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Commit e08d8d29 authored by Julien Thierry's avatar Julien Thierry Committed by Christoffer Dall
Browse files

KVM: arm/arm64: vgic: Make vgic_cpu->ap_list_lock a raw_spinlock 



vgic_cpu->ap_list_lock must always be taken with interrupts disabled as
it is used in interrupt context.

For configurations such as PREEMPT_RT_FULL, this means that it should
be a raw_spinlock since RT spinlocks are interruptible.

Signed-off-by: default avatarJulien Thierry <julien.thierry@arm.com>
Acked-by: default avatarChristoffer Dall <christoffer.dall@arm.com>
Acked-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarChristoffer Dall <christoffer.dall@arm.com>
parent fc3bc475

include/kvm/arm_vgic.h

+1 −1
Original line number Diff line number Diff line
@@ -307,7 +307,7 @@ struct vgic_cpu { 
	unsigned int used_lrs;

	struct vgic_irq private_irqs[VGIC_NR_PRIVATE_IRQS];



	spinlock_t ap_list_lock;	/* Protects the ap_list */

	raw_spinlock_t ap_list_lock;	/* Protects the ap_list */



	/*

	 * List of IRQs that this VCPU should consider because they are either

virt/kvm/arm/vgic/vgic-init.c

+1 −1
Original line number Diff line number Diff line
@@ -206,7 +206,7 @@ int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu) 
	vgic_cpu->sgi_iodev.base_addr = VGIC_ADDR_UNDEF;



	INIT_LIST_HEAD(&vgic_cpu->ap_list_head);

	spin_lock_init(&vgic_cpu->ap_list_lock);

	raw_spin_lock_init(&vgic_cpu->ap_list_lock);



	/*

	 * Enable and configure all SGIs to be edge-triggered and

virt/kvm/arm/vgic/vgic.c

+19 −18
Original line number Diff line number Diff line
@@ -54,11 +54,11 @@ struct vgic_global kvm_vgic_global_state __ro_after_init = { 
 * When taking more than one ap_list_lock at the same time, always take the

 * lowest numbered VCPU's ap_list_lock first, so:

 *   vcpuX->vcpu_id < vcpuY->vcpu_id:

 *     spin_lock(vcpuX->arch.vgic_cpu.ap_list_lock);

 *     spin_lock(vcpuY->arch.vgic_cpu.ap_list_lock);

 *     raw_spin_lock(vcpuX->arch.vgic_cpu.ap_list_lock);

 *     raw_spin_lock(vcpuY->arch.vgic_cpu.ap_list_lock);

 *

 * Since the VGIC must support injecting virtual interrupts from ISRs, we have

 * to use the spin_lock_irqsave/spin_unlock_irqrestore versions of outer

 * to use the raw_spin_lock_irqsave/raw_spin_unlock_irqrestore versions of outer

 * spinlocks for any lock that may be taken while injecting an interrupt.

 */
@@ -351,7 +351,7 @@ bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq, 


	/* someone can do stuff here, which we re-check below */



	spin_lock_irqsave(&vcpu->arch.vgic_cpu.ap_list_lock, flags);

	raw_spin_lock_irqsave(&vcpu->arch.vgic_cpu.ap_list_lock, flags);

	raw_spin_lock(&irq->irq_lock);



	/*
@@ -368,7 +368,8 @@ bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq, 


	if (unlikely(irq->vcpu || vcpu != vgic_target_oracle(irq))) {

		raw_spin_unlock(&irq->irq_lock);

		spin_unlock_irqrestore(&vcpu->arch.vgic_cpu.ap_list_lock, flags);

		raw_spin_unlock_irqrestore(&vcpu->arch.vgic_cpu.ap_list_lock,

					   flags);



		raw_spin_lock_irqsave(&irq->irq_lock, flags);

		goto retry;
@@ -383,7 +384,7 @@ bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq, 
	irq->vcpu = vcpu;



	raw_spin_unlock(&irq->irq_lock);

	spin_unlock_irqrestore(&vcpu->arch.vgic_cpu.ap_list_lock, flags);

