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Commit 960b3991 authored by Marcelo Tosatti's avatar Marcelo Tosatti Committed by Avi Kivity
Browse files

KVM: MMU: kvm_pv_mmu_op should not take mmap_sem 



kvm_pv_mmu_op should not take mmap_sem. All gfn_to_page() callers down
in the MMU processing will take it if necessary, so as it is it can
deadlock.

Apparently a leftover from the days before slots_lock.

Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent 1336028b

arch/x86/kvm/mmu.c

+0 −3
Original line number Diff line number Diff line
@@ -2173,8 +2173,6 @@ int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes, 
	int r;

	struct kvm_pv_mmu_op_buffer buffer;



	down_read(&current->mm->mmap_sem);



	buffer.ptr = buffer.buf;

	buffer.len = min_t(unsigned long, bytes, sizeof buffer.buf);

	buffer.processed = 0;
@@ -2194,7 +2192,6 @@ int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes, 
	r = 1;

out:

	*ret = buffer.processed;

	up_read(&current->mm->mmap_sem);

	return r;

}