Subject: [RFC PATCH 16/45] KVM: arm/arm64: vgic-new: Add PENDING registers handlers

From: [email-masked] (Christoffer Dall)
Date: Thu, 31 Mar 2016 11:35:51 +0200

On Fri, Mar 25, 2016 at 02:04:39AM +0000, Andre Przywara wrote:
> Signed-off-by: Andre Przywara <[email-masked]>
> ---
>  virt/kvm/arm/vgic/vgic_mmio.c | 87 ++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 85 insertions(+), 2 deletions(-)
> 
> diff --git a/virt/kvm/arm/vgic/vgic_mmio.c b/virt/kvm/arm/vgic/vgic_mmio.c
> index 0688a69..8514f92 100644
> --- a/virt/kvm/arm/vgic/vgic_mmio.c
> +++ b/virt/kvm/arm/vgic/vgic_mmio.c
> @@ -206,6 +206,89 @@ static int vgic_mmio_write_cenable(struct kvm_vcpu *vcpu,
>  	return 0;
>  }
>  
> +static int vgic_mmio_read_pending(struct kvm_vcpu *vcpu,
> +				  struct kvm_io_device *this,
> +				  gpa_t addr, int len, void *val)
> +{
> +	struct vgic_io_device *iodev = container_of(this,
> +						    struct vgic_io_device, dev);
> +	u32 intid = (addr - iodev->base_addr) * 8;
> +	u32 value = 0;
> +	int i;
> +
> +	if (iodev->redist_vcpu)
> +		vcpu = iodev->redist_vcpu;
> +
> +	/* Loop over all IRQs affected by this read */
> +	for (i = 0; i < len * 8; i++) {
> +		struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
> +
> +		spin_lock(&irq->irq_lock);
> +		if (irq->pending)
> +			value |= (1U << i);
> +		spin_unlock(&irq->irq_lock);

here there clearly is no need to take the lock (because a bool read is
atomic), but that should be explained in a one-line comment.

> +	}
> +
> +	write_mask32(value, addr & 3, len, val);
> +	return 0;
> +}
> +
> +static int vgic_mmio_write_spending(struct kvm_vcpu *vcpu,
> +				    struct kvm_io_device *this,
> +				    gpa_t addr, int len, const void *val)
> +{
> +	struct vgic_io_device *iodev = container_of(this,
> +						    struct vgic_io_device, dev);
> +	u32 intid = (addr - iodev->base_addr) * 8;
> +	int i;
> +
> +	if (iodev->redist_vcpu)
> +		vcpu = iodev->redist_vcpu;
> +
> +	for_each_set_bit(i, val, len * 8) {
> +		struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
> +
> +		spin_lock(&irq->irq_lock);
> +		irq->pending = true;
> +		if (irq->config == VGIC_CONFIG_LEVEL)
> +			irq->soft_pending = true;
> +
> +		vgic_queue_irq(vcpu->kvm, irq);
> +	}
> +
> +	return 0;
> +}
> +
> +static int vgic_mmio_write_cpending(struct kvm_vcpu *vcpu,
> +				    struct kvm_io_device *this,
> +				    gpa_t addr, int len, const void *val)
> +{
> +	struct vgic_io_device *iodev = container_of(this,
> +						    struct vgic_io_device, dev);
> +	u32 intid = (addr - iodev->base_addr) * 8;
> +	int i;
> +
> +	if (iodev->redist_vcpu)
> +		vcpu = iodev->redist_vcpu;
> +
> +	for_each_set_bit(i, val, len * 8) {
> +		struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
> +
> +		spin_lock(&irq->irq_lock);
> +
> +		if (irq->config == VGIC_CONFIG_LEVEL) {
> +			irq->soft_pending = false;
> +			irq->pending = irq->line_level;
> +		} else {
> +			irq->pending = false;
> +		}
> +		/* TODO: Does the exit/entry code take care of "unqueuing"? */

see previous patch comment

> +
> +		spin_unlock(&irq->irq_lock);
> +	}
> +	return 0;
> +}
> +
>  struct vgic_register_region vgic_v2_dist_registers[] = {
>  	REGISTER_DESC_WITH_LENGTH(GIC_DIST_CTRL,
>  		vgic_mmio_read_v2_misc, vgic_mmio_write_v2_misc, 12),
> @@ -216,9 +299,9 @@ struct vgic_register_region vgic_v2_dist_registers[] = {
>  	REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_ENABLE_CLEAR,
>  		vgic_mmio_read_enable, vgic_mmio_write_cenable, 1),
>  	REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_PENDING_SET,
> -		vgic_mmio_read_nyi, vgic_mmio_write_nyi, 1),
> +		vgic_mmio_read_pending, vgic_mmio_write_spending, 1),
>  	REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_PENDING_CLEAR,
> -		vgic_mmio_read_nyi, vgic_mmio_write_nyi, 1),
> +		vgic_mmio_read_pending, vgic_mmio_write_cpending, 1),
>  	REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_ACTIVE_SET,
>  		vgic_mmio_read_nyi, vgic_mmio_write_nyi, 1),
>  	REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_ACTIVE_CLEAR,
> -- 
> 2.7.3
>