Commit b869855b authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: x86/mmu: Move fast_cr3_switch() side effects to __kvm_mmu_new_cr3() 



Handle the side effects of a fast CR3 (PGD) switch up a level in
__kvm_mmu_new_cr3(), which is the only caller of fast_cr3_switch().

This consolidates handling all side effects in __kvm_mmu_new_cr3()
(where freeing the current root when KVM can't do a fast switch is
already handled), and ameliorates the pain of adding a second boolean in
a future patch to provide a separate "skip" override for the MMU sync.

Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200320212833.3507-31-sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 4de1f9d4

arch/x86/kvm/mmu/mmu.c

+31 −38
Original line number Diff line number Diff line
@@ -4284,8 +4284,7 @@ static bool cached_root_available(struct kvm_vcpu *vcpu, gpa_t new_cr3, 
}



static bool fast_cr3_switch(struct kvm_vcpu *vcpu, gpa_t new_cr3,

			    union kvm_mmu_page_role new_role,

			    bool skip_tlb_flush)

			    union kvm_mmu_page_role new_role)

{

	struct kvm_mmu *mmu = vcpu->arch.mmu;
@@ -4295,50 +4294,44 @@ static bool fast_cr3_switch(struct kvm_vcpu *vcpu, gpa_t new_cr3, 
	 * later if necessary.

	 */

	if (mmu->shadow_root_level >= PT64_ROOT_4LEVEL &&

	    mmu->root_level >= PT64_ROOT_4LEVEL) {

		if (mmu_check_root(vcpu, new_cr3 >> PAGE_SHIFT))

	    mmu->root_level >= PT64_ROOT_4LEVEL)

		return !mmu_check_root(vcpu, new_cr3 >> PAGE_SHIFT) &&

		       cached_root_available(vcpu, new_cr3, new_role);



	return false;

}



static void __kvm_mmu_new_cr3(struct kvm_vcpu *vcpu, gpa_t new_cr3,

			      union kvm_mmu_page_role new_role,

			      bool skip_tlb_flush)

{

	if (!fast_cr3_switch(vcpu, new_cr3, new_role)) {

		kvm_mmu_free_roots(vcpu, vcpu->arch.mmu, KVM_MMU_ROOT_CURRENT);

		return;

	}



		if (cached_root_available(vcpu, new_cr3, new_role)) {

	/*

			 * It is possible that the cached previous root page is

			 * obsolete because of a change in the MMU generation

			 * number. However, changing the generation number is

			 * accompanied by KVM_REQ_MMU_RELOAD, which will free

			 * the root set here and allocate a new one.

	 * It's possible that the cached previous root page is obsolete because

	 * of a change in the MMU generation number. However, changing the

	 * generation number is accompanied by KVM_REQ_MMU_RELOAD, which will

	 * free the root set here and allocate a new one.

	 */

	kvm_make_request(KVM_REQ_LOAD_MMU_PGD, vcpu);



	if (!skip_tlb_flush) {

		kvm_make_request(KVM_REQ_MMU_SYNC, vcpu);

		kvm_make_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu);

	}



	/*

			 * The last MMIO access's GVA and GPA are cached in the

			 * VCPU. When switching to a new CR3, that GVA->GPA

			 * mapping may no longer be valid. So clear any cached

			 * MMIO info even when we don't need to sync the shadow

			 * page tables.

	 * The last MMIO access's GVA and GPA are cached in the VCPU. When

	 * switching to a new CR3, that GVA->GPA mapping may no longer be

	 * valid. So clear any cached MMIO info even when we don't need to sync

	 * the shadow page tables.

	 */

	vcpu_clear_mmio_info(vcpu, MMIO_GVA_ANY);



			__clear_sp_write_flooding_count(

				page_header(mmu->root_hpa));



			return true;

		}

	}



	return false;

}



static void __kvm_mmu_new_cr3(struct kvm_vcpu *vcpu, gpa_t new_cr3,

			      union kvm_mmu_page_role new_role,

			      bool skip_tlb_flush)

{

	if (!fast_cr3_switch(vcpu, new_cr3, new_role, skip_tlb_flush))

		kvm_mmu_free_roots(vcpu, vcpu->arch.mmu,

				   KVM_MMU_ROOT_CURRENT);

	__clear_sp_write_flooding_count(page_header(vcpu->arch.mmu->root_hpa));

}



void kvm_mmu_new_cr3(struct kvm_vcpu *vcpu, gpa_t new_cr3, bool skip_tlb_flush)

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