RISC-V: KVM: Expose APLIC registers as attributes of AIA irqchip

We expose APLIC registers as KVM device attributes of the in-kernel
AIA irqchip device. This will allow KVM user-space to save/restore
APLIC state using KVM device ioctls().

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Anup Patel <anup@brainfault.org>

arch/riscv/include/asm/kvm_aia.h

@@ -129,6 +129,9 @@ static inline void kvm_riscv_vcpu_aia_imsic_cleanup(struct kvm_vcpu *vcpu)
 {
 }
 
+int kvm_riscv_aia_aplic_set_attr(struct kvm *kvm, unsigned long type, u32 v);
+int kvm_riscv_aia_aplic_get_attr(struct kvm *kvm, unsigned long type, u32 *v);
+int kvm_riscv_aia_aplic_has_attr(struct kvm *kvm, unsigned long type);
 int kvm_riscv_aia_aplic_inject(struct kvm *kvm, u32 source, bool level);
 int kvm_riscv_aia_aplic_init(struct kvm *kvm);
 void kvm_riscv_aia_aplic_cleanup(struct kvm *kvm);

arch/riscv/include/uapi/asm/kvm.h

@@ -249,6 +249,12 @@ enum KVM_RISCV_SBI_EXT_ID {
 #define KVM_DEV_RISCV_AIA_GRP_CTRL		2
 #define KVM_DEV_RISCV_AIA_CTRL_INIT		0
 
+/*
+ * The device attribute type contains the memory mapped offset of the
+ * APLIC register (range 0x0000-0x3FFF) and it must be 4-byte aligned.
+ */
+#define KVM_DEV_RISCV_AIA_GRP_APLIC		3
+
 /* One single KVM irqchip, ie. the AIA */
 #define KVM_NR_IRQCHIPS			1
 

arch/riscv/kvm/aia_aplic.c

@@ -501,6 +501,49 @@ static struct kvm_io_device_ops aplic_iodoev_ops = {
 	.write = aplic_mmio_write,
 };
 
+int kvm_riscv_aia_aplic_set_attr(struct kvm *kvm, unsigned long type, u32 v)
+{
+	int rc;
+
+	if (!kvm->arch.aia.aplic_state)
+		return -ENODEV;
+
+	rc = aplic_mmio_write_offset(kvm, type, v);
+	if (rc)
+		return rc;
+
+	return 0;
+}
+
+int kvm_riscv_aia_aplic_get_attr(struct kvm *kvm, unsigned long type, u32 *v)
+{
+	int rc;
+
+	if (!kvm->arch.aia.aplic_state)
+		return -ENODEV;
+
+	rc = aplic_mmio_read_offset(kvm, type, v);
+	if (rc)
+		return rc;
+
+	return 0;
+}
+
+int kvm_riscv_aia_aplic_has_attr(struct kvm *kvm, unsigned long type)
+{
+	int rc;
+	u32 val;
+
+	if (!kvm->arch.aia.aplic_state)
+		return -ENODEV;
+
+	rc = aplic_mmio_read_offset(kvm, type, &val);
+	if (rc)
+		return rc;
+
+	return 0;
+}
+
 int kvm_riscv_aia_aplic_init(struct kvm *kvm)
 {
 	int i, ret = 0;

arch/riscv/kvm/aia_device.c

@@ -365,6 +365,15 @@ static int aia_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
 			break;
 		}
 
+		break;
+	case KVM_DEV_RISCV_AIA_GRP_APLIC:
+		if (copy_from_user(&nr, uaddr, sizeof(nr)))
+			return -EFAULT;
+
+		mutex_lock(&dev->kvm->lock);
+		r = kvm_riscv_aia_aplic_set_attr(dev->kvm, type, nr);
+		mutex_unlock(&dev->kvm->lock);
+
 		break;
 	}
 
@@ -412,6 +421,20 @@ static int aia_get_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
 		if (copy_to_user(uaddr, &addr, sizeof(addr)))
 			return -EFAULT;
 
+		break;
+	case KVM_DEV_RISCV_AIA_GRP_APLIC:
+		if (copy_from_user(&nr, uaddr, sizeof(nr)))
+			return -EFAULT;
+
+		mutex_lock(&dev->kvm->lock);
+		r = kvm_riscv_aia_aplic_get_attr(dev->kvm, type, &nr);
+		mutex_unlock(&dev->kvm->lock);
+		if (r)
+			return r;
+
+		if (copy_to_user(uaddr, &nr, sizeof(nr)))
+			return -EFAULT;
+
 		break;
 	}
 
@@ -448,6 +471,8 @@ static int aia_has_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
 			return 0;
 		}
 		break;
+	case KVM_DEV_RISCV_AIA_GRP_APLIC:
+		return kvm_riscv_aia_aplic_has_attr(dev->kvm, attr->attr);
 	}
 
 	return -ENXIO;