summaryrefslogtreecommitdiff
path: root/arch
diff options
context:
space:
mode:
authorJim Mattson <jmattson@google.com>2019-12-13 16:15:16 -0800
committerPaolo Bonzini <pbonzini@redhat.com>2019-12-18 17:46:35 +0100
commit8715f05269bfbc6453e25e80825d781a82902f8e (patch)
tree633859ce341be90e9340947b7c13f1386b802267 /arch
parent396d2e878f92ec108e4293f1c77ea3bc90b414ff (diff)
kvm: x86: Host feature SSBD doesn't imply guest feature AMD_SSBD
The host reports support for the synthetic feature X86_FEATURE_SSBD when any of the three following hardware features are set: CPUID.(EAX=7,ECX=0):EDX.SSBD[bit 31] CPUID.80000008H:EBX.AMD_SSBD[bit 24] CPUID.80000008H:EBX.VIRT_SSBD[bit 25] Either of the first two hardware features implies the existence of the IA32_SPEC_CTRL MSR, but CPUID.80000008H:EBX.VIRT_SSBD[bit 25] does not. Therefore, CPUID.80000008H:EBX.AMD_SSBD[bit 24] should only be set in the guest if CPUID.(EAX=7,ECX=0):EDX.SSBD[bit 31] or CPUID.80000008H:EBX.AMD_SSBD[bit 24] is set on the host. Fixes: 4c6903a0f9d76 ("KVM: x86: fix reporting of AMD speculation bug CPUID leaf") Signed-off-by: Jim Mattson <jmattson@google.com> Reviewed-by: Jacob Xu <jacobhxu@google.com> Reviewed-by: Peter Shier <pshier@google.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: stable@vger.kernel.org Reported-by: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/cpuid.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index dd18aa6fa317..bf715e5fd35c 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -760,7 +760,8 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
entry->ebx |= F(AMD_IBRS);
if (boot_cpu_has(X86_FEATURE_STIBP))
entry->ebx |= F(AMD_STIBP);
- if (boot_cpu_has(X86_FEATURE_SSBD))
+ if (boot_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD) ||
+ boot_cpu_has(X86_FEATURE_AMD_SSBD))
entry->ebx |= F(AMD_SSBD);
if (!boot_cpu_has_bug(X86_BUG_SPEC_STORE_BYPASS))
entry->ebx |= F(AMD_SSB_NO);