Re: [PATCH v3 2/5] hw/intc/loongarch_pch_pic: Fix bugs for update_irq function

[Richard Henderson <richard.henderson@linaro.org>]

On 7/15/22 11:37, Xiaojuan Yang wrote:
> Fix such errors:
> 1. We should not use 'unsigned long' type as argument when we use
> find_first_bit(), and we use ctz64() to replace find_first_bit()
> to fix this bug.
> 2. It is not standard to use '1ULL << irq' to generate a irq mask.
> So, we replace it with 'MAKE_64BIT_MASK(irq, 1)'.
> 
> Fix coverity CID: 1489761 1489764 1489765
> 
> Signed-off-by: Xiaojuan Yang <yangxiaojuan@loongson.cn>
> ---
>   hw/intc/loongarch_pch_pic.c | 18 +++++++++++-------
>   1 file changed, 11 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/intc/loongarch_pch_pic.c b/hw/intc/loongarch_pch_pic.c
> index 3c9814a3b4..8fa64d2030 100644
> --- a/hw/intc/loongarch_pch_pic.c
> +++ b/hw/intc/loongarch_pch_pic.c
> @@ -15,22 +15,26 @@
>   
>   static void pch_pic_update_irq(LoongArchPCHPIC *s, uint64_t mask, int level)
>   {
> -    unsigned long val;
> +    uint64_t val;
>       int irq;
>   
>       if (level) {
>           val = mask & s->intirr & ~s->int_mask;
>           if (val) {
> -            irq = find_first_bit(&val, 64);
> -            s->intisr |= 0x1ULL << irq;
> -            qemu_set_irq(s->parent_irq[s->htmsi_vector[irq]], 1);
> +            irq = ctz64(val);
> +            if (irq < 64) {

This test is always true, provable by the val != 0 test just above.


r~

> +                s->intisr |= MAKE_64BIT_MASK(irq, 1);
> +                qemu_set_irq(s->parent_irq[s->htmsi_vector[irq]], 1);
> +            }
>           }
>       } else {
>           val = mask & s->intisr;
>           if (val) {
> -            irq = find_first_bit(&val, 64);
> -            s->intisr &= ~(0x1ULL << irq);
> -            qemu_set_irq(s->parent_irq[s->htmsi_vector[irq]], 0);
> +            irq = ctz64(val);
> +            if (irq < 64) {
> +                s->intisr &= ~(MAKE_64BIT_MASK(irq, 1));
> +                qemu_set_irq(s->parent_irq[s->htmsi_vector[irq]], 0);
> +            }
>           }
>       }
>   }