Track "virtual VMSAVE/VMLOAD exposed to L1" via a governed feature flag
instead of using a dedicated bit/flag in vcpu_svm.
Opportunistically add a comment explaining why KVM disallows virtual
VMLOAD/VMSAVE when the vCPU model is Intel.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/governed_features.h | 1 +
arch/x86/kvm/svm/nested.c | 2 +-
arch/x86/kvm/svm/svm.c | 10 +++++++---
arch/x86/kvm/svm/svm.h | 1 -
4 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kvm/governed_features.h b/arch/x86/kvm/governed_features.h
index 32c0469cf952..f01a95fd0071 100644
--- a/arch/x86/kvm/governed_features.h
+++ b/arch/x86/kvm/governed_features.h
@@ -10,6 +10,7 @@ KVM_GOVERNED_X86_FEATURE(XSAVES)
KVM_GOVERNED_X86_FEATURE(VMX)
KVM_GOVERNED_X86_FEATURE(NRIPS)
KVM_GOVERNED_X86_FEATURE(TSCRATEMSR)
+KVM_GOVERNED_X86_FEATURE(V_VMSAVE_VMLOAD)
#undef KVM_GOVERNED_X86_FEATURE
#undef KVM_GOVERNED_FEATURE
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index da65948064dc..24d47ebeb0e0 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -107,7 +107,7 @@ static void nested_svm_uninit_mmu_context(struct kvm_vcpu *vcpu)
static bool nested_vmcb_needs_vls_intercept(struct vcpu_svm *svm)
{
- if (!svm->v_vmload_vmsave_enabled)
+ if (!guest_can_use(&svm->vcpu, X86_FEATURE_V_VMSAVE_VMLOAD))
return true;
if (!nested_npt_enabled(svm))
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 2f7f7df5a591..39a69c1786ea 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1154,8 +1154,6 @@ static inline void init_vmcb_after_set_cpuid(struct kvm_vcpu *vcpu)
set_msr_interception(vcpu, svm->msrpm, MSR_IA32_SYSENTER_EIP, 0, 0);
set_msr_interception(vcpu, svm->msrpm, MSR_IA32_SYSENTER_ESP, 0, 0);
-
- svm->v_vmload_vmsave_enabled = false;
} else {
/*
* If hardware supports Virtual VMLOAD VMSAVE then enable it
@@ -4226,7 +4224,13 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
svm->lbrv_enabled = lbrv && guest_cpuid_has(vcpu, X86_FEATURE_LBRV);
- svm->v_vmload_vmsave_enabled = vls && guest_cpuid_has(vcpu, X86_FEATURE_V_VMSAVE_VMLOAD);
+ /*
+ * Intercept VMLOAD if the vCPU mode is Intel in order to emulate that
+ * VMLOAD drops bits 63:32 of SYSENTER (ignoring the fact that exposing
+ * SVM on Intel is bonkers and extremely unlikely to work).
+ */
+ if (!guest_cpuid_is_intel(vcpu))
+ kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_V_VMSAVE_VMLOAD);
svm->pause_filter_enabled = kvm_cpu_cap_has(X86_FEATURE_PAUSEFILTER) &&
guest_cpuid_has(vcpu, X86_FEATURE_PAUSEFILTER);
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 4e7332f77702..b475241df6dc 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -259,7 +259,6 @@ struct vcpu_svm {
bool soft_int_injected;
/* optional nested SVM features that are enabled for this guest */
- bool v_vmload_vmsave_enabled : 1;
bool lbrv_enabled : 1;
bool pause_filter_enabled : 1;
bool pause_threshold_enabled : 1;
--
2.41.0.487.g6d72f3e995-goog
