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Commit a1708ce8 authored by Andrea Arcangeli's avatar Andrea Arcangeli Committed by Avi Kivity
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KVM: Allow reading aliases with mmu_lock 



This allows the mmu notifier code to run unalias_gfn with only the
mmu_lock held.  Only alias writes need the mmu_lock held. Readers will
either take the slots_lock in read mode or the mmu_lock.

Signed-off-by: default avatarAndrea Arcangeli <andrea@qumranet.com>
Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent 6e86841d

arch/x86/kvm/x86.c

+2 −0
Original line number Original line Diff line number Diff line
@@ -1495,6 +1495,7 @@ static int kvm_vm_ioctl_set_memory_alias(struct kvm *kvm, 
		goto out;

		goto out;





	down_write(&kvm->slots_lock);

	down_write(&kvm->slots_lock);

	spin_lock(&kvm->mmu_lock);





	p = &kvm->arch.aliases[alias->slot];

	p = &kvm->arch.aliases[alias->slot];

	p->base_gfn = alias->guest_phys_addr >> PAGE_SHIFT;

	p->base_gfn = alias->guest_phys_addr >> PAGE_SHIFT;
@@ -1506,6 +1507,7 @@ static int kvm_vm_ioctl_set_memory_alias(struct kvm *kvm, 
			break;

			break;

	kvm->arch.naliases = n;

	kvm->arch.naliases = n;





	spin_unlock(&kvm->mmu_lock);

	kvm_mmu_zap_all(kvm);

	kvm_mmu_zap_all(kvm);





	up_write(&kvm->slots_lock);

	up_write(&kvm->slots_lock);