Re: qemu-kvm: event writeback can overwrite interrupts with -no-kvm-irqchip

[Jan Kiszka <jan.kiszka@siemens.com>]

Marcelo Tosatti wrote:
> Interrupts that are injected during a vcpu event save/writeback cycle
> are lost.
> 
> Fix by writebacking the state before injecting interrupts.

Good catch.

If that code were to stay, I would now suggest to move the injection
into pre_kvm_run instead, just like upstream does. But it I guess that
doesn't matters anymore.

Jan

> 
> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
> 
> diff --git a/qemu-kvm.c b/qemu-kvm.c
> index 91f0222..90ace20 100644
> --- a/qemu-kvm.c
> +++ b/qemu-kvm.c
> @@ -885,11 +885,6 @@ int pre_kvm_run(kvm_context_t kvm, CPUState *env)
>  {
>      kvm_arch_pre_run(env, env->kvm_run);
>  
> -    if (env->kvm_vcpu_dirty) {
> -        kvm_arch_load_regs(env, KVM_PUT_RUNTIME_STATE);
> -        env->kvm_vcpu_dirty = 0;
> -    }
> -
>      pthread_mutex_unlock(&qemu_mutex);
>      return 0;
>  }
> @@ -907,6 +902,10 @@ int kvm_run(CPUState *env)
>      int fd = env->kvm_fd;
>  
>    again:
> +    if (env->kvm_vcpu_dirty) {
> +        kvm_arch_load_regs(env, KVM_PUT_RUNTIME_STATE);
> +        env->kvm_vcpu_dirty = 0;
> +    }
>      push_nmi(kvm);
>  #if !defined(__s390__)
>      if (!kvm->irqchip_in_kernel)

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux