[PATCH v3 47/55] KVM: arm/arm64: vgic-new: Add userland GIC CPU interface access

[christoffer.dall@linaro.org (Christoffer Dall)]

On Fri, May 06, 2016 at 11:46:00AM +0100, Andre Przywara wrote:
> Using the VMCR accessors we provide access to GIC CPU interface state
> to userland by wiring it up to the existing userland interface.
> [Marc: move and make VMCR accessors static, streamline MMIO handlers]

does this mean Marc did this and serves as credit or is it a lost
reminder?

> 
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
> Changelog v2 .. v3:
> - total rework, moving into vgic-mmio-v2.c
> - move vmcr accessor wrapper functions into this file
> - use the register description table for CPU i/f registers as well
> - add RAZ/WI handling for the active priority registers
> - streamline MMIO handler functions
> 
>  virt/kvm/arm/vgic/vgic-kvm-device.c |   2 +-
>  virt/kvm/arm/vgic/vgic-mmio-v2.c    | 104 ++++++++++++++++++++++++++++++++++++
>  virt/kvm/arm/vgic/vgic.h            |   2 +
>  3 files changed, 107 insertions(+), 1 deletion(-)
> 
> diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
> index bb33af8..2122ff2 100644
> --- a/virt/kvm/arm/vgic/vgic-kvm-device.c
> +++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
> @@ -300,7 +300,7 @@ static int vgic_attr_regs_access(struct kvm_device *dev,
>  
>  	switch (attr->group) {
>  	case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
> -		ret = -EINVAL;
> +		ret = vgic_v2_cpuif_uaccess(vcpu, is_write, addr, reg);
>  		break;
>  	case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
>  		ret = vgic_v2_dist_uaccess(vcpu, is_write, addr, reg);
> diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c
> index c453e6f..0060539 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio-v2.c
> +++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c
> @@ -206,6 +206,84 @@ static void vgic_mmio_write_sgipends(struct kvm_vcpu *vcpu,
>  	}
>  }
>  
> +static void vgic_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr)
> +{
> +	if (kvm_vgic_global_state.type == VGIC_V2)
> +		vgic_v2_set_vmcr(vcpu, vmcr);
> +	else
> +		vgic_v3_set_vmcr(vcpu, vmcr);
> +}
> +
> +static void vgic_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr)
> +{
> +	if (kvm_vgic_global_state.type == VGIC_V2)
> +		vgic_v2_get_vmcr(vcpu, vmcr);
> +	else
> +		vgic_v3_get_vmcr(vcpu, vmcr);
> +}
> +
> +#define GICC_ARCH_VERSION_V2	0x2
> +
> +/* These are for userland accesses only, there is no guest-facing emulation. */
> +static unsigned long vgic_mmio_read_vcpuif(struct kvm_vcpu *vcpu,
> +					   gpa_t addr, unsigned int len)
> +{
> +	struct vgic_vmcr vmcr;
> +	u32 val;
> +
> +	vgic_get_vmcr(vcpu, &vmcr);
> +
> +	switch (addr & 0xff) {
> +	case GIC_CPU_CTRL:
> +		val = vmcr.ctlr;
> +		break;
> +	case GIC_CPU_PRIMASK:
> +		val = vmcr.pmr;
> +		break;
> +	case GIC_CPU_BINPOINT:
> +		val = vmcr.bpr;
> +		break;
> +	case GIC_CPU_ALIAS_BINPOINT:
> +		val = vmcr.abpr;
> +		break;
> +	case GIC_CPU_IDENT:
> +		val = ((PRODUCT_ID_KVM << 20) |
> +		       (GICC_ARCH_VERSION_V2 << 16) |
> +		       IMPLEMENTER_ARM);
> +		break;
> +	default:
> +		return 0;
> +	}
> +
> +	return extract_bytes(val, addr & 3, len);

I don't think we allow anything than a full 32-bit aligned accesses
from userspace - we shouldn't at least.

