KVM: arm/arm64: vgic-new: Add userland GIC CPU interface access

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 <andre.przywara@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>

virt/kvm/arm/vgic/vgic-kvm-device.c

@@ -274,7 +274,7 @@ 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);

virt/kvm/arm/vgic/vgic-mmio-v2.c

@@ -204,6 +204,84 @@ 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 val;
+}
+
+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,
@@ -249,6 +327,27 @@ static const struct vgic_register_region vgic_v2_dist_registers[] = {
 		VGIC_ACCESS_32bit | VGIC_ACCESS_8bit),
 };
 
+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,
+		VGIC_ACCESS_32bit),
+	REGISTER_DESC_WITH_LENGTH(GIC_CPU_PRIMASK,
+		vgic_mmio_read_vcpuif, vgic_mmio_write_vcpuif, 4,
+		VGIC_ACCESS_32bit),
+	REGISTER_DESC_WITH_LENGTH(GIC_CPU_BINPOINT,
+		vgic_mmio_read_vcpuif, vgic_mmio_write_vcpuif, 4,
+		VGIC_ACCESS_32bit),
+	REGISTER_DESC_WITH_LENGTH(GIC_CPU_ALIAS_BINPOINT,
+		vgic_mmio_read_vcpuif, vgic_mmio_write_vcpuif, 4,
+		VGIC_ACCESS_32bit),
+	REGISTER_DESC_WITH_LENGTH(GIC_CPU_ACTIVEPRIO,
+		vgic_mmio_read_raz, vgic_mmio_write_wi, 16,
+		VGIC_ACCESS_32bit),
+	REGISTER_DESC_WITH_LENGTH(GIC_CPU_IDENT,
+		vgic_mmio_read_vcpuif, vgic_mmio_write_vcpuif, 4,
+		VGIC_ACCESS_32bit),
+};
+
 unsigned int vgic_v2_init_dist_iodev(struct vgic_io_device *dev)
 {
 	dev->regions = vgic_v2_dist_registers;
@@ -274,7 +373,9 @@ int vgic_v2_has_attr_regs(struct kvm_device *dev, struct kvm_device_attr *attr)
 		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 */
+		regions = vgic_v2_cpu_registers;
+		nr_regions = ARRAY_SIZE(vgic_v2_cpu_registers);
+		break;
 	default:
 		return -ENXIO;
 	}
@@ -322,6 +423,17 @@ 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)
 {

virt/kvm/arm/vgic/vgic.h

@@ -47,6 +47,8 @@ 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,