KVM: SVM: Document the ASID logic in svm_flush_tlb() (4a41e43c) · Commits · 戴 / test

Add a comment in svm_flush_tlb() to document why it flushes only the current ASID, even when it is invoked when flushing remote TLBs. Cc: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by:

Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200320212833.3507-22-sean.j.christopherson@intel.com> Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/svm/svm.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -3157,6 +3157,13 @@ void svm_flush_tlb(struct kvm_vcpu *vcpu)
		{
		struct vcpu_svm *svm = to_svm(vcpu);

		/*
		* Flush only the current ASID even if the TLB flush was invoked via
		* kvm_flush_remote_tlbs(). Although flushing remote TLBs requires all
		* ASIDs to be flushed, KVM uses a single ASID for L1 and L2, and
		* unconditionally does a TLB flush on both nested VM-Enter and nested
		* VM-Exit (via kvm_mmu_reset_context()).
		*/
		if (static_cpu_has(X86_FEATURE_FLUSHBYASID))
		svm->vmcb->control.tlb_ctl = TLB_CONTROL_FLUSH_ASID;
		else

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