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authorJosé Pekkarinen <jose.pekkarinen@nokia.com>2016-05-18 13:18:31 +0300
committerJosé Pekkarinen <jose.pekkarinen@nokia.com>2016-05-18 13:42:15 +0300
commit437fd90c0250dee670290f9b714253671a990160 (patch)
treeb871786c360704244a07411c69fb58da9ead4a06 /qemu/docs/win32-qemu-event.promela
parent5bbd6fe9b8bab2a93e548c5a53b032d1939eec05 (diff)
These changes are the raw update to qemu-2.6.
Collission happened in the following patches: migration: do cleanup operation after completion(738df5b9) Bug fix.(1750c932f86) kvmclock: add a new function to update env->tsc.(b52baab2) The code provided by the patches was already in the upstreamed version. Change-Id: I3cc11841a6a76ae20887b2e245710199e1ea7f9a Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>
Diffstat (limited to 'qemu/docs/win32-qemu-event.promela')
-rw-r--r--qemu/docs/win32-qemu-event.promela98
1 files changed, 98 insertions, 0 deletions
diff --git a/qemu/docs/win32-qemu-event.promela b/qemu/docs/win32-qemu-event.promela
new file mode 100644
index 000000000..c446a7155
--- /dev/null
+++ b/qemu/docs/win32-qemu-event.promela
@@ -0,0 +1,98 @@
+/*
+ * This model describes the implementation of QemuEvent in
+ * util/qemu-thread-win32.c.
+ *
+ * Author: Paolo Bonzini <pbonzini@redhat.com>
+ *
+ * This file is in the public domain. If you really want a license,
+ * the WTFPL will do.
+ *
+ * To verify it:
+ * spin -a docs/event.promela
+ * gcc -O2 pan.c -DSAFETY
+ * ./a.out
+ */
+
+bool event;
+int value;
+
+/* Primitives for a Win32 event */
+#define RAW_RESET event = false
+#define RAW_SET event = true
+#define RAW_WAIT do :: event -> break; od
+
+#if 0
+/* Basic sanity checking: test the Win32 event primitives */
+#define RESET RAW_RESET
+#define SET RAW_SET
+#define WAIT RAW_WAIT
+#else
+/* Full model: layer a userspace-only fast path on top of the RAW_*
+ * primitives. SET/RESET/WAIT have exactly the same semantics as
+ * RAW_SET/RAW_RESET/RAW_WAIT, but try to avoid invoking them.
+ */
+#define EV_SET 0
+#define EV_FREE 1
+#define EV_BUSY -1
+
+int state = EV_FREE;
+
+int xchg_result;
+#define SET if :: state != EV_SET -> \
+ atomic { /* xchg_result=xchg(state, EV_SET) */ \
+ xchg_result = state; \
+ state = EV_SET; \
+ } \
+ if :: xchg_result == EV_BUSY -> RAW_SET; \
+ :: else -> skip; \
+ fi; \
+ :: else -> skip; \
+ fi
+
+#define RESET if :: state == EV_SET -> atomic { state = state | EV_FREE; } \
+ :: else -> skip; \
+ fi
+
+int tmp1, tmp2;
+#define WAIT tmp1 = state; \
+ if :: tmp1 != EV_SET -> \
+ if :: tmp1 == EV_FREE -> \
+ RAW_RESET; \
+ atomic { /* tmp2=cas(state, EV_FREE, EV_BUSY) */ \
+ tmp2 = state; \
+ if :: tmp2 == EV_FREE -> state = EV_BUSY; \
+ :: else -> skip; \
+ fi; \
+ } \
+ if :: tmp2 == EV_SET -> tmp1 = EV_SET; \
+ :: else -> tmp1 = EV_BUSY; \
+ fi; \
+ :: else -> skip; \
+ fi; \
+ assert(tmp1 != EV_FREE); \
+ if :: tmp1 == EV_BUSY -> RAW_WAIT; \
+ :: else -> skip; \
+ fi; \
+ :: else -> skip; \
+ fi
+#endif
+
+active proctype waiter()
+{
+ if
+ :: !value ->
+ RESET;
+ if
+ :: !value -> WAIT;
+ :: else -> skip;
+ fi;
+ :: else -> skip;
+ fi;
+ assert(value);
+}
+
+active proctype notifier()
+{
+ value = true;
+ SET;
+}