Commit 01528db6 authored by Sean Christopherson's avatar Sean Christopherson
Browse files

KVM: Drop hack that "manually" informs lockdep of kvm->lock vs. vcpu->mutex 



Now that KVM takes vcpu->mutex inside kvm->lock when creating a vCPU, drop
the hack to manually inform lockdep of the kvm->lock => vcpu->mutex
ordering.

This effectively reverts commit 42a90008 ("KVM: Ensure lockdep knows
about kvm->lock vs. vcpu->mutex ordering rule").

Cc: Oliver Upton <oliver.upton@linux.dev>
Acked-by: default avatarWill Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20241009150455.1057573-7-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent e53dc37f

virt/kvm/kvm_main.c

+2 −7
Original line number Diff line number Diff line
@@ -4116,12 +4116,6 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, unsigned long id) 


	mutex_lock(&kvm->lock);



#ifdef CONFIG_LOCKDEP

	/* Ensure that lockdep knows vcpu->mutex is taken *inside* kvm->lock */

	mutex_lock(&vcpu->mutex);

	mutex_unlock(&vcpu->mutex);

#endif



	if (kvm_get_vcpu_by_id(kvm, id)) {

		r = -EEXIST;

		goto unlock_vcpu_destroy;
@@ -4138,7 +4132,8 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, unsigned long id) 
	 * so that userspace can't invoke vCPU ioctl()s until the vCPU is fully

	 * visible (per online_vcpus), e.g. so that KVM doesn't get tricked

	 * into a NULL-pointer dereference because KVM thinks the _current_

	 * vCPU doesn't exist.

	 * vCPU doesn't exist.  As a bonus, taking vcpu->mutex ensures lockdep

	 * knows it's taken *inside* kvm->lock.

	 */

	mutex_lock(&vcpu->mutex);

	kvm_get_kvm(kvm);