	raw_spin_unlock_irqrestore(&vcpu->arch.vgic_cpu.ap_list_lock, flags);



	kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);

	kvm_vcpu_kick(vcpu);
@@ -597,7 +598,7 @@ static void vgic_prune_ap_list(struct kvm_vcpu *vcpu) 
	DEBUG_SPINLOCK_BUG_ON(!irqs_disabled());



retry:

	spin_lock(&vgic_cpu->ap_list_lock);

	raw_spin_lock(&vgic_cpu->ap_list_lock);



	list_for_each_entry_safe(irq, tmp, &vgic_cpu->ap_list_head, ap_list) {

		struct kvm_vcpu *target_vcpu, *vcpuA, *vcpuB;
@@ -638,7 +639,7 @@ static void vgic_prune_ap_list(struct kvm_vcpu *vcpu) 
		/* This interrupt looks like it has to be migrated. */



		raw_spin_unlock(&irq->irq_lock);

		spin_unlock(&vgic_cpu->ap_list_lock);

		raw_spin_unlock(&vgic_cpu->ap_list_lock);



		/*

		 * Ensure locking order by always locking the smallest
@@ -652,8 +653,8 @@ static void vgic_prune_ap_list(struct kvm_vcpu *vcpu) 
			vcpuB = vcpu;

		}



		spin_lock(&vcpuA->arch.vgic_cpu.ap_list_lock);

		spin_lock_nested(&vcpuB->arch.vgic_cpu.ap_list_lock,

		raw_spin_lock(&vcpuA->arch.vgic_cpu.ap_list_lock);

		raw_spin_lock_nested(&vcpuB->arch.vgic_cpu.ap_list_lock,

				      SINGLE_DEPTH_NESTING);

		raw_spin_lock(&irq->irq_lock);
@@ -676,8 +677,8 @@ static void vgic_prune_ap_list(struct kvm_vcpu *vcpu) 
		}



		raw_spin_unlock(&irq->irq_lock);

		spin_unlock(&vcpuB->arch.vgic_cpu.ap_list_lock);

		spin_unlock(&vcpuA->arch.vgic_cpu.ap_list_lock);

		raw_spin_unlock(&vcpuB->arch.vgic_cpu.ap_list_lock);

		raw_spin_unlock(&vcpuA->arch.vgic_cpu.ap_list_lock);



		if (target_vcpu_needs_kick) {

			kvm_make_request(KVM_REQ_IRQ_PENDING, target_vcpu);
@@ -687,7 +688,7 @@ static void vgic_prune_ap_list(struct kvm_vcpu *vcpu) 
		goto retry;

	}



	spin_unlock(&vgic_cpu->ap_list_lock);

	raw_spin_unlock(&vgic_cpu->ap_list_lock);

}



static inline void vgic_fold_lr_state(struct kvm_vcpu *vcpu)
@@ -872,9 +873,9 @@ void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu) 


	DEBUG_SPINLOCK_BUG_ON(!irqs_disabled());



	spin_lock(&vcpu->arch.vgic_cpu.ap_list_lock);

	raw_spin_lock(&vcpu->arch.vgic_cpu.ap_list_lock);

	vgic_flush_lr_state(vcpu);

	spin_unlock(&vcpu->arch.vgic_cpu.ap_list_lock);

	raw_spin_unlock(&vcpu->arch.vgic_cpu.ap_list_lock);



	if (can_access_vgic_from_kernel())

		vgic_restore_state(vcpu);
@@ -918,7 +919,7 @@ int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu) 


	vgic_get_vmcr(vcpu, &vmcr);



	spin_lock_irqsave(&vgic_cpu->ap_list_lock, flags);

	raw_spin_lock_irqsave(&vgic_cpu->ap_list_lock, flags);



	list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {

		raw_spin_lock(&irq->irq_lock);
@@ -931,7 +932,7 @@ int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu) 
			break;

	}



	spin_unlock_irqrestore(&vgic_cpu->ap_list_lock, flags);

	raw_spin_unlock_irqrestore(&vgic_cpu->ap_list_lock, flags);



	return pending;

}