[Qemu-devel] Re: [PATCH 12/22] kvm: Call qemu_kvm_eat_signals also under !CONFIG_IOTHREAD

[Marcelo Tosatti]

On Thu, Jan 27, 2011 at 02:09:56PM +0100, Jan Kiszka wrote:
> Move qemu_kvm_eat_signals around and call it also when the IO-thread is
> not used. Do not yet process SIGBUS, will be armed in a separate step.
> 
> Signed-off-by: Jan Kiszka <address@hidden>
> ---
>  cpus.c |   88 ++++++++++++++++++++++++++++++++++++---------------------------
>  1 files changed, 50 insertions(+), 38 deletions(-)
> 
> diff --git a/cpus.c b/cpus.c
> index 9071848..558c0d3 100644
> --- a/cpus.c
> +++ b/cpus.c
> @@ -261,6 +261,45 @@ static void qemu_kvm_init_cpu_signals(CPUState *env)
>      }
>  }
>  
> +static void qemu_kvm_eat_signals(CPUState *env)
> +{
> +    struct timespec ts = { 0, 0 };
> +    siginfo_t siginfo;
> +    sigset_t waitset;
> +    sigset_t chkset;
> +    int r;
> +
> +    sigemptyset(&waitset);
> +    sigaddset(&waitset, SIG_IPI);
> +    sigaddset(&waitset, SIGBUS);
> +
> +    do {
> +        r = sigtimedwait(&waitset, &siginfo, &ts);
> +        if (r == -1 && !(errno == EAGAIN || errno == EINTR)) {
> +            perror("sigtimedwait");
> +            exit(1);
> +        }
> +
> +        switch (r) {
> +#ifdef CONFIG_IOTHREAD
> +        case SIGBUS:
> +            if (kvm_on_sigbus_vcpu(env, siginfo.si_code, siginfo.si_addr)) {
> +                sigbus_reraise();
> +            }
> +            break;
> +#endif
> +        default:
> +            break;
> +        }
> +
> +        r = sigpending(&chkset);
> +        if (r == -1) {
> +            perror("sigpending");
> +            exit(1);
> +        }
> +    } while (sigismember(&chkset, SIG_IPI) || sigismember(&chkset, SIGBUS));
> +}
> +
>  #else /* _WIN32 */
>  
>  HANDLE qemu_event_handle;
> @@ -292,6 +331,10 @@ static void qemu_event_increment(void)
>  static void qemu_kvm_init_cpu_signals(CPUState *env)
>  {
>  }
> +
> +static void qemu_kvm_eat_signals(CPUState *env)
> +{
> +}
>  #endif /* _WIN32 */
>  
>  #ifndef CONFIG_IOTHREAD
> @@ -631,43 +674,6 @@ static void sigbus_handler(int n, struct 
> qemu_signalfd_siginfo *siginfo,
>      }
>  }
>  
> -static void qemu_kvm_eat_signals(CPUState *env)
> -{
> -    struct timespec ts = { 0, 0 };
> -    siginfo_t siginfo;
> -    sigset_t waitset;
> -    sigset_t chkset;
> -    int r;
> -
> -    sigemptyset(&waitset);
> -    sigaddset(&waitset, SIG_IPI);
> -    sigaddset(&waitset, SIGBUS);
> -
> -    do {
> -        r = sigtimedwait(&waitset, &siginfo, &ts);
> -        if (r == -1 && !(errno == EAGAIN || errno == EINTR)) {
> -            perror("sigtimedwait");
> -            exit(1);
> -        }
> -
> -        switch (r) {
> -        case SIGBUS:
> -            if (kvm_on_sigbus_vcpu(env, siginfo.si_code, siginfo.si_addr)) {
> -                sigbus_reraise();
> -            }
> -            break;
> -        default:
> -            break;
> -        }
> -
> -        r = sigpending(&chkset);
> -        if (r == -1) {
> -            perror("sigpending");
> -            exit(1);
> -        }
> -    } while (sigismember(&chkset, SIG_IPI) || sigismember(&chkset, SIGBUS));
> -}
> -
>  static void qemu_kvm_wait_io_event(CPUState *env)
>  {
>      while (!cpu_has_work(env))
> @@ -932,6 +938,8 @@ static int qemu_cpu_exec(CPUState *env)
>  
>  bool cpu_exec_all(void)
>  {
> +    int r;
> +
>      if (next_cpu == NULL)
>          next_cpu = first_cpu;
>      for (; next_cpu != NULL && !exit_request; next_cpu = next_cpu->next_cpu) 
> {
> @@ -943,7 +951,11 @@ bool cpu_exec_all(void)
>          if (qemu_alarm_pending())
>              break;
>          if (cpu_can_run(env)) {
> -            if (qemu_cpu_exec(env) == EXCP_DEBUG) {
> +            r = qemu_cpu_exec(env);
> +            if (kvm_enabled()) {
> +                qemu_kvm_eat_signals(env);
> +            }
> +            if (r == EXCP_DEBUG) {
>                  break;
>              }

As mentioned before, signal processing should be independent of
cpu_can_run (still want to process SIGALRM if vm is stopped, for
example).