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Commit a336282d authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Paolo Bonzini
Browse files

x86/kvm/nVMX: introduce source data cache for kvm_init_shadow_ept_mmu() 



MMU re-initialization is expensive, in particular,
update_permission_bitmask() and update_pkru_bitmask() are.

Cache the data used to setup shadow EPT MMU and avoid full re-init when
it is unchanged.

Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 36d9594d

arch/x86/include/asm/kvm_host.h

+14 −0
Original line number Diff line number Diff line
@@ -283,7 +283,21 @@ union kvm_mmu_page_role { 
};



union kvm_mmu_extended_role {

/*

 * This structure complements kvm_mmu_page_role caching everything needed for

 * MMU configuration. If nothing in both these structures changed, MMU

 * re-configuration can be skipped. @valid bit is set on first usage so we don't

 * treat all-zero structure as valid data.

 */

	u32 word;

	struct {

		unsigned int valid:1;

		unsigned int execonly:1;

		unsigned int cr4_pse:1;

		unsigned int cr4_pke:1;

		unsigned int cr4_smap:1;

		unsigned int cr4_smep:1;

	};

};



union kvm_mmu_role {

arch/x86/kvm/mmu.c

+38 −15
Original line number Diff line number Diff line
@@ -4724,6 +4724,20 @@ static void paging32E_init_context(struct kvm_vcpu *vcpu, 
	paging64_init_context_common(vcpu, context, PT32E_ROOT_LEVEL);

}



static union kvm_mmu_extended_role kvm_calc_mmu_role_ext(struct kvm_vcpu *vcpu)

{

	union kvm_mmu_extended_role ext = {0};



	ext.cr4_smep = !!kvm_read_cr4_bits(vcpu, X86_CR4_SMEP);

	ext.cr4_smap = !!kvm_read_cr4_bits(vcpu, X86_CR4_SMAP);

	ext.cr4_pse = !!is_pse(vcpu);

	ext.cr4_pke = !!kvm_read_cr4_bits(vcpu, X86_CR4_PKE);



	ext.valid = 1;



	return ext;

}



static union kvm_mmu_page_role

kvm_calc_tdp_mmu_root_page_role(struct kvm_vcpu *vcpu)

{
@@ -4830,19 +4844,23 @@ void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu) 
}

EXPORT_SYMBOL_GPL(kvm_init_shadow_mmu);



static union kvm_mmu_page_role

kvm_calc_shadow_ept_root_page_role(struct kvm_vcpu *vcpu, bool accessed_dirty)

static union kvm_mmu_role

kvm_calc_shadow_ept_root_page_role(struct kvm_vcpu *vcpu, bool accessed_dirty,

				   bool execonly)

{

	union kvm_mmu_page_role role;

	union kvm_mmu_role role;



	/* Role is inherited from root_mmu */

	role.word = vcpu->arch.root_mmu.base_role.word;

	/* Base role is inherited from root_mmu */

	role.base.word = vcpu->arch.root_mmu.mmu_role.base.word;

	role.ext = kvm_calc_mmu_role_ext(vcpu);



	role.level = PT64_ROOT_4LEVEL;

	role.direct = false;

	role.ad_disabled = !accessed_dirty;

	role.guest_mode = true;

	role.access = ACC_ALL;

	role.base.level = PT64_ROOT_4LEVEL;

	role.base.direct = false;

	role.base.ad_disabled = !accessed_dirty;

	role.base.guest_mode = true;

	role.base.access = ACC_ALL;



	role.ext.execonly = execonly;



	return role;

}
@@ -4851,10 +4869,16 @@ void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly, 
			     bool accessed_dirty, gpa_t new_eptp)

{

	struct kvm_mmu *context = vcpu->arch.mmu;

	union kvm_mmu_page_role root_page_role =

		kvm_calc_shadow_ept_root_page_role(vcpu, accessed_dirty);

	union kvm_mmu_role new_role =

		kvm_calc_shadow_ept_root_page_role(vcpu, accessed_dirty,

						   execonly);



	__kvm_mmu_new_cr3(vcpu, new_eptp, new_role.base, false);



	new_role.base.word &= mmu_base_role_mask.word;

	if (new_role.as_u64 == context->mmu_role.as_u64)

		return;



	__kvm_mmu_new_cr3(vcpu, new_eptp, root_page_role, false);

	context->shadow_root_level = PT64_ROOT_4LEVEL;



	context->nx = true;
@@ -4866,8 +4890,7 @@ void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly, 
	context->update_pte = ept_update_pte;

	context->root_level = PT64_ROOT_4LEVEL;

	context->direct_map = false;

	context->mmu_role.base.word =

		root_page_role.word & mmu_base_role_mask.word;

	context->mmu_role.as_u64 = new_role.as_u64;



	update_permission_bitmask(vcpu, context, true);

	update_pkru_bitmask(vcpu, context, true);