[PATCH v3 7/7] x86/cpu, kvm: Propagate the AMD Automatic IBRS feature to the guest

Kim Phillips
2022-11-30T00:00:45Z

Add the AMD Automatic IBRS feature bit to those being
propagated to the guest.

Signed-off-by: Kim Phillips <kim.phillips@amd.com>
---
arch/x86/kvm/cpuid.c | 2 +-
arch/x86/kvm/reverse_cpuid.h | 2 ++
2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 8e37760cea1b..acda3883a905 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -743,7 +743,7 @@ void kvm_set_cpu_caps(void)
*/
kvm_cpu_cap_init_scattered(CPUID_8000_0021_EAX,
SF(NO_NESTED_DATA_BP) | SF(LFENCE_RDTSC) |
- SF(NULL_SEL_CLR_BASE));
+ SF(NULL_SEL_CLR_BASE) | SF(AUTOIBRS));
if (cpu_feature_enabled(X86_FEATURE_LFENCE_RDTSC))
kvm_cpu_cap_set(X86_FEATURE_LFENCE_RDTSC);
if (!static_cpu_has_bug(X86_BUG_NULL_SEG))
diff --git a/arch/x86/kvm/reverse_cpuid.h b/arch/x86/kvm/reverse_cpuid.h
index 184614e27d5b..0bf02c02bb0a 100644
--- a/arch/x86/kvm/reverse_cpuid.h
+++ b/arch/x86/kvm/reverse_cpuid.h
@@ -30,6 +30,7 @@ enum kvm_only_cpuid_leafs {
#define KVM_X86_FEATURE_NO_NESTED_DATA_BP KVM_X86_FEATURE(CPUID_8000_0021_EAX, 0)
#define KVM_X86_FEATURE_LFENCE_RDTSC KVM_X86_FEATURE(CPUID_8000_0021_EAX, 2)
#define KVM_X86_FEATURE_NULL_SEL_CLR_BASE KVM_X86_FEATURE(CPUID_8000_0021_EAX, 6)
+#define KVM_X86_FEATURE_AUTOIBRS KVM_X86_FEATURE(CPUID_8000_0021_EAX, 8)

struct cpuid_reg {
u32 function;
@@ -89,6 +90,7 @@ static __always_inline u32 __feature_translate(int x86_feature)
case X86_FEATURE_NO_NESTED_DATA_BP: return KVM_X86_FEATURE_NO_NESTED_DATA_BP;
case X86_FEATURE_LFENCE_RDTSC: return KVM_X86_FEATURE_LFENCE_RDTSC;
case X86_FEATURE_NULL_SEL_CLR_BASE: return KVM_X86_FEATURE_NULL_SEL_CLR_BASE;
+ case X86_FEATURE_AUTOIBRS: return KVM_X86_FEATURE_AUTOIBRS;
default: break;
}

--
2.34.1