KVM: nVMX: Don't flush TLB on nested VMX transition (9805c5f7) · Commits · 戴 / test

Unconditionally skip the TLB flush triggered when reusing a root for a nested transition as nested_vmx_transition_tlb_flush() ensures the TLB is flushed when needed, regardless of whether the MMU can reuse a cached root (or the last root). Signed-off-by:

Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200320212833.3507-35-sean.j.christopherson@intel.com> Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/mmu/mmu.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -5034,7 +5034,7 @@ void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
		kvm_calc_shadow_ept_root_page_role(vcpu, accessed_dirty,
		execonly, level);

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

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

arch/x86/kvm/vmx/nested.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -1143,10 +1143,12 @@ static int nested_vmx_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3, bool ne
		}

		/*
		* See nested_vmx_transition_mmu_sync for details on skipping the MMU sync.
		* Unconditionally skip the TLB flush on fast CR3 switch, all TLB
		* flushes are handled by nested_vmx_transition_tlb_flush(). See
		* nested_vmx_transition_mmu_sync for details on skipping the MMU sync.
		*/
		if (!nested_ept)
		kvm_mmu_new_cr3(vcpu, cr3, false,
		kvm_mmu_new_cr3(vcpu, cr3, true,
		!nested_vmx_transition_mmu_sync(vcpu));

		vcpu->arch.cr3 = cr3;

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