Re: [PATCH v3 51/59] KVM: arm/arm64: GICv4: Add doorbell interrupt handling

Shannon Zhao
2017-09-06T09:06:29Z

On 2017/8/1 1:26, Marc Zyngier wrote:
> When a vPE is not running, a VLPI being made pending results in a
> doorbell interrupt being delivered. Let's handle this interrupt
> and update the pending_last flag that indicates that VLPIs are
> pending. The corresponding vcpu is also kicked into action.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
> virt/kvm/arm/vgic/vgic-v4.c | 34 ++++++++++++++++++++++++++++++++++
> 1 file changed, 34 insertions(+)
>
> diff --git a/virt/kvm/arm/vgic/vgic-v4.c b/virt/kvm/arm/vgic/vgic-v4.c
> index 534d3051a078..6af3cde6d7d4 100644
> --- a/virt/kvm/arm/vgic/vgic-v4.c
> +++ b/virt/kvm/arm/vgic/vgic-v4.c
> @@ -21,6 +21,19 @@
>
> #include "vgic.h"
>
> +static irqreturn_t vgic_v4_doorbell_handler(int irq, void *info)
> +{
> + struct kvm_vcpu *vcpu = info;
> +
> + if (!kvm_vgic_vcpu_pending_irq(vcpu)) {
> + vcpu->arch.vgic_cpu.vgic_v3.its_vpe.pending_last = true;
> + kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
> + kvm_vcpu_kick(vcpu);
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> int vgic_v4_init(struct kvm *kvm)
> {
> struct vgic_dist *dist = &kvm->arch.vgic;
> @@ -57,16 +70,37 @@ int vgic_v4_init(struct kvm *kvm)
> return ret;
> }
>
> + kvm_for_each_vcpu(i, vcpu, kvm) {
> + int irq = dist->its_vm.vpes[i]->irq;
> +
> + ret = request_irq(irq, vgic_v4_doorbell_handler,
> + 0, "vcpu", vcpu);
> + if (ret) {
> + kvm_err("failed to allocate vcpu IRQ%d\n", irq);
> + dist->its_vm.nr_vpes = i;
This overwirtes the nr_vpes while it uses kvm->online_vcpus in
its_alloc_vcpu_irqs to alloc irqs and if this fails it uses the
overwirten nr_vpes other than kvm->online_vcpus in its_free_vcpu_irqs to
free the irqs. So there will be memory leak on error path.

> + break;
> + }
> + }
> +
> + if (ret)
> + vgic_v4_teardown(kvm);
> +
> return ret;
> }
>
> void vgic_v4_teardown(struct kvm *kvm)
> {
> struct its_vm *its_vm = &kvm->arch.vgic.its_vm;
> + int i;
>
> if (!its_vm->vpes)
> return;
>
> + for (i = 0; i < its_vm->nr_vpes; i++) {
> + struct kvm_vcpu *vcpu = kvm_get_vcpu(kvm, i);
> + free_irq(its_vm->vpes[i]->irq, vcpu);
> + }
> +
> its_free_vcpu_irqs(its_vm);
> kfree(its_vm->vpes);
> its_vm->nr_vpes = 0;
>

Thanks,
--
Shannon