Messages in this thread Patch in this message | | | From | Tom Lendacky <> | Subject | [PATCH v3 14/14] x86/sev: Allow non-VMPL0 execution when an SVSM is present | Date | Mon, 25 Mar 2024 17:26:33 -0500 |
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To allow execution at a level other than VMPL0, an SVSM must be present. Allow the SEV-SNP guest to continue booting if an SVSM is detected and the hypervisor supports the SVSM feature as indicated in the GHCB hypervisor features bitmap.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> --- arch/x86/boot/compressed/sev.c | 11 +++++++++-- arch/x86/include/asm/sev-common.h | 1 + arch/x86/kernel/sev.c | 20 +++++++++++++++++--- 3 files changed, 27 insertions(+), 5 deletions(-)
diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c index f8407ee83ac8..974201ba2499 100644 --- a/arch/x86/boot/compressed/sev.c +++ b/arch/x86/boot/compressed/sev.c @@ -619,10 +619,17 @@ void sev_enable(struct boot_params *bp) * features. */ if (sev_status & MSR_AMD64_SEV_SNP_ENABLED) { - if (!(get_hv_features() & GHCB_HV_FT_SNP)) + u64 hv_features = get_hv_features(); + + if (!(hv_features & GHCB_HV_FT_SNP)) sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED); - if (!running_at_vmpl0(&boot_ghcb_page)) + /* + * VMPL0 is not required if an SVSM is present and the hypervisor + * supports the required SVSM GHCB events. + */ + if (!running_at_vmpl0(&boot_ghcb_page) && + !(vmpl && (hv_features & GHCB_HV_FT_SNP_MULTI_VMPL))) sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_NOT_VMPL0); } diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h index 71db5ba020b9..3de377a4e981 100644 --- a/arch/x86/include/asm/sev-common.h +++ b/arch/x86/include/asm/sev-common.h @@ -118,6 +118,7 @@ enum psc_op { #define GHCB_HV_FT_SNP BIT_ULL(0) #define GHCB_HV_FT_SNP_AP_CREATION BIT_ULL(1) +#define GHCB_HV_FT_SNP_MULTI_VMPL BIT_ULL(5) /* * SNP Page State Change NAE event diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 0a06632898c6..fd3a832c65ec 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -2366,22 +2366,36 @@ static void dump_cpuid_table(void) * sort of indicator, and there's not really any other good place to do it, * so do it here. */ -static int __init report_cpuid_table(void) +static void __init report_cpuid_table(void) { const struct snp_cpuid_table *cpuid_table = snp_cpuid_get_table(); if (!cpuid_table->count) - return 0; + return; pr_info("Using SNP CPUID table, %d entries present.\n", cpuid_table->count); if (sev_cfg.debug) dump_cpuid_table(); +} + +static void __init report_vmpl_level(void) +{ + if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) + return; + + pr_info("SNP running at VMPL%u.\n", vmpl); +} + +static int __init report_snp_info(void) +{ + report_vmpl_level(); + report_cpuid_table(); return 0; } -arch_initcall(report_cpuid_table); +arch_initcall(report_snp_info); static int __init init_sev_config(char *str) { -- 2.43.2
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