Re: [PATCH v3 2/4] LongArch: KVM: Add DINTC device support

[Bibo Mao <maobibo@loongson.cn>]

On 2025/12/6 下午2:46, Song Gao wrote:
> Add device model for AVEC interrupt controller, implement basic
> create/destroy/set_attr interfaces, and register device model to kvm
> device table.
> 
> Signed-off-by: Song Gao <gaosong@loongson.cn>
> ---
>   arch/loongarch/include/asm/kvm_dintc.h |  21 +++++
>   arch/loongarch/include/asm/kvm_host.h  |   3 +
>   arch/loongarch/include/uapi/asm/kvm.h  |   4 +
>   arch/loongarch/kvm/Makefile            |   1 +
>   arch/loongarch/kvm/intc/dintc.c        | 110 +++++++++++++++++++++++++
>   arch/loongarch/kvm/main.c              |   5 ++
>   include/uapi/linux/kvm.h               |   2 +
>   7 files changed, 146 insertions(+)
>   create mode 100644 arch/loongarch/include/asm/kvm_dintc.h
>   create mode 100644 arch/loongarch/kvm/intc/dintc.c
> 
> diff --git a/arch/loongarch/include/asm/kvm_dintc.h b/arch/loongarch/include/asm/kvm_dintc.h
> new file mode 100644
> index 000000000000..d980d39c0344
> --- /dev/null
> +++ b/arch/loongarch/include/asm/kvm_dintc.h
> @@ -0,0 +1,21 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2025 Loongson Technology Corporation Limited
> + */
> +
> +#ifndef __ASM_KVM_DINTC_H
> +#define __ASM_KVM_DINTC_H
> +
> +
> +struct loongarch_dintc  {
> +	struct kvm *kvm;
> +	uint64_t msg_addr_base;
> +	uint64_t msg_addr_size;
> +};
> +
> +struct dintc_state {
> +	atomic64_t  vector_map[4];
> +};
> +
> +int kvm_loongarch_register_dintc_device(void);
> +#endif
> diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include/asm/kvm_host.h
> index e4fe5b8e8149..26a90f4146ac 100644
> --- a/arch/loongarch/include/asm/kvm_host.h
> +++ b/arch/loongarch/include/asm/kvm_host.h
> @@ -22,6 +22,7 @@
>   #include <asm/kvm_ipi.h>
>   #include <asm/kvm_eiointc.h>
>   #include <asm/kvm_pch_pic.h>
> +#include <asm/kvm_dintc.h>
>   #include <asm/loongarch.h>
>   
>   #define __KVM_HAVE_ARCH_INTC_INITIALIZED
> @@ -134,6 +135,7 @@ struct kvm_arch {
>   	struct loongarch_ipi *ipi;
>   	struct loongarch_eiointc *eiointc;
>   	struct loongarch_pch_pic *pch_pic;
> +	struct loongarch_dintc *dintc;
>   };
>   
>   #define CSR_MAX_NUMS		0x800
> @@ -244,6 +246,7 @@ struct kvm_vcpu_arch {
>   	struct kvm_mp_state mp_state;
>   	/* ipi state */
>   	struct ipi_state ipi_state;
> +	struct dintc_state dintc_state;
>   	/* cpucfg */
>   	u32 cpucfg[KVM_MAX_CPUCFG_REGS];
>   
> diff --git a/arch/loongarch/include/uapi/asm/kvm.h b/arch/loongarch/include/uapi/asm/kvm.h
> index de6c3f18e40a..07da84f7002c 100644
> --- a/arch/loongarch/include/uapi/asm/kvm.h
> +++ b/arch/loongarch/include/uapi/asm/kvm.h
> @@ -154,4 +154,8 @@ struct kvm_iocsr_entry {
>   #define KVM_DEV_LOONGARCH_PCH_PIC_GRP_CTRL	        0x40000006
>   #define KVM_DEV_LOONGARCH_PCH_PIC_CTRL_INIT	        0
>   
> +#define KVM_DEV_LOONGARCH_DINTC_CTRL			0x40000007
> +#define KVM_DEV_LOONGARCH_DINTC_MSG_ADDR_BASE		0x0
> +#define KVM_DEV_LOONGARCH_DINTC_MSG_ADDR_SIZE		0x1
> +
>   #endif /* __UAPI_ASM_LOONGARCH_KVM_H */
> diff --git a/arch/loongarch/kvm/Makefile b/arch/loongarch/kvm/Makefile
> index cb41d9265662..fe984bf1cbdb 100644
> --- a/arch/loongarch/kvm/Makefile
> +++ b/arch/loongarch/kvm/Makefile
> @@ -19,6 +19,7 @@ kvm-y += vm.o
>   kvm-y += intc/ipi.o
>   kvm-y += intc/eiointc.o
>   kvm-y += intc/pch_pic.o
> +kvm-y += intc/dintc.o
>   kvm-y += irqfd.o
>   
>   CFLAGS_exit.o	+= $(call cc-disable-warning, override-init)
> diff --git a/arch/loongarch/kvm/intc/dintc.c b/arch/loongarch/kvm/intc/dintc.c
> new file mode 100644
> index 000000000000..cd6cc9392adc
> --- /dev/null
> +++ b/arch/loongarch/kvm/intc/dintc.c
> @@ -0,0 +1,110 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2025 Loongson Technology Corporation Limited
> + */
> +
> +#include <linux/kvm_host.h>
> +#include <asm/kvm_dintc.h>
> +#include <asm/kvm_vcpu.h>
> +
> +static int kvm_dintc_ctrl_access(struct kvm_device *dev,
> +				struct kvm_device_attr *attr,
> +				bool is_write)
> +{
> +	int addr = attr->attr;
> +	void __user *data;
> +	struct loongarch_dintc *s = dev->kvm->arch.dintc;
> +	u64 tmp;
> +
> +	data = (void __user *)attr->addr;
> +	switch (addr) {
> +	case KVM_DEV_LOONGARCH_DINTC_MSG_ADDR_BASE:
> +		if (is_write) {
> +			if (copy_from_user(&tmp, data, sizeof(s->msg_addr_base)))
> +				return -EFAULT;
> +			if (s->msg_addr_base) {
> +				/* Duplicate setting are not allowed. */
> +				return -EFAULT;
> +			}
> +			if (tmp > (1UL << AVEC_CPU_SHIFT))
The address check should be (tmp & (BIT(AVEC_CPU_SHIFT) - 1) == 0 ?
otherwise look good to me.

