KVM: SVM: Implement VIRT_SPEC_CTRL support for SSBD
Expose the new virtualized architectural mechanism, VIRT_SSBD, for using
speculative store bypass disable (SSBD) under SVM. This will allow guests
to use SSBD on hardware that uses non-architectural mechanisms for enabling
SSBD.
[ tglx: Folded the migration fixup from Paolo Bonzini ]
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index e5ba485..ced8511 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -379,7 +379,7 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
/* cpuid 0x80000008.ebx */
const u32 kvm_cpuid_8000_0008_ebx_x86_features =
- F(AMD_IBPB) | F(AMD_IBRS);
+ F(AMD_IBPB) | F(AMD_IBRS) | F(VIRT_SSBD);
/* cpuid 0xC0000001.edx */
const u32 kvm_cpuid_C000_0001_edx_x86_features =
@@ -647,13 +647,20 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
g_phys_as = phys_as;
entry->eax = g_phys_as | (virt_as << 8);
entry->edx = 0;
- /* IBRS and IBPB aren't necessarily present in hardware cpuid */
+ /*
+ * IBRS, IBPB and VIRT_SSBD aren't necessarily present in
+ * hardware cpuid
+ */
if (boot_cpu_has(X86_FEATURE_AMD_IBPB))
entry->ebx |= F(AMD_IBPB);
if (boot_cpu_has(X86_FEATURE_AMD_IBRS))
entry->ebx |= F(AMD_IBRS);
+ if (boot_cpu_has(X86_FEATURE_VIRT_SSBD))
+ entry->ebx |= F(VIRT_SSBD);
entry->ebx &= kvm_cpuid_8000_0008_ebx_x86_features;
cpuid_mask(&entry->ebx, CPUID_8000_0008_EBX);
+ if (boot_cpu_has(X86_FEATURE_LS_CFG_SSBD))
+ entry->ebx |= F(VIRT_SSBD);
break;
}
case 0x80000019: