[PATCH 12/19] accel/tcg: inline cpu_exit()

[Paolo Bonzini <pbonzini@redhat.com>]

Right now, cpu_exit() is not usable from all accelerators because it
includes a TCG-specific thread kick.  In fact, cpu_exit() doubles as
the TCG thread-kick via tcg_kick_vcpu_thread().

In preparation for changing that, inline cpu_exit() into
tcg_kick_vcpu_thread().  The direction of the calls can then be
reversed, with an accelerator-independent cpu_exit() calling into
qemu_vcpu_kick() rather than the opposite.

Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 accel/tcg/cpu-exec.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
index 9241bcadb5f..3ae545e888f 100644
--- a/accel/tcg/cpu-exec.c
+++ b/accel/tcg/cpu-exec.c
@@ -751,7 +751,16 @@ static inline bool cpu_handle_exception(CPUState *cpu, int *ret)
 
 void tcg_kick_vcpu_thread(CPUState *cpu)
 {
-    cpu_exit(cpu);
+    /*
+     * 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);
+
+    /* Ensure cpu_exec will see the exit request after TCG has exited.  */
+    qatomic_store_release(&cpu->neg.icount_decr.u16.high, -1);
 }
 
 static inline bool icount_exit_request(CPUState *cpu)
@@ -780,7 +789,8 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
     /* Clear the interrupt flag now since we're processing
      * cpu->interrupt_request and cpu->exit_request.
      * Ensure zeroing happens before reading cpu->exit_request or
-     * cpu->interrupt_request (see also smp_wmb in cpu_exit())
+     * cpu->interrupt_request (see also store-release in
+     * tcg_kick_vcpu_thread())
      */
     qatomic_set_mb(&cpu->neg.icount_decr.u16.high, 0);
 
-- 
2.51.0