Commit e59f75de authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Sean Christopherson
Browse files

KVM: x86/mmu: fix comment about mmu_unsync_pages_lock 



Fix the comment about what can and cannot happen when mmu_unsync_pages_lock
is not help.  The comment correctly mentions "clearing sp->unsync", but then
it talks about unsync going from 0 to 1.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Link: https://lore.kernel.org/r/20231125083400.1399197-5-pbonzini@redhat.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 250ce1b4

arch/x86/kvm/mmu/mmu.c

+2 −2
Original line number Diff line number Diff line
@@ -2850,9 +2850,9 @@ int mmu_try_to_unsync_pages(struct kvm *kvm, const struct kvm_memory_slot *slot, 
			/*

			 * Recheck after taking the spinlock, a different vCPU

			 * may have since marked the page unsync.  A false

			 * positive on the unprotected check above is not

			 * negative on the unprotected check above is not

			 * possible as clearing sp->unsync _must_ hold mmu_lock

			 * for write, i.e. unsync cannot transition from 0->1

			 * for write, i.e. unsync cannot transition from 1->0

			 * while this CPU holds mmu_lock for read (or write).

			 */

			if (READ_ONCE(sp->unsync))