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Subject[PATCH v7 7/7] x86/cpu, kvm: Propagate the AMD Automatic IBRS feature to the guest
Date
Add the AMD Automatic IBRS feature bit to those being
propagated to the guest, and enable the guest EFER bit.

Signed-off-by: Kim Phillips <kim.phillips@amd.com>
---
arch/x86/kvm/cpuid.c | 2 +-
arch/x86/kvm/svm/svm.c | 3 +++
arch/x86/kvm/x86.c | 3 +++
3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 9ba75ad9d976..293ef07b34c3 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_mask(CPUID_8000_0021_EAX,
F(NO_NESTED_DATA_BP) | F(LFENCE_RDTSC) | 0 /* SmmPgCfgLock */ |
- F(NULL_SEL_CLR_BASE) | 0 /* PrefetchCtlMsr */
+ F(NULL_SEL_CLR_BASE) | F(AUTOIBRS) | 0 /* PrefetchCtlMsr */
);
if (cpu_feature_enabled(X86_FEATURE_LFENCE_RDTSC))
kvm_cpu_cap_set(X86_FEATURE_LFENCE_RDTSC);
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 9a194aa1a75a..60c7c880266b 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4969,6 +4969,9 @@ static __init int svm_hardware_setup(void)

tsc_aux_uret_slot = kvm_add_user_return_msr(MSR_TSC_AUX);

+ if (boot_cpu_has(X86_FEATURE_AUTOIBRS))
+ kvm_enable_efer_bits(EFER_AUTOIBRS);
+
/* Check for pause filtering support */
if (!boot_cpu_has(X86_FEATURE_PAUSEFILTER)) {
pause_filter_count = 0;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index da4bbd043a7b..8dd0cb230ef5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1685,6 +1685,9 @@ static int do_get_msr_feature(struct kvm_vcpu *vcpu, unsigned index, u64 *data)

static bool __kvm_valid_efer(struct kvm_vcpu *vcpu, u64 efer)
{
+ if (efer & EFER_AUTOIBRS && !guest_cpuid_has(vcpu, X86_FEATURE_AUTOIBRS))
+ return false;
+
if (efer & EFER_FFXSR && !guest_cpuid_has(vcpu, X86_FEATURE_FXSR_OPT))
return false;

--
2.34.1
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