KVM: X86: MMU: no mmu_notifier_seq++ in kvm_age_hva (66d73e12) · Commits · 戴 / test

The MMU notifier sequence number keeps GPA->HPA mappings in sync when GPA->HPA lookups are done outside of the MMU lock (e.g., in tdp_page_fault). Since kvm_age_hva doesn't change GPA->HPA, it's unnecessary to increment the sequence number. Signed-off-by:

Peter Feiner <pfeiner@google.com> Reviewed-by:

Paolo Bonzini <pbonzini@redhat.com> Signed-off-by:

Radim Krčmář <rkrcmar@redhat.com>

arch/x86/kvm/mmu.c

+1 −9

Original line number	Diff line number	Diff line
		@@ -1660,17 +1660,9 @@ int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end)
		* This has some overhead, but not as much as the cost of swapping
		* out actively used pages or breaking up actively used hugepages.
		*/
		if (!shadow_accessed_mask) {
		/*
		* We are holding the kvm->mmu_lock, and we are blowing up
		* shadow PTEs. MMU notifier consumers need to be kept at bay.
		* This is correct as long as we don't decouple the mmu_lock
		* protected regions (like invalidate_range_start\|end does).
		*/
		kvm->mmu_notifier_seq++;
		if (!shadow_accessed_mask)
		return kvm_handle_hva_range(kvm, start, end, 0,
		kvm_unmap_rmapp);
		}

		return kvm_handle_hva_range(kvm, start, end, 0, kvm_age_rmapp);
		}

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