[RFC PATCH 14/45] KVM: arm/arm64: vgic-new: Add CTLR, TYPER and IIDR handlers

[Christoffer Dall]

On Fri, Mar 25, 2016 at 02:04:37AM +0000, Andre Przywara wrote:
> Signed-off-by: Andre Przywara <andre.przywara at arm.com>
> ---
>  virt/kvm/arm/vgic/vgic.h      |  3 +++
>  virt/kvm/arm/vgic/vgic_mmio.c | 49 ++++++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 51 insertions(+), 1 deletion(-)
> 
> diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
> index a462e2b..57aea8f 100644
> --- a/virt/kvm/arm/vgic/vgic.h
> +++ b/virt/kvm/arm/vgic/vgic.h
> @@ -16,6 +16,9 @@
>  #ifndef __KVM_ARM_VGIC_NEW_H__
>  #define __KVM_ARM_VGIC_NEW_H__
>  
> +#define PRODUCT_ID_KVM		0x4b	/* ASCII code K */
> +#define IMPLEMENTER_ARM		0x43b
> +
>  struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,
>  			      u32 intid);
>  bool vgic_queue_irq(struct kvm *kvm, struct vgic_irq *irq);
> diff --git a/virt/kvm/arm/vgic/vgic_mmio.c b/virt/kvm/arm/vgic/vgic_mmio.c
> index e1fd17f..e62366e 100644
> --- a/virt/kvm/arm/vgic/vgic_mmio.c
> +++ b/virt/kvm/arm/vgic/vgic_mmio.c
> @@ -82,9 +82,56 @@ static int vgic_mmio_write_nyi(struct kvm_vcpu *vcpu,
>  	return 0;
>  }
>  
> +static int vgic_mmio_read_v2_misc(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 value;
> +
> +	switch ((addr - iodev->base_addr) & ~3) {
> +	case 0x0:
> +		value = vcpu->kvm->arch.vgic.enabled ? GICD_ENABLE : 0;
> +		break;
> +	case 0x4:
> +		value = vcpu->kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS;
> +		value = (value >> 5) - 1;
> +		value |= (atomic_read(&vcpu->kvm->online_vcpus) - 1) << 5;
> +		break;
> +	case 0x8:
> +		value = (PRODUCT_ID_KVM << 24) | (IMPLEMENTER_ARM << 0);
> +		break;
> +	default:
> +		return 0;
> +	}
> +
> +	write_mask32(value, addr & 3, len, val);
> +	return 0;
> +}
> +
> +static int vgic_mmio_write_v2_misc(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);
> +	/*
> +	 * GICD_TYPER and GICD_IIDR are read-only, the upper three bytes of
> +	 * GICD_CTLR are reserved.
> +	 */
> +	if (addr - iodev->base_addr >= 1)
> +		return 0;
> +
> +	vcpu->kvm->arch.vgic.enabled = (*(u32 *)val) ? true : false;
> +	/* TODO: is there anything to trigger at this point? */

I guess we should actually check if the vgic is enabled in PATH 11, and
we should kick all VCPUs (or at least those with something pending) if
we went from disabled to enabled?

We should probably also check this in the sync function...

Or do we enforce this enabled bool somewhere else that I missed?

> +
> +	return 0;
> +}
> +
>  struct vgic_register_region vgic_v2_dist_registers[] = {
>  	REGISTER_DESC_WITH_LENGTH(GIC_DIST_CTRL,
> -		vgic_mmio_read_nyi, vgic_mmio_write_nyi, 12),
> +		vgic_mmio_read_v2_misc, vgic_mmio_write_v2_misc, 12),
>  	REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_IGROUP,
>  		vgic_mmio_read_raz, vgic_mmio_write_wi, 1),
>  	REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_ENABLE_SET,
> -- 
> 2.7.3
>