diff options
| -rw-r--r-- | arch/x86/boot/startup/sev-shared.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/x86/boot/startup/sev-shared.c b/arch/x86/boot/startup/sev-shared.c index 08cc1568d8af..4e22ffd73516 100644 --- a/arch/x86/boot/startup/sev-shared.c +++ b/arch/x86/boot/startup/sev-shared.c @@ -458,6 +458,13 @@ void do_vc_no_ghcb(struct pt_regs *regs, unsigned long exit_code) leaf.fn = fn; leaf.subfn = subfn; + /* + * If SNP is active, then snp_cpuid() uses the CPUID table to obtain the + * CPUID values (with possible HV interaction during post-processing of + * the values). But if SNP is not active (no CPUID table present), then + * snp_cpuid() returns -EOPNOTSUPP so that an SEV-ES guest can call the + * HV to obtain the CPUID information. + */ ret = snp_cpuid(snp_cpuid_hv_msr, NULL, &leaf); if (!ret) goto cpuid_done; @@ -465,6 +472,10 @@ void do_vc_no_ghcb(struct pt_regs *regs, unsigned long exit_code) if (ret != -EOPNOTSUPP) goto fail; + /* + * This is reached by a SEV-ES guest and needs to invoke the HV for + * the CPUID data. + */ if (__sev_cpuid_hv_msr(&leaf)) goto fail; |