Re: [PATCH v5 18/23] KVM: arm64: GICv4.1: Add direct injection capability to SGI registers

[Auger Eric]

Hi Marc,
On 3/4/20 9:33 PM, Marc Zyngier wrote:
> Most of the GICv3 emulation code that deals with SGIs now has to be
> aware of the v4.1 capabilities in order to benefit from it.
> 
> Add such support, keyed on the interrupt having the hw flag set and
> being a SGI.
> 
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> ---
>  virt/kvm/arm/vgic/vgic-mmio-v3.c | 15 +++++-
>  virt/kvm/arm/vgic/vgic-mmio.c    | 88 ++++++++++++++++++++++++++++++--
>  2 files changed, 96 insertions(+), 7 deletions(-)
> 
> diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> index ebc218840fc2..de89da76a379 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
> +++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> @@ -6,6 +6,7 @@
>  #include <linux/irqchip/arm-gic-v3.h>
>  #include <linux/kvm.h>
>  #include <linux/kvm_host.h>
> +#include <linux/interrupt.h>
>  #include <kvm/iodev.h>
>  #include <kvm/arm_vgic.h>
>  
> @@ -942,8 +943,18 @@ void vgic_v3_dispatch_sgi(struct kvm_vcpu *vcpu, u64 reg, bool allow_group1)
>  		 * generate interrupts of either group.
>  		 */
>  		if (!irq->group || allow_group1) {
> -			irq->pending_latch = true;
> -			vgic_queue_irq_unlock(vcpu->kvm, irq, flags);
> +			if (!irq->hw) {
> +				irq->pending_latch = true;
> +				vgic_queue_irq_unlock(vcpu->kvm, irq, flags);
> +			} else {
> +				/* HW SGI? Ask the GIC to inject it */
> +				int err;
nit: add line
> +				err = irq_set_irqchip_state(irq->host_irq,
> +							    IRQCHIP_STATE_PENDING,
> +							    true);
> +				WARN_RATELIMIT(err, "IRQ %d", irq->host_irq);
> +				raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
> +			}
>  		} else {
>  			raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
>  		}
> diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
> index 97fb2a40e6ba..2199302597fa 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio.c
> +++ b/virt/kvm/arm/vgic/vgic-mmio.c
> @@ -5,6 +5,8 @@
>  
>  #include <linux/bitops.h>
>  #include <linux/bsearch.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
>  #include <linux/kvm.h>
>  #include <linux/kvm_host.h>
>  #include <kvm/iodev.h>
> @@ -59,6 +61,11 @@ unsigned long vgic_mmio_read_group(struct kvm_vcpu *vcpu,
>  	return value;
>  }
>  
> +static void vgic_update_vsgi(struct vgic_irq *irq)
> +{
> +	WARN_ON(its_prop_update_vsgi(irq->host_irq, irq->priority, irq->group));
> +}
> +
>  void vgic_mmio_write_group(struct kvm_vcpu *vcpu, gpa_t addr,
>  			   unsigned int len, unsigned long val)
>  {
> @@ -71,7 +78,12 @@ void vgic_mmio_write_group(struct kvm_vcpu *vcpu, gpa_t addr,
>  
>  		raw_spin_lock_irqsave(&irq->irq_lock, flags);
>  		irq->group = !!(val & BIT(i));
> -		vgic_queue_irq_unlock(vcpu->kvm, irq, flags);
> +		if (irq->hw && vgic_irq_is_sgi(irq->intid)) {
> +			vgic_update_vsgi(irq);
> +			raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
> +		} else {
> +			vgic_queue_irq_unlock(vcpu->kvm, irq, flags);
> +		}
>  
>  		vgic_put_irq(vcpu->kvm, irq);
>  	}
> @@ -113,7 +125,21 @@ void vgic_mmio_write_senable(struct kvm_vcpu *vcpu,
>  		struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
>  
>  		raw_spin_lock_irqsave(&irq->irq_lock, flags);
> -		if (vgic_irq_is_mapped_level(irq)) {
> +		if (irq->hw && vgic_irq_is_sgi(irq->intid)) {
> +			if (!irq->enabled) {
> +				struct irq_data *data;
> +
> +				irq->enabled = true;
> +				data = &irq_to_desc(irq->host_irq)->irq_data;
> +				while (irqd_irq_disabled(data))
> +					enable_irq(irq->host_irq);
could you explain me why the while() is requested?
> +			}
> +
> +			raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
