accel/tcg: Complete cpu initialization before registration

Delay cpu_list_add until realize is complete, so that cross-cpu
interaction does not happen with incomplete cpu state.  For this,
we must delay plugin initialization out of tcg_exec_realizefn,
because no cpu_index has been assigned.

Fixes a problem with cross-cpu jump cache flushing, when the
jump cache has not yet been allocated.

Fixes: a976a99a2975 ("include/hw/core: Create struct CPUJumpCache")
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reported-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 9 insertions, 1 deletions

diff --git a/cpu.c b/cpu.c
index 2a09b05205..4a7d865427 100644
--- a/cpu.c
+++ b/cpu.c
@@ -134,15 +134,23 @@ void cpu_exec_realizefn(CPUState *cpu, Error **errp)
     /* cache the cpu class for the hotpath */
     cpu->cc = CPU_GET_CLASS(cpu);
 
-    cpu_list_add(cpu);
     if (!accel_cpu_realizefn(cpu, errp)) {
         return;
     }
+
     /* NB: errp parameter is unused currently */
     if (tcg_enabled()) {
         tcg_exec_realizefn(cpu, errp);
     }
 
+    /* Wait until cpu initialization complete before exposing cpu. */
+    cpu_list_add(cpu);
+
+    /* Plugin initialization must wait until cpu_index assigned. */
+    if (tcg_enabled()) {
+        qemu_plugin_vcpu_init_hook(cpu);
+    }
+
 #ifdef CONFIG_USER_ONLY
     assert(qdev_get_vmsd(DEVICE(cpu)) == NULL ||
            qdev_get_vmsd(DEVICE(cpu))->unmigratable);