Commit 8e86e736 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

Merge branch 'kvm-lockdep-common' into HEAD 



Introduce new mutex locking functions mutex_trylock_nest_lock() and
mutex_lock_killable_nest_lock() and use them to clean up locking
of all vCPUs for a VM.

For x86, this removes some complex code that was used instead
of lockdep's "nest_lock" feature.

For ARM and RISC-V, this removes a lockdep warning when the VM is
configured to have more than MAX_LOCK_DEPTH vCPUs, and removes a fair
amount of duplicate code by sharing the logic across all architectures.

Signed-off-by: default avatarPaolo BOnzini <pbonzini@redhat.com>
parents 4e02d4f9 4dbe28c0

arch/arm64/include/asm/kvm_host.h

+0 −3
Original line number Diff line number Diff line
@@ -1320,9 +1320,6 @@ int __init populate_sysreg_config(const struct sys_reg_desc *sr, 
				  unsigned int idx);

int __init populate_nv_trap_config(void);



bool lock_all_vcpus(struct kvm *kvm);

void unlock_all_vcpus(struct kvm *kvm);



void kvm_calculate_traps(struct kvm_vcpu *vcpu);



/* MMIO helpers */

arch/arm64/kvm/arch_timer.c

+2 −2
Original line number Diff line number Diff line
@@ -1766,7 +1766,7 @@ int kvm_vm_ioctl_set_counter_offset(struct kvm *kvm, 


	mutex_lock(&kvm->lock);



	if (lock_all_vcpus(kvm)) {

	if (!kvm_trylock_all_vcpus(kvm)) {

		set_bit(KVM_ARCH_FLAG_VM_COUNTER_OFFSET, &kvm->arch.flags);



		/*
@@ -1778,7 +1778,7 @@ int kvm_vm_ioctl_set_counter_offset(struct kvm *kvm, 
		kvm->arch.timer_data.voffset = offset->counter_offset;

		kvm->arch.timer_data.poffset = offset->counter_offset;



		unlock_all_vcpus(kvm);

		kvm_unlock_all_vcpus(kvm);

	} else {

		ret = -EBUSY;

	}

arch/arm64/kvm/arm.c

+0 −43
Original line number Diff line number Diff line
@@ -1924,49 +1924,6 @@ int kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) 
	}

}



/* unlocks vcpus from @vcpu_lock_idx and smaller */

static void unlock_vcpus(struct kvm *kvm, int vcpu_lock_idx)

{

	struct kvm_vcpu *tmp_vcpu;



	for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {

		tmp_vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx);

		mutex_unlock(&tmp_vcpu->mutex);

	}

}



void unlock_all_vcpus(struct kvm *kvm)

{

	lockdep_assert_held(&kvm->lock);



	unlock_vcpus(kvm, atomic_read(&kvm->online_vcpus) - 1);

}



/* Returns true if all vcpus were locked, false otherwise */

bool lock_all_vcpus(struct kvm *kvm)

{

	struct kvm_vcpu *tmp_vcpu;

	unsigned long c;



	lockdep_assert_held(&kvm->lock);



	/*

	 * Any time a vcpu is in an ioctl (including running), the

	 * core KVM code tries to grab the vcpu->mutex.

	 *

	 * By grabbing the vcpu->mutex of all VCPUs we ensure that no

	 * other VCPUs can fiddle with the state while we access it.

	 */

	kvm_for_each_vcpu(c, tmp_vcpu, kvm) {

		if (!mutex_trylock(&tmp_vcpu->mutex)) {

			unlock_vcpus(kvm, c - 1);

			return false;

		}

	}



	return true;

}



static unsigned long nvhe_percpu_size(void)

{

	return (unsigned long)CHOOSE_NVHE_SYM(__per_cpu_end) -

arch/arm64/kvm/vgic/vgic-init.c

+2 −2
Original line number Diff line number Diff line
@@ -88,7 +88,7 @@ int kvm_vgic_create(struct kvm *kvm, u32 type) 
	lockdep_assert_held(&kvm->lock);



	ret = -EBUSY;

	if (!lock_all_vcpus(kvm))

	if (kvm_trylock_all_vcpus(kvm))

		return ret;



	mutex_lock(&kvm->arch.config_lock);
@@ -142,7 +142,7 @@ int kvm_vgic_create(struct kvm *kvm, u32 type) 


out_unlock:

	mutex_unlock(&kvm->arch.config_lock);

	unlock_all_vcpus(kvm);

	kvm_unlock_all_vcpus(kvm);

	return ret;

}

arch/arm64/kvm/vgic/vgic-its.c

+4 −4
Original line number Diff line number Diff line
@@ -1971,7 +1971,7 @@ static int vgic_its_attr_regs_access(struct kvm_device *dev, 


	mutex_lock(&dev->kvm->lock);



	if (!lock_all_vcpus(dev->kvm)) {

	if (kvm_trylock_all_vcpus(dev->kvm)) {

		mutex_unlock(&dev->kvm->lock);

		return -EBUSY;

	}
@@ -2006,7 +2006,7 @@ static int vgic_its_attr_regs_access(struct kvm_device *dev, 
	}

out:

	mutex_unlock(&dev->kvm->arch.config_lock);

	unlock_all_vcpus(dev->kvm);

	kvm_unlock_all_vcpus(dev->kvm);

	mutex_unlock(&dev->kvm->lock);

	return ret;

}
@@ -2676,7 +2676,7 @@ static int vgic_its_ctrl(struct kvm *kvm, struct vgic_its *its, u64 attr) 


	mutex_lock(&kvm->lock);



	if (!lock_all_vcpus(kvm)) {

	if (kvm_trylock_all_vcpus(kvm)) {

		mutex_unlock(&kvm->lock);

		return -EBUSY;

	}
@@ -2698,7 +2698,7 @@ static int vgic_its_ctrl(struct kvm *kvm, struct vgic_its *its, u64 attr) 


	mutex_unlock(&its->its_lock);

	mutex_unlock(&kvm->arch.config_lock);

	unlock_all_vcpus(kvm);

	kvm_unlock_all_vcpus(kvm);

	mutex_unlock(&kvm->lock);

	return ret;

}