> +			vgic_put_irq(vcpu->kvm, irq);
> +
> +			continue;
> +		} else if (vgic_irq_is_mapped_level(irq)) {
>  			bool was_high = irq->line_level;
>  
>  			/*
> @@ -148,6 +174,8 @@ void vgic_mmio_write_cenable(struct kvm_vcpu *vcpu,
>  		struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
>  
>  		raw_spin_lock_irqsave(&irq->irq_lock, flags);
> +		if (irq->hw && vgic_irq_is_sgi(irq->intid) && irq->enabled)
> +			disable_irq_nosync(irq->host_irq);
>  
>  		irq->enabled = false;
>  
> @@ -167,10 +195,22 @@ unsigned long vgic_mmio_read_pending(struct kvm_vcpu *vcpu,
>  	for (i = 0; i < len * 8; i++) {
>  		struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
>  		unsigned long flags;
> +		bool val;
>  
>  		raw_spin_lock_irqsave(&irq->irq_lock, flags);
> -		if (irq_is_pending(irq))
> -			value |= (1U << i);
> +		if (irq->hw && vgic_irq_is_sgi(irq->intid)) {
> +			int err;
> +
> +			val = false;
> +			err = irq_get_irqchip_state(irq->host_irq,
> +						    IRQCHIP_STATE_PENDING,
> +						    &val);
> +			WARN_RATELIMIT(err, "IRQ %d", irq->host_irq);
> +		} else {
> +			val = irq_is_pending(irq);
> +		}
> +
> +		value |= ((u32)val << i);
>  		raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
>  
>  		vgic_put_irq(vcpu->kvm, irq);
> @@ -215,6 +255,21 @@ void vgic_mmio_write_spending(struct kvm_vcpu *vcpu,
>  		}
>  
>  		raw_spin_lock_irqsave(&irq->irq_lock, flags);
> +
> +		if (irq->hw && vgic_irq_is_sgi(irq->intid)) {
> +			/* HW SGI? Ask the GIC to inject it */
> +			int err;
nit: extra line
> +			err = irq_set_irqchip_state(irq->host_irq,
> +						    IRQCHIP_STATE_PENDING,
> +						    true);
> +			WARN_RATELIMIT(err, "IRQ %d", irq->host_irq);
> +
> +			raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
> +			vgic_put_irq(vcpu->kvm, irq);
> +
> +			continue;
> +		}
> +
>  		if (irq->hw)
>  			vgic_hw_irq_spending(vcpu, irq, is_uaccess);
>  		else
> @@ -269,6 +324,20 @@ void vgic_mmio_write_cpending(struct kvm_vcpu *vcpu,
>  
>  		raw_spin_lock_irqsave(&irq->irq_lock, flags);
>  
> +		if (irq->hw && vgic_irq_is_sgi(irq->intid)) {
> +			/* HW SGI? Ask the GIC to clear its pending bit */
> +			int err;
> +			err = irq_set_irqchip_state(irq->host_irq,
> +						    IRQCHIP_STATE_PENDING,
> +						    false);
> +			WARN_RATELIMIT(err, "IRQ %d", irq->host_irq);
> +
> +			raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
> +			vgic_put_irq(vcpu->kvm, irq);
> +
> +			continue;
> +		}
> +
>  		if (irq->hw)
>  			vgic_hw_irq_cpending(vcpu, irq, is_uaccess);
>  		else
> @@ -318,8 +387,15 @@ static void vgic_mmio_change_active(struct kvm_vcpu *vcpu, struct vgic_irq *irq,
>  
>  	raw_spin_lock_irqsave(&irq->irq_lock, flags);
>  
> -	if (irq->hw) {
> +	if (irq->hw && !vgic_irq_is_sgi(irq->intid)) {
>  		vgic_hw_irq_change_active(vcpu, irq, active, !requester_vcpu);
> +	} else if (irq->hw && vgic_irq_is_sgi(irq->intid)) {
> +		/*
> +		 * GICv4.1 VSGI feature doesn't track an active state,
> +		 * so let's not kid ourselves, there is nothing we can
> +		 * do here.
> +		 */
> +		irq->active = false;
>  	} else {
>  		u32 model = vcpu->kvm->arch.vgic.vgic_model;
>  		u8 active_source;
> @@ -493,6 +569,8 @@ void vgic_mmio_write_priority(struct kvm_vcpu *vcpu,
>  		raw_spin_lock_irqsave(&irq->irq_lock, flags);
>  		/* Narrow the priority range to what we actually support */
>  		irq->priority = (val >> (i * 8)) & GENMASK(7, 8 - VGIC_PRI_BITS);
> +		if (irq->hw && vgic_irq_is_sgi(irq->intid))
> +			vgic_update_vsgi(irq);
>  		raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
>  
>  		vgic_put_irq(vcpu->kvm, irq);
> 
Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>

Thanks

Eric