Merge branch 'mingw' of git://qemu.weilnetz.de/qemu

* 'mingw' of git://qemu.weilnetz.de/qemu:
  qemu-timer: move timeBeginPeriod/timeEndPeriod to os-win32
  Release SMP restriction on Windows
  Ensure good ordering of memory instruction in cpu_exec
  Check effective suspension of TCG thread

4 files changed, 47 insertions, 38 deletions

diff --git a/cpu-exec.c b/cpu-exec.c
index 235ddeed78..31c089dac0 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -215,6 +215,14 @@ int cpu_exec(CPUArchState *env)
 
     cpu_single_env = env;
 
+    /* As long as cpu_single_env is null, up to the assignment just above,
+     * requests by other threads to exit the execution loop are expected to
+     * be issued using the exit_request global. We must make sure that our
+     * evaluation of the global value is performed past the cpu_single_env
+     * value transition point, which requires a memory barrier as well as
+     * an instruction scheduling constraint on modern architectures.  */
+    smp_mb();
+
     if (unlikely(exit_request)) {
         cpu->exit_request = 1;
     }
diff --git a/cpus.c b/cpus.c
index e919dd7fb6..97e9ab4c07 100644
--- a/cpus.c
+++ b/cpus.c
@@ -862,9 +862,29 @@ static void qemu_cpu_kick_thread(CPUState *cpu)
     }
 #else /* _WIN32 */
     if (!qemu_cpu_is_self(cpu)) {
-        SuspendThread(cpu->hThread);
+        CONTEXT tcgContext;
+
+        if (SuspendThread(cpu->hThread) == (DWORD)-1) {
+            fprintf(stderr, "qemu:%s: GetLastError:%d\n", __func__,
+                    GetLastError());
+            exit(1);
+        }
+
+        /* On multi-core systems, we are not sure that the thread is actually
+         * suspended until we can get the context.
+         */
+        tcgContext.ContextFlags = CONTEXT_CONTROL;
+        while (GetThreadContext(cpu->hThread, &tcgContext) != 0) {
+            continue;
+        }
+
         cpu_signal(0);
-        ResumeThread(cpu->hThread);
+
+        if (ResumeThread(cpu->hThread) == (DWORD)-1) {
+            fprintf(stderr, "qemu:%s: GetLastError:%d\n", __func__,
+                    GetLastError());
+            exit(1);
+        }
     }
 #endif
 }
diff --git a/os-win32.c b/os-win32.c
index 9673a81c7d..50b7f6f885 100644
--- a/os-win32.c
+++ b/os-win32.c
@@ -23,6 +23,7 @@
  * THE SOFTWARE.
  */
 #include <windows.h>
+#include <mmsystem.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <signal.h>
@@ -67,27 +68,19 @@ static BOOL WINAPI qemu_ctrl_handler(DWORD type)
     return TRUE;
 }
 
-void os_setup_early_signal_handling(void)
+static TIMECAPS mm_tc;
+
+static void os_undo_timer_resolution(void)
 {
-    /* Note: cpu_interrupt() is currently not SMP safe, so we force
-       QEMU to run on a single CPU */
-    HANDLE h;
-    DWORD_PTR mask, smask;
-    int i;
+    timeEndPeriod(mm_tc.wPeriodMin);
+}
 
+void os_setup_early_signal_handling(void)
+{
     SetConsoleCtrlHandler(qemu_ctrl_handler, TRUE);
-
-    h = GetCurrentProcess();
-    if (GetProcessAffinityMask(h, &mask, &smask)) {
-        for(i = 0; i < 32; i++) {
-            if (mask & (1 << i))
-                break;
-        }
-        if (i != 32) {
-            mask = 1 << i;
-            SetProcessAffinityMask(h, mask);
-        }
-    }
+    timeGetDevCaps(&mm_tc, sizeof(mm_tc));
+    timeBeginPeriod(mm_tc.wPeriodMin);
+    atexit(os_undo_timer_resolution);
 }
 
 /* Look for support files in the same directory as the executable.  */
diff --git a/qemu-timer.c b/qemu-timer.c
index 8fb5c75df7..b2d95e2fec 100644
--- a/qemu-timer.c
+++ b/qemu-timer.c
@@ -624,28 +624,14 @@ static void CALLBACK mm_alarm_handler(UINT uTimerID, UINT uMsg,
 static int mm_start_timer(struct qemu_alarm_timer *t)
 {
     timeGetDevCaps(&mm_tc, sizeof(mm_tc));
-
-    timeBeginPeriod(mm_tc.wPeriodMin);
-
-    mm_timer = timeSetEvent(mm_tc.wPeriodMin,   /* interval (ms) */
-                            mm_tc.wPeriodMin,   /* resolution */
-                            mm_alarm_handler,   /* function */
-                            (DWORD_PTR)t,       /* parameter */
-                            TIME_ONESHOT | TIME_CALLBACK_FUNCTION);
-
-    if (!mm_timer) {
-        fprintf(stderr, "Failed to initialize win32 alarm timer\n");
-        timeEndPeriod(mm_tc.wPeriodMin);
-        return -1;
-    }
-
     return 0;
 }
 
 static void mm_stop_timer(struct qemu_alarm_timer *t)
 {
-    timeKillEvent(mm_timer);
-    timeEndPeriod(mm_tc.wPeriodMin);
+    if (mm_timer) {
+        timeKillEvent(mm_timer);
+    }
 }
 
 static void mm_rearm_timer(struct qemu_alarm_timer *t, int64_t delta)
@@ -657,7 +643,9 @@ static void mm_rearm_timer(struct qemu_alarm_timer *t, int64_t delta)
         nearest_delta_ms = mm_tc.wPeriodMax;
     }
 
-    timeKillEvent(mm_timer);
+    if (mm_timer) {
+        timeKillEvent(mm_timer);
+    }
     mm_timer = timeSetEvent((UINT)nearest_delta_ms,
                             mm_tc.wPeriodMin,
                             mm_alarm_handler,