kvm: x86: Support selectively freeing either current or previous MMU root
kvm_mmu_free_roots() now takes a mask specifying which roots to free, so
that either one of the roots (active/previous) can be individually freed
when needed.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 0b77c23..262b0bc 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1287,6 +1287,10 @@ static inline int __kvm_irq_line_state(unsigned long *irq_state,
return !!(*irq_state);
}
+#define KVM_MMU_ROOT_CURRENT BIT(0)
+#define KVM_MMU_ROOT_PREVIOUS BIT(1)
+#define KVM_MMU_ROOTS_ALL (~0UL)
+
int kvm_pic_set_irq(struct kvm_pic *pic, int irq, int irq_source_id, int level);
void kvm_pic_clear_all(struct kvm_pic *pic, int irq_source_id);
@@ -1298,7 +1302,7 @@ void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu);
int kvm_mmu_load(struct kvm_vcpu *vcpu);
void kvm_mmu_unload(struct kvm_vcpu *vcpu);
void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu);
-void kvm_mmu_free_roots(struct kvm_vcpu *vcpu, bool free_prev_root);
+void kvm_mmu_free_roots(struct kvm_vcpu *vcpu, ulong roots_to_free);
gpa_t translate_nested_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u32 access,
struct x86_exception *exception);
gpa_t kvm_mmu_gva_to_gpa_read(struct kvm_vcpu *vcpu, gva_t gva,
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 6eeca91..0f6965c 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3438,14 +3438,18 @@ static void mmu_free_root_page(struct kvm *kvm, hpa_t *root_hpa,
*root_hpa = INVALID_PAGE;
}
-void kvm_mmu_free_roots(struct kvm_vcpu *vcpu, bool free_prev_root)
+/* roots_to_free must be some combination of the KVM_MMU_ROOT_* flags */
+void kvm_mmu_free_roots(struct kvm_vcpu *vcpu, ulong roots_to_free)
{
int i;
LIST_HEAD(invalid_list);
struct kvm_mmu *mmu = &vcpu->arch.mmu;
+ bool free_active_root = roots_to_free & KVM_MMU_ROOT_CURRENT;
+ bool free_prev_root = roots_to_free & KVM_MMU_ROOT_PREVIOUS;
- if (!VALID_PAGE(mmu->root_hpa) &&
- (!VALID_PAGE(mmu->prev_root.hpa) || !free_prev_root))
+ /* Before acquiring the MMU lock, see if we need to do any real work. */
+ if (!(free_active_root && VALID_PAGE(mmu->root_hpa)) &&
+ !(free_prev_root && VALID_PAGE(mmu->prev_root.hpa)))
return;
spin_lock(&vcpu->kvm->mmu_lock);
@@ -3454,15 +3458,19 @@ void kvm_mmu_free_roots(struct kvm_vcpu *vcpu, bool free_prev_root)
mmu_free_root_page(vcpu->kvm, &mmu->prev_root.hpa,
&invalid_list);
- if (mmu->shadow_root_level >= PT64_ROOT_4LEVEL &&
- (mmu->root_level >= PT64_ROOT_4LEVEL || mmu->direct_map)) {
- mmu_free_root_page(vcpu->kvm, &mmu->root_hpa, &invalid_list);
- } else {
- for (i = 0; i < 4; ++i)
- if (mmu->pae_root[i] != 0)
- mmu_free_root_page(vcpu->kvm, &mmu->pae_root[i],
- &invalid_list);
- mmu->root_hpa = INVALID_PAGE;
+ if (free_active_root) {
+ if (mmu->shadow_root_level >= PT64_ROOT_4LEVEL &&
+ (mmu->root_level >= PT64_ROOT_4LEVEL || mmu->direct_map)) {
+ mmu_free_root_page(vcpu->kvm, &mmu->root_hpa,
+ &invalid_list);
+ } else {
+ for (i = 0; i < 4; ++i)
+ if (mmu->pae_root[i] != 0)
+ mmu_free_root_page(vcpu->kvm,
+ &mmu->pae_root[i],
+ &invalid_list);
+ mmu->root_hpa = INVALID_PAGE;
+ }
}
kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
@@ -4109,7 +4117,7 @@ static void __kvm_mmu_new_cr3(struct kvm_vcpu *vcpu, gpa_t new_cr3,
bool skip_tlb_flush)
{
if (!fast_cr3_switch(vcpu, new_cr3, new_role, skip_tlb_flush))
- kvm_mmu_free_roots(vcpu, false);
+ kvm_mmu_free_roots(vcpu, KVM_MMU_ROOT_CURRENT);
}
void kvm_mmu_new_cr3(struct kvm_vcpu *vcpu, gpa_t new_cr3, bool skip_tlb_flush)
@@ -4885,7 +4893,7 @@ EXPORT_SYMBOL_GPL(kvm_mmu_load);
void kvm_mmu_unload(struct kvm_vcpu *vcpu)
{
- kvm_mmu_free_roots(vcpu, true);
+ kvm_mmu_free_roots(vcpu, KVM_MMU_ROOTS_ALL);
WARN_ON(VALID_PAGE(vcpu->arch.mmu.root_hpa));
}
EXPORT_SYMBOL_GPL(kvm_mmu_unload);