x86/bugs: Add AMD's SPEC_CTRL MSR usage

[linux-2.6-block.git] / arch / x86 / kvm / cpuid.c

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 92bf2f2e7cdd241d1b4019c0ed72ce72fbb95d11..f4f30d0c25c426388fb962fdcd04e76b508755cc 100644 (file)
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -379,7 +379,8 @@ 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(VIRT_SSBD);
+               F(AMD_IBPB) | F(AMD_IBRS) | F(AMD_SSBD) | F(VIRT_SSBD) |
+               F(AMD_SSB_NO);
 
        /* cpuid 0xC0000001.edx */
        const u32 kvm_cpuid_C000_0001_edx_x86_features =
@@ -664,7 +665,12 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
                        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))
+               /*
+                * The preference is to use SPEC CTRL MSR instead of the
+                * VIRT_SPEC MSR.
+                */
+               if (boot_cpu_has(X86_FEATURE_LS_CFG_SSBD) &&
+                   !boot_cpu_has(X86_FEATURE_AMD_SSBD))
                        entry->ebx |= F(VIRT_SSBD);
                break;
        }