tcg/user: do not set exit_request gratuitously

Whenever user-mode emulation needs to go all the way out of the cpu
exec loop, it uses cpu_exit(), which already sets cpu->exit_request.

Therefore, there is no need for tcg_kick_vcpu_thread() to set
cpu->exit_request again outside system emulation.

Reviewed-by: Igor Mammedov <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
Message-Id: <[email protected]>

Author: bonzini

accel/tcg/cpu-exec.c

@@ -751,13 +751,15 @@ static inline bool cpu_handle_exception(CPUState *cpu, int *ret)
 
 void tcg_kick_vcpu_thread(CPUState *cpu)
 {
+#ifndef CONFIG_USER_ONLY
     /*
      * Ensure cpu_exec will see the reason why the exit request was set.
      * FIXME: this is not always needed.  Other accelerators instead
      * read interrupt_request and set exit_request on demand from the
      * CPU thread; see kvm_arch_pre_run() for example.
      */
     qatomic_store_release(&cpu->exit_request, true);
+#endif
 
     /* Ensure cpu_exec will see the exit request after TCG has exited.  */
     qatomic_store_release(&cpu->neg.icount_decr.u16.high, -1);