Re: [Qemu-devel] [PATCH v2 2/8] Allow to use pause_all_vcpus from VCPU context

[Blue Swirl]

On Fri, Feb 10, 2012 at 18:31, Jan Kiszka <address@hidden> wrote:
> In order to perform critical manipulations on the VM state in the
> context of a VCPU, specifically code patching, stopping and resuming of
> all VCPUs may be necessary. resume_all_vcpus is already compatible, now
> enable pause_all_vcpus for this use case by stopping the calling context
> before starting to wait for the whole gang.
>
> CC: Paolo Bonzini <address@hidden>
> Signed-off-by: Jan Kiszka <address@hidden>
> ---
>  cpus.c |   12 ++++++++++++
>  1 files changed, 12 insertions(+), 0 deletions(-)
>
> diff --git a/cpus.c b/cpus.c
> index d0c8340..5adfc6b 100644
> --- a/cpus.c
> +++ b/cpus.c
> @@ -870,6 +870,18 @@ void pause_all_vcpus(void)
>         penv = (CPUState *)penv->next_cpu;
>     }
>
> +    if (!qemu_thread_is_self(&io_thread)) {
> +        cpu_stop_current();
> +        if (!kvm_enabled()) {
> +            while (penv) {
> +                penv->stop = 0;
> +                penv->stopped = 1;
> +                penv = (CPUState *)penv->next_cpu;

The cast is useless, next_cpu is already CPUState *. I wonder why it
is used in other cases too.

> +            }
> +            return;
> +        }
> +    }
> +
>     while (!all_vcpus_paused()) {
>         qemu_cond_wait(&qemu_pause_cond, &qemu_global_mutex);
>         penv = first_cpu;
> --
> 1.7.3.4
>
>