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: Marc Zyngier maz@kernel.org --- arch/arm64/kvm/vgic/vgic-init.c | 29 ++++++++++++++--------------- 1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c index c8c3cb812783..ad7e86879eb9 100644 --- a/arch/arm64/kvm/vgic/vgic-init.c +++ b/arch/arm64/kvm/vgic/vgic-init.c @@ -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; }