Commit 08fb59d8 authored by Junaid Shahid's avatar Junaid Shahid Committed by Paolo Bonzini
Browse files

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: default avatarJunaid Shahid <junaids@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 7eb77e9f

arch/x86/include/asm/kvm_host.h

+5 −1
Original line number Diff line number Diff line
@@ -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,

arch/x86/kvm/mmu.c

+22 −14
Original line number Diff line number Diff line
@@ -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);
@@ -3454,16 +3458,20 @@ 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 (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);

			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],

					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);

	spin_unlock(&vcpu->kvm->mmu_lock);
@@ -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);