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[PATCH 2/2] LoongArch: KVM:: simplify kvm_deliver_intr()

Yury Norov posted 2 patches 6 months, 3 weeks ago
[PATCH 2/2] LoongArch: KVM:: simplify kvm_deliver_intr()
Posted by Yury Norov 6 months, 3 weeks ago 
From: "Yury Norov (NVIDIA)" <yury.norov@gmail.com>

The function opencodes for_each_set_bit() macro, which makes it bulky.
Using the proper API makes all the housekeeping code going away.

Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
---
 arch/loongarch/kvm/interrupt.c | 25 ++++---------------------
 1 file changed, 4 insertions(+), 21 deletions(-)

diff --git a/arch/loongarch/kvm/interrupt.c b/arch/loongarch/kvm/interrupt.c
index 4c3f22de4b40..8462083f0301 100644
--- a/arch/loongarch/kvm/interrupt.c
+++ b/arch/loongarch/kvm/interrupt.c
@@ -83,28 +83,11 @@ void kvm_deliver_intr(struct kvm_vcpu *vcpu)
 	unsigned long *pending = &vcpu->arch.irq_pending;
 	unsigned long *pending_clr = &vcpu->arch.irq_clear;
 
-	if (!(*pending) && !(*pending_clr))
-		return;
-
-	if (*pending_clr) {
-		priority = __ffs(*pending_clr);
-		while (priority <= INT_IPI) {
-			kvm_irq_clear(vcpu, priority);
-			priority = find_next_bit(pending_clr,
-					BITS_PER_BYTE * sizeof(*pending_clr),
-					priority + 1);
-		}
-	}
+	for_each_set_bit(priority, pending_clr, INT_IPI + 1)
+		kvm_irq_clear(vcpu, priority);
 
-	if (*pending) {
-		priority = __ffs(*pending);
-		while (priority <= INT_IPI) {
-			kvm_irq_deliver(vcpu, priority);
-			priority = find_next_bit(pending,
-					BITS_PER_BYTE * sizeof(*pending),
-					priority + 1);
-		}
-	}
+	for_each_set_bit(priority, pending, INT_IPI + 1)
+		kvm_irq_deliver(vcpu, priority);
 }
 
 int kvm_pending_timer(struct kvm_vcpu *vcpu)
-- 
2.43.0
Re: [PATCH 2/2] LoongArch: KVM:: simplify kvm_deliver_intr()
Posted by Huacai Chen 6 months, 3 weeks ago 
Hi, Yury,

On Thu, Jul 17, 2025 at 12:59 AM Yury Norov <yury.norov@gmail.com> wrote:
>
> From: "Yury Norov (NVIDIA)" <yury.norov@gmail.com>
>
> The function opencodes for_each_set_bit() macro, which makes it bulky.
> Using the proper API makes all the housekeeping code going away.
>
> Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
> ---
>  arch/loongarch/kvm/interrupt.c | 25 ++++---------------------
>  1 file changed, 4 insertions(+), 21 deletions(-)
>
> diff --git a/arch/loongarch/kvm/interrupt.c b/arch/loongarch/kvm/interrupt.c
> index 4c3f22de4b40..8462083f0301 100644
> --- a/arch/loongarch/kvm/interrupt.c
> +++ b/arch/loongarch/kvm/interrupt.c
> @@ -83,28 +83,11 @@ void kvm_deliver_intr(struct kvm_vcpu *vcpu)
>         unsigned long *pending = &vcpu->arch.irq_pending;
>         unsigned long *pending_clr = &vcpu->arch.irq_clear;
>
> -       if (!(*pending) && !(*pending_clr))
> -               return;
Is it necessary to keep these two lines?

Huacai

> -
> -       if (*pending_clr) {
> -               priority = __ffs(*pending_clr);
> -               while (priority <= INT_IPI) {
> -                       kvm_irq_clear(vcpu, priority);
> -                       priority = find_next_bit(pending_clr,
> -                                       BITS_PER_BYTE * sizeof(*pending_clr),
> -                                       priority + 1);
> -               }
> -       }
> +       for_each_set_bit(priority, pending_clr, INT_IPI + 1)
> +               kvm_irq_clear(vcpu, priority);
>
> -       if (*pending) {
> -               priority = __ffs(*pending);
> -               while (priority <= INT_IPI) {
> -                       kvm_irq_deliver(vcpu, priority);
> -                       priority = find_next_bit(pending,
> -                                       BITS_PER_BYTE * sizeof(*pending),
> -                                       priority + 1);
> -               }
> -       }
> +       for_each_set_bit(priority, pending, INT_IPI + 1)
> +               kvm_irq_deliver(vcpu, priority);
>  }
>
>  int kvm_pending_timer(struct kvm_vcpu *vcpu)
> --
> 2.43.0
>
>
Re: [PATCH 2/2] LoongArch: KVM:: simplify kvm_deliver_intr()
Posted by Yury Norov 6 months, 3 weeks ago 
On Fri, Jul 18, 2025 at 12:13:46PM +0800, Huacai Chen wrote:
> Hi, Yury,
> 
> On Thu, Jul 17, 2025 at 12:59 AM Yury Norov <yury.norov@gmail.com> wrote:
> >
> > From: "Yury Norov (NVIDIA)" <yury.norov@gmail.com>
> >
> > The function opencodes for_each_set_bit() macro, which makes it bulky.
> > Using the proper API makes all the housekeeping code going away.
> >
> > Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
> > ---
> >  arch/loongarch/kvm/interrupt.c | 25 ++++---------------------
> >  1 file changed, 4 insertions(+), 21 deletions(-)
> >
> > diff --git a/arch/loongarch/kvm/interrupt.c b/arch/loongarch/kvm/interrupt.c
> > index 4c3f22de4b40..8462083f0301 100644
> > --- a/arch/loongarch/kvm/interrupt.c
> > +++ b/arch/loongarch/kvm/interrupt.c
> > @@ -83,28 +83,11 @@ void kvm_deliver_intr(struct kvm_vcpu *vcpu)
> >         unsigned long *pending = &vcpu->arch.irq_pending;
> >         unsigned long *pending_clr = &vcpu->arch.irq_clear;
> >
> > -       if (!(*pending) && !(*pending_clr))
> > -               return;
> Is it necessary to keep these two lines?

