Commit cdbd4b40 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: VMX: Invalidate hv_tlb_eptp to denote an EPTP mismatch 



Drop the dedicated 'ept_pointers_match' field in favor of stuffing
'hv_tlb_eptp' with INVALID_PAGE to mark it as invalid, i.e. to denote
that there is at least one EPTP mismatch.  Use a local variable to
track whether or not a mismatch is detected so that hv_tlb_eptp can be
used to skip redundant flushes.

No functional change intended.

Reviewed-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20210305183123.3978098-7-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 446f7f11

arch/x86/kvm/vmx/vmx.c

+23 −12
Original line number Diff line number Diff line
@@ -500,32 +500,44 @@ static int hv_remote_flush_tlb_with_range(struct kvm *kvm, 
{

	struct kvm_vmx *kvm_vmx = to_kvm_vmx(kvm);

	struct kvm_vcpu *vcpu;

	int ret = 0, i;

	int ret = 0, i, nr_unique_valid_eptps;

	u64 tmp_eptp;



	spin_lock(&kvm_vmx->ept_pointer_lock);



	if (kvm_vmx->ept_pointers_match != EPT_POINTERS_MATCH) {

		kvm_vmx->ept_pointers_match = EPT_POINTERS_MATCH;

		kvm_vmx->hv_tlb_eptp = INVALID_PAGE;

	if (!VALID_PAGE(kvm_vmx->hv_tlb_eptp)) {

		nr_unique_valid_eptps = 0;



		/*

		 * Flush all valid EPTPs, and see if all vCPUs have converged

		 * on a common EPTP, in which case future flushes can skip the

		 * loop and flush the common EPTP.

		 */

		kvm_for_each_vcpu(i, vcpu, kvm) {

			tmp_eptp = to_vmx(vcpu)->ept_pointer;

			if (!VALID_PAGE(tmp_eptp) ||

			    tmp_eptp == kvm_vmx->hv_tlb_eptp)

				continue;



			if (!VALID_PAGE(kvm_vmx->hv_tlb_eptp))

			/*

			 * Set the tracked EPTP to the first valid EPTP.  Keep

			 * this EPTP for the entirety of the loop even if more

			 * EPTPs are encountered as a low effort optimization

			 * to avoid flushing the same (first) EPTP again.

			 */

			if (++nr_unique_valid_eptps == 1)

				kvm_vmx->hv_tlb_eptp = tmp_eptp;

			else

				kvm_vmx->ept_pointers_match

					= EPT_POINTERS_MISMATCH;



			ret |= hv_remote_flush_eptp(tmp_eptp, range);

		}

		if (kvm_vmx->ept_pointers_match == EPT_POINTERS_MISMATCH)



		/*

		 * The optimized flush of a single EPTP can't be used if there

		 * are multiple valid EPTPs (obviously).

		 */

		if (nr_unique_valid_eptps > 1)

			kvm_vmx->hv_tlb_eptp = INVALID_PAGE;

	} else if (VALID_PAGE(kvm_vmx->hv_tlb_eptp)) {

	} else {

		ret = hv_remote_flush_eptp(kvm_vmx->hv_tlb_eptp, range);

	}
@@ -3105,8 +3117,7 @@ static void vmx_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa, 
		if (kvm_x86_ops.tlb_remote_flush) {

			spin_lock(&to_kvm_vmx(kvm)->ept_pointer_lock);

			to_vmx(vcpu)->ept_pointer = eptp;

			to_kvm_vmx(kvm)->ept_pointers_match

				= EPT_POINTERS_CHECK;

			to_kvm_vmx(kvm)->hv_tlb_eptp = INVALID_PAGE;

			spin_unlock(&to_kvm_vmx(kvm)->ept_pointer_lock);

		}

arch/x86/kvm/vmx/vmx.h

+0 −7
Original line number Diff line number Diff line
@@ -338,12 +338,6 @@ struct vcpu_vmx { 
	} shadow_msr_intercept;

};



enum ept_pointers_status {

	EPT_POINTERS_CHECK = 0,

	EPT_POINTERS_MATCH = 1,

	EPT_POINTERS_MISMATCH = 2

};



struct kvm_vmx {

	struct kvm kvm;
@@ -352,7 +346,6 @@ struct kvm_vmx { 
	gpa_t ept_identity_map_addr;



	hpa_t hv_tlb_eptp;

	enum ept_pointers_status ept_pointers_match;

	spinlock_t ept_pointer_lock;

};