The following commit has been merged into the x86/cpu branch of tip:
Commit-ID: eea6c7957ae7fa2bf90e44c91ef013176db69483
Gitweb: https://git.kernel.org/tip/eea6c7957ae7fa2bf90e44c91ef013176db69483
Author: Kim Phillips <kim.phillips@xxxxxxx>
AuthorDate: Mon, 16 Jan 2023 17:01:59 -06:00
Committer: Borislav Petkov (AMD) <bp@xxxxxxxxx>
CommitterDate: Tue, 17 Jan 2023 13:00:12 +01:00
x86/cpu, kvm: Propagate the AMD Automatic IBRS feature to the guest
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@xxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Link: https://lore.kernel.org/r/20230116230159.1511393-8-kim.phillips@xxxxxxx
---
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 56f00d9..6ce0203 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 9a194aa..60c7c88 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 da4bbd0..8dd0cb2 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;
|