> +}
> +
> +static void vgic_mmio_write_vcpuif(struct kvm_vcpu *vcpu,
> +				   gpa_t addr, unsigned int len,
> +				   unsigned long val)
> +{
> +	struct vgic_vmcr vmcr;
> +
> +	vgic_get_vmcr(vcpu, &vmcr);
> +
> +	switch (addr & 0xff) {
> +	case GIC_CPU_CTRL:
> +		vmcr.ctlr = val;
> +		break;
> +	case GIC_CPU_PRIMASK:
> +		vmcr.pmr = val;
> +		break;
> +	case GIC_CPU_BINPOINT:
> +		vmcr.bpr = val;
> +		break;
> +	case GIC_CPU_ALIAS_BINPOINT:
> +		vmcr.abpr = val;
> +		break;
> +	}
> +
> +	vgic_set_vmcr(vcpu, &vmcr);
> +}
> +
>  static const 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),
> @@ -237,6 +315,21 @@ static const struct vgic_register_region vgic_v2_dist_registers[] = {
>  		vgic_mmio_read_sgipend, vgic_mmio_write_sgipends, 16),
>  };
>  
> +static const struct vgic_register_region vgic_v2_cpu_registers[] = {
> +	REGISTER_DESC_WITH_LENGTH(GIC_CPU_CTRL,
> +		vgic_mmio_read_vcpuif, vgic_mmio_write_vcpuif, 4),
> +	REGISTER_DESC_WITH_LENGTH(GIC_CPU_PRIMASK,
> +		vgic_mmio_read_vcpuif, vgic_mmio_write_vcpuif, 4),
> +	REGISTER_DESC_WITH_LENGTH(GIC_CPU_BINPOINT,
> +		vgic_mmio_read_vcpuif, vgic_mmio_write_vcpuif, 4),
> +	REGISTER_DESC_WITH_LENGTH(GIC_CPU_ALIAS_BINPOINT,
> +		vgic_mmio_read_vcpuif, vgic_mmio_write_vcpuif, 4),
> +	REGISTER_DESC_WITH_LENGTH(GIC_CPU_ACTIVEPRIO,
> +		vgic_mmio_read_raz, vgic_mmio_write_wi, 16),
> +	REGISTER_DESC_WITH_LENGTH(GIC_CPU_IDENT,
> +		vgic_mmio_read_vcpuif, vgic_mmio_write_vcpuif, 4),
> +};
> +
>  unsigned int vgic_v2_init_dist_iodev(struct vgic_io_device *dev)
>  {
>  	dev->regions = vgic_v2_dist_registers;
> @@ -306,6 +399,17 @@ static int vgic_uaccess(struct kvm_vcpu *vcpu, struct vgic_io_device *dev,
>  	return ret;
>  }
>  
> +int vgic_v2_cpuif_uaccess(struct kvm_vcpu *vcpu, bool is_write,
> +			  int offset, u32 *val)
> +{
> +	struct vgic_io_device dev = {
> +		.regions = vgic_v2_cpu_registers,
> +		.nr_regions = ARRAY_SIZE(vgic_v2_cpu_registers),
> +	};
> +
> +	return vgic_uaccess(vcpu, &dev, is_write, offset, val);
> +}
> +
>  int vgic_v2_dist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
>  			 int offset, u32 *val)
>  {
> diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
> index 5260d23..7a69955 100644
> --- a/virt/kvm/arm/vgic/vgic.h
> +++ b/virt/kvm/arm/vgic/vgic.h
> @@ -39,6 +39,8 @@ void vgic_v2_set_underflow(struct kvm_vcpu *vcpu);
>  int vgic_v2_has_attr_regs(struct kvm_device *dev, struct kvm_device_attr *attr);
>  int vgic_v2_dist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
>  			 int offset, u32 *val);
> +int vgic_v2_cpuif_uaccess(struct kvm_vcpu *vcpu, bool is_write,
> +			  int offset, u32 *val);
>  void vgic_v2_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
>  void vgic_v2_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
>  int vgic_register_dist_iodev(struct kvm *kvm, gpa_t dist_base_address,
> -- 
> 2.7.3
> 

Thanks,
-Christoffer