Re: [RFC 32/55] KVM: arm/arm64: register GICH iodev for the guest hypervisor

[Christoffer Dall]

On Mon, Jan 09, 2017 at 01:24:28AM -0500, Jintack Lim wrote:
> Register a device for the virtual interface control block(GICH) access
> from the guest hypervisor.
> 
> TODO: Get GICH address from DT, which is hardcoded now.
> 

It's not so much about the DT as it is adding an API for userspace to
tell KVM where to place it, and userspace can add the same required info
into the DT/ACPI as needed.

This is obviously something we have to address sooner as opposed to
later.

Thanks,
-Christoffer

> Signed-off-by: Jintack Lim <jintack@xxxxxxxxxxxxxxx>
> ---
>  arch/arm64/include/uapi/asm/kvm.h  |  6 ++++++
>  include/kvm/arm_vgic.h             |  5 ++++-
>  virt/kvm/arm/vgic/vgic-mmio.c      |  6 ++++++
>  virt/kvm/arm/vgic/vgic-v2-nested.c | 24 ++++++++++++++++++++++++
>  virt/kvm/arm/vgic/vgic-v2.c        |  7 +++++++
>  virt/kvm/arm/vgic/vgic.h           |  6 ++++++
>  6 files changed, 53 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
> index 78117bf..3995d3d 100644
> --- a/arch/arm64/include/uapi/asm/kvm.h
> +++ b/arch/arm64/include/uapi/asm/kvm.h
> @@ -99,6 +99,12 @@ struct kvm_regs {
>  #define KVM_ARM_VCPU_PMU_V3		3 /* Support guest PMUv3 */
>  #define KVM_ARM_VCPU_NESTED_VIRT	4 /* Support nested virtual EL2 */
>  
> +/* FIXME: This should come from DT */
> +#ifdef CONFIG_KVM_ARM_NESTED_HYP
> +#define KVM_VGIC_V2_GICH_BASE          0x08030000
> +#define KVM_VGIC_V2_GICH_SIZE          0x2000
> +#endif
> +
>  struct kvm_vcpu_init {
>  	__u32 target;
>  	__u32 features[7];
> diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
> index fc882d6..5bda20c 100644
> --- a/include/kvm/arm_vgic.h
> +++ b/include/kvm/arm_vgic.h
> @@ -125,7 +125,8 @@ enum iodev_type {
>  	IODEV_CPUIF,
>  	IODEV_DIST,
>  	IODEV_REDIST,
> -	IODEV_ITS
> +	IODEV_ITS,
> +	IODEV_GICH,
>  };
>  
>  struct vgic_io_device {
> @@ -198,6 +199,8 @@ struct vgic_dist {
>  
>  	struct vgic_io_device	dist_iodev;
>  
> +	struct vgic_io_device	hyp_iodev;
> +
>  	bool			has_its;
>  
>  	/*
> diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
> index 049c570..2e4097d 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio.c
> +++ b/virt/kvm/arm/vgic/vgic-mmio.c
> @@ -512,6 +512,9 @@ static int dispatch_mmio_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
>  	case IODEV_ITS:
>  		data = region->its_read(vcpu->kvm, iodev->its, addr, len);
>  		break;
> +	case IODEV_GICH:
> +		data = region->read(vcpu, addr, len);
> +		break;
>  	}
>  
>  	vgic_data_host_to_mmio_bus(val, len, data);
> @@ -543,6 +546,9 @@ static int dispatch_mmio_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
>  	case IODEV_ITS:
>  		region->its_write(vcpu->kvm, iodev->its, addr, len, data);
>  		break;
> +	case IODEV_GICH:
> +		region->write(vcpu, addr, len, data);
> +		break;
>  	}
>  
>  	return 0;
> diff --git a/virt/kvm/arm/vgic/vgic-v2-nested.c b/virt/kvm/arm/vgic/vgic-v2-nested.c
> index 85f646b..cb55324 100644
> --- a/virt/kvm/arm/vgic/vgic-v2-nested.c
> +++ b/virt/kvm/arm/vgic/vgic-v2-nested.c
> @@ -206,6 +206,30 @@ static void vgic_mmio_write_v2_gich(struct kvm_vcpu *vcpu,
>  		4 * VGIC_V2_MAX_LRS, VGIC_ACCESS_32bit),
>  };
>  
> +int vgic_register_gich_iodev(struct kvm *kvm, struct vgic_dist *dist)
> +{
> +	struct vgic_io_device *io_device = &kvm->arch.vgic.hyp_iodev;
> +	int ret = 0;
> +	unsigned int len;
> +
> +	len = KVM_VGIC_V2_GICH_SIZE;
> +
> +	io_device->regions = vgic_v2_gich_registers;
> +	io_device->nr_regions = ARRAY_SIZE(vgic_v2_gich_registers);
> +	kvm_iodevice_init(&io_device->dev, &kvm_io_gic_ops);
> +
> +	io_device->base_addr = KVM_VGIC_V2_GICH_BASE;
> +	io_device->iodev_type = IODEV_GICH;
> +	io_device->redist_vcpu = NULL;
> +
> +	mutex_lock(&kvm->slots_lock);
> +	ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, KVM_VGIC_V2_GICH_BASE,
> +			len, &io_device->dev);
> +	mutex_unlock(&kvm->slots_lock);
> +
> +	return ret;
> +}
> +
>  /*
>   * For LRs which have HW bit set such as timer interrupts, we modify them to
>   * have the host hardware interrupt number instead of the virtual one programmed
> diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c
> index 9bab867..b8b73fd 100644
> --- a/virt/kvm/arm/vgic/vgic-v2.c
> +++ b/virt/kvm/arm/vgic/vgic-v2.c
> @@ -280,6 +280,13 @@ int vgic_v2_map_resources(struct kvm *kvm)
>  		goto out;
>  	}
>  
> +	/* Register virtual GICH interface to kvm io bus */
> +	ret = vgic_register_gich_iodev(kvm, dist);
> +	if (ret) {
> +		kvm_err("Unable to register VGIC GICH regions\n");
> +		goto out;
> +	}
> +
>  	if (!static_branch_unlikely(&vgic_v2_cpuif_trap)) {
>  		ret = kvm_phys_addr_ioremap(kvm, dist->vgic_cpu_base,
>  					    kvm_vgic_global_state.vcpu_base,
> diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
> index 2aef680..11d61a7 100644
> --- a/virt/kvm/arm/vgic/vgic.h
> +++ b/virt/kvm/arm/vgic/vgic.h
> @@ -121,8 +121,14 @@ static inline int vgic_its_inject_msi(struct kvm *kvm, struct kvm_msi *msi)
>  int vgic_init(struct kvm *kvm);
>  
>  #ifdef CONFIG_KVM_ARM_NESTED_HYP
> +int vgic_register_gich_iodev(struct kvm *kvm, struct vgic_dist *dist);
>  void vgic_init_nested(struct kvm_vcpu *vcpu);
>  #else
> +static inline int vgic_register_gich_iodev(struct kvm *kvm,
> +		struct vgic_dist *dist)
> +{
> +	return 0;
> +}
>  static inline void vgic_init_nested(struct kvm_vcpu *vcpu)
>  {
>  	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
> -- 
> 1.9.1
> 
>