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

From: [email-masked] (Andre Przywara)
Date: Wed, 11 May 2016 09:24:45 +0100

Hi,

On 09/05/16 18:27, Marc Zyngier wrote:
> On 06/05/16 11:46, 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]
>>
>> Signed-off-by: Andre Przywara <[email-masked]>
>> Signed-off-by: Marc Zyngier <[email-masked]>
>> ---
>> 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);
>> +}
>> +
>> +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)
>>  {
> 
> And what about this:
> 
> +int vgic_v2_has_attr_regs(struct kvm_device *dev, struct kvm_device_attr *attr)
> +{
> +       int nr_irqs = dev->kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS;
> +       const struct vgic_register_region *regions;
> +       gpa_t addr;
> +       int nr_regions, i, len;
> +
> +       addr = attr->attr & KVM_DEV_ARM_VGIC_OFFSET_MASK;
> +
> +       switch (attr->group) {
> +       case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
> +               regions = vgic_v2_dist_registers;
> +               nr_regions = ARRAY_SIZE(vgic_v2_dist_registers);
> +               break;
> +       case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
> +               return -ENXIO;          /* TODO: describe CPU i/f regs also */
> +       default:
> +               return -ENXIO;
> +       }
> 
> This TODO was already in the previous version. Can you please wire it
> and give save/restore a chance to work?

Oh dear, thanks for spotting this. It _was_ in my fix patch, but got
lost during the rebase. Will fix it.

Cheers,
Andre.