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

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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: Thomas Huth <thuth@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180627134410.4901-10-david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
This commit is contained in:
David Hildenbrand 2018-06-27 15:44:10 +02:00 committed by Cornelia Huck
parent 7c12f710ba
commit d66b43c896
1 changed files with 12 additions and 5 deletions
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17
target/s390x/cpu.c
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@ -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)
run_on_cpu(cs, s390_do_cpu_full_reset, RUN_ON_CPU_NULL);
#else
cpu_reset(cs);
#endif
/*
* 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 {
cpu_reset(cs);
}
scc->parent_realize(dev, &err);
out: