linux-kernel - Re: [PATCH v3 3/4] LongArch: KVM: Add irqfd set dintc msi

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Message-ID: <58ebb829-1edd-1c89-3947-a19e4e3cef17@loongson.cn>
Date: Mon, 8 Dec 2025 11:58:47 +0800
From: Bibo Mao <maobibo@...ngson.cn>
To: Song Gao <gaosong@...ngson.cn>, chenhuacai@...nel.org
Cc: kvm@...r.kernel.org, loongarch@...ts.linux.dev, kernel@...0n.name,
 linux-kernel@...r.kernel.org, lixianglai@...ngson.cn
Subject: Re: [PATCH v3 3/4] LongArch: KVM: Add irqfd set dintc msi



On 2025/12/6 下午2:46, Song Gao wrote:
> Add irqfd choice dintc to set msi irq by the msg_addr and
> implement dintc set msi irq.
> 
> Signed-off-by: Song Gao <gaosong@...ngson.cn>
> ---
>   arch/loongarch/include/asm/kvm_dintc.h |  1 +
>   arch/loongarch/kvm/intc/dintc.c        |  6 ++++
>   arch/loongarch/kvm/irqfd.c             | 45 ++++++++++++++++++++++----
>   3 files changed, 45 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/loongarch/include/asm/kvm_dintc.h b/arch/loongarch/include/asm/kvm_dintc.h
> index d980d39c0344..f87fb802a7bf 100644
> --- a/arch/loongarch/include/asm/kvm_dintc.h
> +++ b/arch/loongarch/include/asm/kvm_dintc.h
> @@ -11,6 +11,7 @@ struct loongarch_dintc  {
>   	struct kvm *kvm;
>   	uint64_t msg_addr_base;
>   	uint64_t msg_addr_size;
> +	uint32_t cpu_mask;
>   };
>   
>   struct dintc_state {
> diff --git a/arch/loongarch/kvm/intc/dintc.c b/arch/loongarch/kvm/intc/dintc.c
> index cd6cc9392adc..15e2ccd25a63 100644
> --- a/arch/loongarch/kvm/intc/dintc.c
> +++ b/arch/loongarch/kvm/intc/dintc.c
> @@ -15,6 +15,7 @@ static int kvm_dintc_ctrl_access(struct kvm_device *dev,
>   	void __user *data;
>   	struct loongarch_dintc *s = dev->kvm->arch.dintc;
>   	u64 tmp;
> +	u32 cpu_bit;
>   
>   	data = (void __user *)attr->addr;
>   	switch (addr) {
> @@ -30,6 +31,11 @@ static int kvm_dintc_ctrl_access(struct kvm_device *dev,
>   				s->msg_addr_base = tmp;
>   			else
>   				return  -EFAULT;
> +			s->msg_addr_base = tmp;
> +			cpu_bit = find_first_bit((unsigned long *)&(s->msg_addr_base), 64)
> +						- AVEC_CPU_SHIFT;
> +			cpu_bit = min(cpu_bit, AVEC_CPU_BIT);
> +			s->cpu_mask = GENMASK(cpu_bit - 1, 0) & AVEC_CPU_MASK;
>   		}
>   		break;
>   	case KVM_DEV_LOONGARCH_DINTC_MSG_ADDR_SIZE:
> diff --git a/arch/loongarch/kvm/irqfd.c b/arch/loongarch/kvm/irqfd.c
> index 9a39627aecf0..d49a6c6471df 100644
> --- a/arch/loongarch/kvm/irqfd.c
> +++ b/arch/loongarch/kvm/irqfd.c
> @@ -6,6 +6,7 @@
>   #include <linux/kvm_host.h>
>   #include <trace/events/kvm.h>
>   #include <asm/kvm_pch_pic.h>
> +#include <asm/kvm_vcpu.h>
>   
>   static int kvm_set_pic_irq(struct kvm_kernel_irq_routing_entry *e,
>   		struct kvm *kvm, int irq_source_id, int level, bool line_status)
> @@ -16,6 +17,41 @@ static int kvm_set_pic_irq(struct kvm_kernel_irq_routing_entry *e,
>   	return 0;
>   }
>   
> +static int kvm_dintc_set_msi_irq(struct kvm *kvm, u32 addr, int data, int level)
> +{
> +	unsigned int virq, dest;
> +	struct kvm_vcpu *vcpu;
> +
> +	virq = (addr >> AVEC_VIRQ_SHIFT) & AVEC_VIRQ_MASK;
> +	dest = (addr >> AVEC_CPU_SHIFT) & kvm->arch.dintc->cpu_mask;
> +	if (dest > KVM_MAX_VCPUS)
> +		return -EINVAL;
> +	vcpu = kvm_get_vcpu_by_cpuid(kvm, dest);
> +	if (!vcpu)
> +		return -EINVAL;
> +	return kvm_loongarch_deliver_msi_to_vcpu(kvm, vcpu, virq, level);
> +}
> +
> +static int loongarch_set_msi(struct kvm_kernel_irq_routing_entry *e,
> +			struct kvm *kvm, int level)
> +{
> +	u64 msg_addr;
> +
> +	if (!level)
> +		return -1;
> +
> +	msg_addr = (((u64)e->msi.address_hi) << 32) | e->msi.address_lo;
> +	if (cpu_has_msgint && kvm->arch.dintc &&
> +		msg_addr >= kvm->arch.dintc->msg_addr_base &&
> +		msg_addr < (kvm->arch.dintc->msg_addr_base  + kvm->arch.dintc->msg_addr_size)) {
> +		return kvm_dintc_set_msi_irq(kvm, msg_addr, e->msi.data, level);
> +	} else {
> +		pch_msi_set_irq(kvm, e->msi.data, level);
> +	}
> +
> +	return 0;
> +}
> +
>   /*
>    * kvm_set_msi: inject the MSI corresponding to the
>    * MSI routing entry
> @@ -26,12 +62,7 @@ static int kvm_set_pic_irq(struct kvm_kernel_irq_routing_entry *e,
>   int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
>   		struct kvm *kvm, int irq_source_id, int level, bool line_status)
>   {
> -	if (!level)
> -		return -1;
> -
> -	pch_msi_set_irq(kvm, e->msi.data, level);
> -
> -	return 0;
> +	return loongarch_set_msi(e, kvm, level);
>   }
>   
>   /*
> @@ -76,7 +107,7 @@ int kvm_arch_set_irq_inatomic(struct kvm_kernel_irq_routing_entry *e,
>   		pch_pic_set_irq(kvm->arch.pch_pic, e->irqchip.pin, level);
>   		return 0;
>   	case KVM_IRQ_ROUTING_MSI:
> -		pch_msi_set_irq(kvm, e->msi.data, level);
> +		loongarch_set_msi(e, kvm, level);
>   		return 0;
>   	default:
>   		return -EWOULDBLOCK;
> 
Reviewed-by: Bibo Mao <maobibo@...ngson.cn>