Commit d66b43c8 authored by David Hildenbrand's avatar David Hildenbrand Committed by Cornelia Huck
Browse files

s390x/tcg: fix CPU hotplug with single-threaded TCG 



run_on_cpu() doesn't seem to work reliably until the CPU has been fully
created if the single-threaded TCG main loop is already running.

Therefore, hotplugging a CPU under single-threaded TCG does currently
not work. We should use the direct call instead of going via
run_on_cpu().

So let's use run_on_cpu() for KVM only - KVM requires it due to the initial
CPU reset ioctl. As a nice side effect, we get rid of the ifdef.

Reviewed-by: default avatarThomas Huth <thuth@redhat.com>
Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
Message-Id: <20180627134410.4901-10-david@redhat.com>
Signed-off-by: default avatarCornelia Huck <cohuck@redhat.com>
parent 7c12f710

target/s390x/cpu.c

+12 −5
Original line number Diff line number Diff line
@@ -218,11 +218,18 @@ static void s390_cpu_realizefn(DeviceState *dev, Error **errp) 
#endif

    s390_cpu_gdb_init(cs);

    qemu_init_vcpu(cs);

#if !defined(CONFIG_USER_ONLY)



    /*

     * KVM requires the initial CPU reset ioctl to be executed on the target

     * CPU thread. CPU hotplug under single-threaded TCG will not work with

     * run_on_cpu(), as run_on_cpu() will not work properly if called while

     * the main thread is already running but the CPU hasn't been realized.

     */

    if (kvm_enabled()) {

        run_on_cpu(cs, s390_do_cpu_full_reset, RUN_ON_CPU_NULL);

#else

    } else {

        cpu_reset(cs);

#endif

    }



    scc->parent_realize(dev, &err);

out: