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 <[email protected]>
---
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