1 files changed, 27 insertions, 7 deletions

diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
index 8491e5badd..7c20d9db12 100644
--- a/accel/tcg/cpu-exec.c
+++ b/accel/tcg/cpu-exec.c
@@ -40,6 +40,7 @@
 #include "exec/replay-core.h"
 #include "system/tcg.h"
 #include "exec/helper-proto-common.h"
+#include "tcg-accel-ops.h"
 #include "tb-jmp-cache.h"
 #include "tb-hash.h"
 #include "tb-context.h"
@@ -748,6 +749,22 @@ static inline bool cpu_handle_exception(CPUState *cpu, int *ret)
     return false;
 }
 
+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);
+}
+
 static inline bool icount_exit_request(CPUState *cpu)
 {
     if (!icount_enabled()) {
@@ -774,7 +791,8 @@ 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);
 
@@ -784,7 +802,7 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
     if (unlikely(cpu_test_interrupt(cpu, ~0))) {
         bql_lock();
         if (cpu_test_interrupt(cpu, CPU_INTERRUPT_DEBUG)) {
-            cpu->interrupt_request &= ~CPU_INTERRUPT_DEBUG;
+            cpu_reset_interrupt(cpu, CPU_INTERRUPT_DEBUG);
             cpu->exception_index = EXCP_DEBUG;
             bql_unlock();
             return true;
@@ -793,7 +811,7 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
             /* Do nothing */
         } else if (cpu_test_interrupt(cpu, CPU_INTERRUPT_HALT)) {
             replay_interrupt();
-            cpu->interrupt_request &= ~CPU_INTERRUPT_HALT;
+            cpu_reset_interrupt(cpu, CPU_INTERRUPT_HALT);
             cpu->halted = 1;
             cpu->exception_index = EXCP_HLT;
             bql_unlock();
@@ -840,7 +858,7 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
             }
         }
         if (cpu_test_interrupt(cpu, CPU_INTERRUPT_EXITTB)) {
-            cpu->interrupt_request &= ~CPU_INTERRUPT_EXITTB;
+            cpu_reset_interrupt(cpu, CPU_INTERRUPT_EXITTB);
             /* ensure that no TB jump will be modified as
                the program flow was changed */
             *last_tb = NULL;
@@ -851,9 +869,11 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
     }
 #endif /* !CONFIG_USER_ONLY */
 
-    /* Finally, check if we need to exit to the main loop.  */
-    if (unlikely(qatomic_read(&cpu->exit_request)) || icount_exit_request(cpu)) {
-        qatomic_set(&cpu->exit_request, 0);
+    /*
+     * Finally, check if we need to exit to the main loop.
+     * The corresponding store-release is in cpu_exit.
+     */
+    if (unlikely(qatomic_load_acquire(&cpu->exit_request)) || icount_exit_request(cpu)) {
         if (cpu->exception_index == -1) {
             cpu->exception_index = EXCP_INTERRUPT;
         }