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Diffstat (limited to 'arch/x86/boot/compressed/sev.c')
-rw-r--r--arch/x86/boot/compressed/sev.c70
1 files changed, 70 insertions, 0 deletions
diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index c93930d5ccbd..d63ad8f99f83 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -208,6 +208,23 @@ void sev_es_shutdown_ghcb(void)
error("Can't unmap GHCB page");
}
+static void __noreturn sev_es_ghcb_terminate(struct ghcb *ghcb, unsigned int set,
+ unsigned int reason, u64 exit_info_2)
+{
+ u64 exit_info_1 = SVM_VMGEXIT_TERM_REASON(set, reason);
+
+ vc_ghcb_invalidate(ghcb);
+ ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_TERM_REQUEST);
+ ghcb_set_sw_exit_info_1(ghcb, exit_info_1);
+ ghcb_set_sw_exit_info_2(ghcb, exit_info_2);
+
+ sev_es_wr_ghcb_msr(__pa(ghcb));
+ VMGEXIT();
+
+ while (true)
+ asm volatile("hlt\n" : : : "memory");
+}
+
bool sev_es_check_ghcb_fault(unsigned long address)
{
/* Check whether the fault was on the GHCB page */
@@ -270,6 +287,59 @@ static void enforce_vmpl0(void)
sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_NOT_VMPL0);
}
+/*
+ * SNP_FEATURES_IMPL_REQ is the mask of SNP features that will need
+ * guest side implementation for proper functioning of the guest. If any
+ * of these features are enabled in the hypervisor but are lacking guest
+ * side implementation, the behavior of the guest will be undefined. The
+ * guest could fail in non-obvious way making it difficult to debug.
+ *
+ * As the behavior of reserved feature bits is unknown to be on the
+ * safe side add them to the required features mask.
+ */
+#define SNP_FEATURES_IMPL_REQ (MSR_AMD64_SNP_VTOM | \
+ MSR_AMD64_SNP_REFLECT_VC | \
+ MSR_AMD64_SNP_RESTRICTED_INJ | \
+ MSR_AMD64_SNP_ALT_INJ | \
+ MSR_AMD64_SNP_DEBUG_SWAP | \
+ MSR_AMD64_SNP_VMPL_SSS | \
+ MSR_AMD64_SNP_SECURE_TSC | \
+ MSR_AMD64_SNP_VMGEXIT_PARAM | \
+ MSR_AMD64_SNP_VMSA_REG_PROTECTION | \
+ MSR_AMD64_SNP_RESERVED_BIT13 | \
+ MSR_AMD64_SNP_RESERVED_BIT15 | \
+ MSR_AMD64_SNP_RESERVED_MASK)
+
+/*
+ * SNP_FEATURES_PRESENT is the mask of SNP features that are implemented
+ * by the guest kernel. As and when a new feature is implemented in the
+ * guest kernel, a corresponding bit should be added to the mask.
+ */
+#define SNP_FEATURES_PRESENT (0)
+
+void snp_check_features(void)
+{
+ u64 unsupported;
+
+ if (!(sev_status & MSR_AMD64_SEV_SNP_ENABLED))
+ return;
+
+ /*
+ * Terminate the boot if hypervisor has enabled any feature lacking
+ * guest side implementation. Pass on the unsupported features mask through
+ * EXIT_INFO_2 of the GHCB protocol so that those features can be reported
+ * as part of the guest boot failure.
+ */
+ unsupported = sev_status & SNP_FEATURES_IMPL_REQ & ~SNP_FEATURES_PRESENT;
+ if (unsupported) {
+ if (ghcb_version < 2 || (!boot_ghcb && !early_setup_ghcb()))
+ sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
+
+ sev_es_ghcb_terminate(boot_ghcb, SEV_TERM_SET_GEN,
+ GHCB_SNP_UNSUPPORTED, unsupported);
+ }
+}
+
void sev_enable(struct boot_params *bp)
{
unsigned int eax, ebx, ecx, edx;