it helps in making sense of the security aspects of the code to know that sev_cpuid() would be fetching cpuid information from the hypervisor.
Why is it important for the callers to know where do we fetch the CPUID info from?
"msr_proto" is meant to be an indicator that it will be using the GHCB MSR protocol to do it, but maybe just "_hyp" is enough to get the idea across? I use the convention elsewhere in the series as well. So sev_cpuid_hyp() maybe?
sev_cpuid_hv() pls. We abbreviate the hypervisor as HV usually.
In "enable SEV-SNP-validated CPUID in #VC handler", it does:
sev_snp_cpuid() -> sev_snp_cpuid_hyp(),
which will call this with NULL e{a,b,c,d}x arguments in some cases. There
are enough call-sites in sev_snp_cpuid() that it seemed worthwhile to
add the guards so we wouldn't need to declare dummy variables for arguments.
Yah, saw that in the later patches.
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette