Re: [PATCH v2 07/12] target/riscv: Support setting external interrupt by KVM

[Anup Patel <anup@xxxxxxxxxxxxxx>]

On Fri, Dec 10, 2021 at 3:37 PM Yifei Jiang <jiangyifei@xxxxxxxxxx> wrote:
>
> When KVM is enabled, set the S-mode external interrupt through
> kvm_riscv_set_irq function.
>
> Signed-off-by: Yifei Jiang <jiangyifei@xxxxxxxxxx>
> Signed-off-by: Mingwang Li <limingwang@xxxxxxxxxx>
> Reviewed-by: Alistair Francis <alistair.francis@xxxxxxx>
> ---
>  target/riscv/cpu.c       |  6 +++++-
>  target/riscv/kvm-stub.c  |  5 +++++
>  target/riscv/kvm.c       | 17 +++++++++++++++++
>  target/riscv/kvm_riscv.h |  1 +
>  4 files changed, 28 insertions(+), 1 deletion(-)
>
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index 1c944872a3..71a7ac6831 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -603,7 +603,11 @@ static void riscv_cpu_set_irq(void *opaque, int irq, int level)
>      case IRQ_S_EXT:
>      case IRQ_VS_EXT:
>      case IRQ_M_EXT:
> -        riscv_cpu_update_mip(cpu, 1 << irq, BOOL_TO_MASK(level));
> +        if (kvm_enabled() && (irq & IRQ_M_EXT) ) {
> +            kvm_riscv_set_irq(cpu, IRQ_S_EXT, level);
> +        } else {
> +            riscv_cpu_update_mip(cpu, 1 << irq, BOOL_TO_MASK(level));
> +        }

This does not look right.

I suggest the following:

if (kvm_enabled()) {
    kvm_riscv_set_irq(cpu, irq, level);
} else {
   riscv_cpu_update_mip(cpu, 1 << irq, BOOL_TO_MASK(level));
}

>          break;
>      default:
>          g_assert_not_reached();
> diff --git a/target/riscv/kvm-stub.c b/target/riscv/kvm-stub.c
> index 39b96fe3f4..4e8fc31a21 100644
> --- a/target/riscv/kvm-stub.c
> +++ b/target/riscv/kvm-stub.c
> @@ -23,3 +23,8 @@ void kvm_riscv_reset_vcpu(RISCVCPU *cpu)
>  {
>      abort();
>  }
> +
> +void kvm_riscv_set_irq(RISCVCPU *cpu, int irq, int level)
> +{
> +    abort();
> +}
> diff --git a/target/riscv/kvm.c b/target/riscv/kvm.c
> index db6d8a5b6e..0027f11f45 100644
> --- a/target/riscv/kvm.c
> +++ b/target/riscv/kvm.c
> @@ -383,6 +383,23 @@ void kvm_riscv_reset_vcpu(RISCVCPU *cpu)
>      env->satp = 0;
>  }
>
> +void kvm_riscv_set_irq(RISCVCPU *cpu, int irq, int level)
> +{
> +    int ret;
> +    unsigned virq = level ? KVM_INTERRUPT_SET : KVM_INTERRUPT_UNSET;
> +
> +    if (irq != IRQ_S_EXT) {
> +        perror("kvm riscv set irq != IRQ_S_EXT\n");
> +        abort();
> +    }
> +
> +    ret = kvm_vcpu_ioctl(CPU(cpu), KVM_INTERRUPT, &virq);
> +    if (ret < 0) {
> +        perror("Set irq failed");
> +        abort();
> +    }
> +}
> +
>  bool kvm_arch_cpu_check_are_resettable(void)
>  {
>      return true;
> diff --git a/target/riscv/kvm_riscv.h b/target/riscv/kvm_riscv.h
> index f38c82bf59..ed281bdce0 100644
> --- a/target/riscv/kvm_riscv.h
> +++ b/target/riscv/kvm_riscv.h
> @@ -20,5 +20,6 @@
>  #define QEMU_KVM_RISCV_H
>
>  void kvm_riscv_reset_vcpu(RISCVCPU *cpu);
> +void kvm_riscv_set_irq(RISCVCPU *cpu, int irq, int level);
>
>  #endif
> --
> 2.19.1
>

Regards,
Anup