Reviewed-by: Bibo Mao <maobibo@loongson.cn>
> +				s->msg_addr_base = tmp;
> +			else
> +				return  -EFAULT;
> +		}
> +		break;
> +	case KVM_DEV_LOONGARCH_DINTC_MSG_ADDR_SIZE:
> +		if (is_write) {
> +			if (copy_from_user(&tmp, data, sizeof(s->msg_addr_size)))
> +				return -EFAULT;
> +			if (s->msg_addr_size) {
> +				/*Duplicate setting are not allowed. */
> +				return -EFAULT;
> +			}
> +			s->msg_addr_size = tmp;
> +		}
> +		break;
> +	default:
> +		kvm_err("%s: unknown dintc register, addr = %d\n", __func__, addr);
> +		return -ENXIO;
> +	}
> +
> +	return 0;
> +}
> +
> +static int kvm_dintc_set_attr(struct kvm_device *dev,
> +			struct kvm_device_attr *attr)
> +{
> +	switch (attr->group) {
> +	case KVM_DEV_LOONGARCH_DINTC_CTRL:
> +		return kvm_dintc_ctrl_access(dev, attr, true);
> +	default:
> +		kvm_err("%s: unknown group (%d)\n", __func__, attr->group);
> +		return -EINVAL;
> +	}
> +}
> +
> +static int kvm_dintc_create(struct kvm_device *dev, u32 type)
> +{
> +	struct kvm *kvm;
> +	struct loongarch_dintc *s;
> +
> +	if (!dev) {
> +		kvm_err("%s: kvm_device ptr is invalid!\n", __func__);
> +		return -EINVAL;
> +	}
> +
> +	kvm = dev->kvm;
> +	if (kvm->arch.dintc) {
> +		kvm_err("%s: LoongArch DINTC has already been created!\n", __func__);
> +		return -EINVAL;
> +	}
> +
> +	s = kzalloc(sizeof(struct loongarch_dintc), GFP_KERNEL);
> +	if (!s)
> +		return -ENOMEM;
> +
> +	s->kvm = kvm;
> +	kvm->arch.dintc = s;
> +	return 0;
> +}
> +
> +static void kvm_dintc_destroy(struct kvm_device *dev)
> +{
> +
> +	if (!dev || !dev->kvm || !dev->kvm->arch.dintc)
> +		return;
> +
> +	kfree(dev->kvm->arch.dintc);
> +}
> +
> +static struct kvm_device_ops kvm_dintc_dev_ops = {
> +	.name = "kvm-loongarch-dintc",
> +	.create = kvm_dintc_create,
> +	.destroy = kvm_dintc_destroy,
> +	.set_attr = kvm_dintc_set_attr,
> +};
> +
> +int kvm_loongarch_register_dintc_device(void)
> +{
> +	return kvm_register_device_ops(&kvm_dintc_dev_ops, KVM_DEV_TYPE_LOONGARCH_DINTC);
> +}
> diff --git a/arch/loongarch/kvm/main.c b/arch/loongarch/kvm/main.c
> index 80ea63d465b8..d18d9f4d485c 100644
> --- a/arch/loongarch/kvm/main.c
> +++ b/arch/loongarch/kvm/main.c
> @@ -408,6 +408,11 @@ static int kvm_loongarch_env_init(void)
>   
>   	/* Register LoongArch PCH-PIC interrupt controller interface. */
>   	ret = kvm_loongarch_register_pch_pic_device();
> +	if (ret)
> +		return ret;
> +
> +	/* Register LoongArch DINTC interrupt contrroller interface */
> +	ret = kvm_loongarch_register_dintc_device();
>   
>   	return ret;
>   }
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index dddb781b0507..ebf86a65eef1 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -1209,6 +1209,8 @@ enum kvm_device_type {
>   #define KVM_DEV_TYPE_LOONGARCH_EIOINTC	KVM_DEV_TYPE_LOONGARCH_EIOINTC
>   	KVM_DEV_TYPE_LOONGARCH_PCHPIC,
>   #define KVM_DEV_TYPE_LOONGARCH_PCHPIC	KVM_DEV_TYPE_LOONGARCH_PCHPIC
> +	KVM_DEV_TYPE_LOONGARCH_DINTC,
> +#define KVM_DEV_TYPE_LOONGARCH_DINTC   KVM_DEV_TYPE_LOONGARCH_DINTC
>   
>   	KVM_DEV_TYPE_MAX,
>   
>