No. They duplicate the existing logic, and the new one based on
for_each_set_bit(). That's why I remove them.

Thanks,
Yury

> > -
> > -       if (*pending_clr) {
> > -               priority = __ffs(*pending_clr);
> > -               while (priority <= INT_IPI) {
> > -                       kvm_irq_clear(vcpu, priority);
> > -                       priority = find_next_bit(pending_clr,
> > -                                       BITS_PER_BYTE * sizeof(*pending_clr),
> > -                                       priority + 1);
> > -               }
> > -       }
> > +       for_each_set_bit(priority, pending_clr, INT_IPI + 1)
> > +               kvm_irq_clear(vcpu, priority);
> >
> > -       if (*pending) {
> > -               priority = __ffs(*pending);
> > -               while (priority <= INT_IPI) {
> > -                       kvm_irq_deliver(vcpu, priority);
> > -                       priority = find_next_bit(pending,
> > -                                       BITS_PER_BYTE * sizeof(*pending),
> > -                                       priority + 1);
> > -               }
> > -       }
> > +       for_each_set_bit(priority, pending, INT_IPI + 1)
> > +               kvm_irq_deliver(vcpu, priority);
> >  }
> >
> >  int kvm_pending_timer(struct kvm_vcpu *vcpu)
> > --
> > 2.43.0
> >
> >
Re: [PATCH 2/2] LoongArch: KVM:: simplify kvm_deliver_intr()
Posted by Bibo Mao 6 months, 3 weeks ago 

On 2025/7/17 上午12:59, Yury Norov wrote:
> From: "Yury Norov (NVIDIA)" <yury.norov@gmail.com>
> 
> The function opencodes for_each_set_bit() macro, which makes it bulky.
> Using the proper API makes all the housekeeping code going away.
> 
> Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
> ---
>   arch/loongarch/kvm/interrupt.c | 25 ++++---------------------
>   1 file changed, 4 insertions(+), 21 deletions(-)
> 
> diff --git a/arch/loongarch/kvm/interrupt.c b/arch/loongarch/kvm/interrupt.c
> index 4c3f22de4b40..8462083f0301 100644
> --- a/arch/loongarch/kvm/interrupt.c
> +++ b/arch/loongarch/kvm/interrupt.c
> @@ -83,28 +83,11 @@ void kvm_deliver_intr(struct kvm_vcpu *vcpu)
>   	unsigned long *pending = &vcpu->arch.irq_pending;
>   	unsigned long *pending_clr = &vcpu->arch.irq_clear;
>   
> -	if (!(*pending) && !(*pending_clr))
> -		return;
> -
> -	if (*pending_clr) {
> -		priority = __ffs(*pending_clr);
> -		while (priority <= INT_IPI) {
> -			kvm_irq_clear(vcpu, priority);
> -			priority = find_next_bit(pending_clr,
> -					BITS_PER_BYTE * sizeof(*pending_clr),
> -					priority + 1);
> -		}
> -	}
> +	for_each_set_bit(priority, pending_clr, INT_IPI + 1)
> +		kvm_irq_clear(vcpu, priority);
>   
> -	if (*pending) {
> -		priority = __ffs(*pending);
> -		while (priority <= INT_IPI) {
> -			kvm_irq_deliver(vcpu, priority);
> -			priority = find_next_bit(pending,
> -					BITS_PER_BYTE * sizeof(*pending),
> -					priority + 1);
> -		}
> -	}
> +	for_each_set_bit(priority, pending, INT_IPI + 1)
> +		kvm_irq_deliver(vcpu, priority);
>   }
>   
>   int kvm_pending_timer(struct kvm_vcpu *vcpu)
> 
Hi Yury,

Thanks for your patch. And it looks good to me.

Reviewed-by: Bibo Mao <maobibo@loongson.cn>

Regards
Bibo Mao

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