Re: [PATCH v5 21/26] KVM: arm/arm64: GICv4: Hook vPE scheduling into vgic flush/sync

Auger Eric
2017-11-07T22:14:29Z

Hi Marc,

On 07/11/2017 22:54, Auger Eric wrote:
> Hi Marc,
>
> On 27/10/2017 16:28, 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 1a2f2fcdfa67..d7fe610bb1f5 100644
>> --- a/virt/kvm/arm/vgic/vgic-v4.c
>> +++ b/virt/kvm/arm/vgic/vgic-v4.c
>> @@ -131,6 +131,45 @@ 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.
>> + */
> I don't get the above comment. Don't you set the affinity of the
> doorbell irq below?
Forget that one. I now recall the trick and see its_vpe_set_affinity()

Eric
>
> Thanks
>
> Eric
>> + 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 c4105f613f57..9cafb61b79af 100644
>> --- a/virt/kvm/arm/vgic/vgic.h
>> +++ b/virt/kvm/arm/vgic/vgic.h
>> @@ -243,5 +243,7 @@ struct vgic_its *vgic_msi_to_its(struct kvm *kvm, struct kvm_msi *msi);
>> 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
>>