Commit 01ad29d2 authored by Marc Zyngier's avatar Marc Zyngier Committed by Oliver Upton
Browse files

KVM: arm64: vgic: Simplify kvm_vgic_destroy() 



When destroying a vgic, we have rather cumbersome rules about
when slots_lock and config_lock are held, resulting in fun
buglets.

The first port of call is to simplify kvm_vgic_map_resources()
so that there is only one call to kvm_vgic_destroy() instead of
two, with the second only holding half of the locks.

For that, we kill the non-locking primitive and move the call
outside of the locking altogether. This doesn't change anything
(we re-acquire the locks and teardown the whole vgic), and
simplifies the code significantly.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231207151201.3028710-2-maz@kernel.org


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parent 33cc938e

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

+14 −15
Original line number Diff line number Diff line
@@ -382,26 +382,24 @@ void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu) 
	vgic_cpu->rd_iodev.base_addr = VGIC_ADDR_UNDEF;

}



static void __kvm_vgic_destroy(struct kvm *kvm)

void kvm_vgic_destroy(struct kvm *kvm)

{

	struct kvm_vcpu *vcpu;

	unsigned long i;



	lockdep_assert_held(&kvm->arch.config_lock);

	mutex_lock(&kvm->slots_lock);



	vgic_debug_destroy(kvm);



	kvm_for_each_vcpu(i, vcpu, kvm)

		kvm_vgic_vcpu_destroy(vcpu);



	mutex_lock(&kvm->arch.config_lock);



	kvm_vgic_dist_destroy(kvm);

}



void kvm_vgic_destroy(struct kvm *kvm)

{

	mutex_lock(&kvm->arch.config_lock);

	__kvm_vgic_destroy(kvm);

	mutex_unlock(&kvm->arch.config_lock);

	mutex_unlock(&kvm->slots_lock);

}



/**
@@ -469,25 +467,26 @@ int kvm_vgic_map_resources(struct kvm *kvm) 
		type = VGIC_V3;

	}



	if (ret) {

		__kvm_vgic_destroy(kvm);

	if (ret)

		goto out;

	}



	dist->ready = true;

	dist_base = dist->vgic_dist_base;

	mutex_unlock(&kvm->arch.config_lock);



	ret = vgic_register_dist_iodev(kvm, dist_base, type);

	if (ret) {

	if (ret)

		kvm_err("Unable to register VGIC dist MMIO regions\n");

		kvm_vgic_destroy(kvm);

	}

	mutex_unlock(&kvm->slots_lock);

	return ret;



	goto out_slots;

out:

	mutex_unlock(&kvm->arch.config_lock);

out_slots:

	mutex_unlock(&kvm->slots_lock);



	if (ret)

		kvm_vgic_destroy(kvm);



	return ret;

}