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Commit 66d73e12 authored by Peter Feiner's avatar Peter Feiner Committed by Paolo Bonzini
Browse files

KVM: X86: MMU: no mmu_notifier_seq++ in kvm_age_hva 



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: default avatarPeter Feiner <pfeiner@google.com>
Reviewed-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
parent c63e4563

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);

}