Re: [PATCH v4 21/26] KVM: arm/arm64: GICv4: Hook vPE scheduling into vgic flush/sync

Christoffer Dall
2017-10-26T15:24:45Z

On Fri, Oct 06, 2017 at 04:33:56PM +0100, Marc Zyngier wrote:
> The redistributor needs to be told which vPE is about to be run,
> and tells us whether there is any pending VLPI on exit.
>
> Let's add the scheduling calls to the vgic flush/sync functions,
> allowing the VLPIs to be delivered to the guest.
>

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>

> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
> virt/kvm/arm/vgic/vgic-v4.c | 39 +++++++++++++++++++++++++++++++++++++++
> virt/kvm/arm/vgic/vgic.c | 4 ++++
> virt/kvm/arm/vgic/vgic.h | 2 ++
> 3 files changed, 45 insertions(+)
>
> diff --git a/virt/kvm/arm/vgic/vgic-v4.c b/virt/kvm/arm/vgic/vgic-v4.c
> index 5ee69aec990a..68a2ef6df161 100644
> --- a/virt/kvm/arm/vgic/vgic-v4.c
> +++ b/virt/kvm/arm/vgic/vgic-v4.c
> @@ -130,6 +130,45 @@ void vgic_v4_teardown(struct kvm *kvm)
> its_vm->vpes = NULL;
> }
>
> +int vgic_v4_sync_hwstate(struct kvm_vcpu *vcpu)
> +{
> + if (!vgic_supports_direct_msis(vcpu->kvm))
> + return 0;
> +
> + return its_schedule_vpe(&vcpu->arch.vgic_cpu.vgic_v3.its_vpe, false);
> +}
> +
> +int vgic_v4_flush_hwstate(struct kvm_vcpu *vcpu)
> +{
> + int irq = vcpu->arch.vgic_cpu.vgic_v3.its_vpe.irq;
> + int err;
> +
> + if (!vgic_supports_direct_msis(vcpu->kvm))
> + return 0;
> +
> + /*
> + * Before making the VPE resident, make sure the redistributor
> + * corresponding to our current CPU expects us here. See the
> + * doc in drivers/irqchip/irq-gic-v4.c to understand how this
> + * turns into a VMOVP command at the ITS level.
> + */
> + err = irq_set_affinity(irq, cpumask_of(smp_processor_id()));
> + if (err)
> + return err;
> +
> + err = its_schedule_vpe(&vcpu->arch.vgic_cpu.vgic_v3.its_vpe, true);
> + if (err)
> + return err;
> +
> + /*
> + * Now that the VPE is resident, let's get rid of a potential
> + * doorbell interrupt that would still be pending.
> + */
> + err = irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, false);
> +
> + return err;
> +}
> +
> static struct vgic_its *vgic_get_its(struct kvm *kvm,
> struct kvm_kernel_irq_routing_entry *irq_entry)
> {
> diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
> index 0691a2250949..71ca0ff1b35a 100644
> --- a/virt/kvm/arm/vgic/vgic.c
> +++ b/virt/kvm/arm/vgic/vgic.c
> @@ -709,6 +709,8 @@ void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
> {
> struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
>
> + WARN_ON(vgic_v4_sync_hwstate(vcpu));
> +
> /* An empty ap_list_head implies used_lrs == 0 */
> if (list_empty(&vcpu->arch.vgic_cpu.ap_list_head))
> return;
> @@ -721,6 +723,8 @@ void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
> /* Flush our emulation state into the GIC hardware before entering the guest. */
> void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)
> {
> + WARN_ON(vgic_v4_flush_hwstate(vcpu));
> +
> /*
> * If there are no virtual interrupts active or pending for this
> * VCPU, then there is no work to do and we can bail out without
> diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
> index 1bd2e28ac097..1c65750892d7 100644
> --- a/virt/kvm/arm/vgic/vgic.h
> +++ b/virt/kvm/arm/vgic/vgic.h
> @@ -245,5 +245,7 @@ int update_lpi_config(struct kvm *kvm, struct vgic_irq *irq,
> bool vgic_supports_direct_msis(struct kvm *kvm);
> int vgic_v4_init(struct kvm *kvm);
> void vgic_v4_teardown(struct kvm *kvm);
> +int vgic_v4_sync_hwstate(struct kvm_vcpu *vcpu);
> +int vgic_v4_flush_hwstate(struct kvm_vcpu *vcpu);
>
> #endif
> --
> 2.14.1
>