Use the governed feature framework to track whether or not the guest can
use 1GiB pages, and drop the one-off helper that wraps the surprisingly
non-trivial logic surrounding 1GiB page usage in the guest.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/cpuid.c | 17 +++++++++++++++++
arch/x86/kvm/governed_features.h | 2 ++
arch/x86/kvm/mmu/mmu.c | 20 +++-----------------
3 files changed, 22 insertions(+), 17 deletions(-)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index ef826568c222..f74d6c404551 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -312,11 +312,28 @@ static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *apic = vcpu->arch.apic;
struct kvm_cpuid_entry2 *best;
+ bool allow_gbpages;
BUILD_BUG_ON(KVM_NR_GOVERNED_FEATURES > KVM_MAX_NR_GOVERNED_FEATURES);
bitmap_zero(vcpu->arch.governed_features.enabled,
KVM_MAX_NR_GOVERNED_FEATURES);
+ /*
+ * If TDP is enabled, let the guest use GBPAGES if they're supported in
+ * hardware. The hardware page walker doesn't let KVM disable GBPAGES,
+ * i.e. won't treat them as reserved, and KVM doesn't redo the GVA->GPA
+ * walk for performance and complexity reasons. Not to mention KVM
+ * _can't_ solve the problem because GVA->GPA walks aren't visible to
+ * KVM once a TDP translation is installed. Mimic hardware behavior so
+ * that KVM's is at least consistent, i.e. doesn't randomly inject #PF.
+ * If TDP is disabled, honor *only* guest CPUID as KVM has full control
+ * and can install smaller shadow pages if the host lacks 1GiB support.
+ */
+ allow_gbpages = tdp_enabled ? boot_cpu_has(X86_FEATURE_GBPAGES) :
+ guest_cpuid_has(vcpu, X86_FEATURE_GBPAGES);
+ if (allow_gbpages)
+ kvm_governed_feature_set(vcpu, X86_FEATURE_GBPAGES);
+
best = kvm_find_cpuid_entry(vcpu, 1);
if (best && apic) {
if (cpuid_entry_has(best, X86_FEATURE_TSC_DEADLINE_TIMER))
diff --git a/arch/x86/kvm/governed_features.h b/arch/x86/kvm/governed_features.h
index 40ce8e6608cd..b29c15d5e038 100644
--- a/arch/x86/kvm/governed_features.h
+++ b/arch/x86/kvm/governed_features.h
@@ -5,5 +5,7 @@ BUILD_BUG()
#define KVM_GOVERNED_X86_FEATURE(x) KVM_GOVERNED_FEATURE(X86_FEATURE_##x)
+KVM_GOVERNED_X86_FEATURE(GBPAGES)
+
#undef KVM_GOVERNED_X86_FEATURE
#undef KVM_GOVERNED_FEATURE
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index ec169f5c7dce..7b9104b054bc 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4808,28 +4808,13 @@ static void __reset_rsvds_bits_mask(struct rsvd_bits_validate *rsvd_check,
}
}
-static bool guest_can_use_gbpages(struct kvm_vcpu *vcpu)
-{
- /*
- * If TDP is enabled, let the guest use GBPAGES if they're supported in
- * hardware. The hardware page walker doesn't let KVM disable GBPAGES,
- * i.e. won't treat them as reserved, and KVM doesn't redo the GVA->GPA
- * walk for performance and complexity reasons. Not to mention KVM
- * _can't_ solve the problem because GVA->GPA walks aren't visible to
- * KVM once a TDP translation is installed. Mimic hardware behavior so
- * that KVM's is at least consistent, i.e. doesn't randomly inject #PF.
- */
- return tdp_enabled ? boot_cpu_has(X86_FEATURE_GBPAGES) :
- guest_cpuid_has(vcpu, X86_FEATURE_GBPAGES);
-}
-
static void reset_guest_rsvds_bits_mask(struct kvm_vcpu *vcpu,
struct kvm_mmu *context)
{
__reset_rsvds_bits_mask(&context->guest_rsvd_check,
vcpu->arch.reserved_gpa_bits,
context->cpu_role.base.level, is_efer_nx(context),
- guest_can_use_gbpages(vcpu),
+ guest_can_use(vcpu, X86_FEATURE_GBPAGES),
is_cr4_pse(context),
guest_cpuid_is_amd_or_hygon(vcpu));
}
@@ -4906,7 +4891,8 @@ static void reset_shadow_zero_bits_mask(struct kvm_vcpu *vcpu,
__reset_rsvds_bits_mask(shadow_zero_check, reserved_hpa_bits(),
context->root_role.level,
context->root_role.efer_nx,
- guest_can_use_gbpages(vcpu), is_pse, is_amd);
+ guest_can_use(vcpu, X86_FEATURE_GBPAGES),
+ is_pse, is_amd);
if (!shadow_me_mask)
return;
--
2.41.0.487.g6d72f3e995-goog
