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Commit 5a4c9288 authored by Marcelo Tosatti's avatar Marcelo Tosatti Committed by Avi Kivity
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KVM: mmu_shrink: kvm_mmu_zap_page requires slots_lock to be held 



kvm_mmu_zap_page() needs slots lock held (rmap_remove->gfn_to_memslot,
for example).

Since kvm_lock spinlock is held in mmu_shrink(), do a non-blocking
down_read_trylock().

Untested.

Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent 7e37c299

arch/x86/kvm/mmu.c

+3 −0
Original line number Diff line number Diff line
@@ -1987,6 +1987,8 @@ static int mmu_shrink(int nr_to_scan, gfp_t gfp_mask) 
	list_for_each_entry(kvm, &vm_list, vm_list) {

		int npages;



		if (!down_read_trylock(&kvm->slots_lock))

			continue;

		spin_lock(&kvm->mmu_lock);

		npages = kvm->arch.n_alloc_mmu_pages -

			 kvm->arch.n_free_mmu_pages;
@@ -1999,6 +2001,7 @@ static int mmu_shrink(int nr_to_scan, gfp_t gfp_mask) 
		nr_to_scan--;



		spin_unlock(&kvm->mmu_lock);

		up_read(&kvm->slots_lock);

	}

	if (kvm_freed)

		list_move_tail(&kvm_freed->vm_list, &vm_list);