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[Qemu-devel] [RFC] Use cpu_get_icount as cpu_get_host_ticks fallback

From: Christopher Covington
Subject: [Qemu-devel] [RFC] Use cpu_get_icount as cpu_get_host_ticks fallback
Date: Fri, 18 Mar 2016 16:56:39 -0400

The previous increment-on-read fallback didn't increment fast
enough for some versions of grub.


Signed-off-by: Christopher Covington <address@hidden>
I unfortunately don't have the opportunity to fully test this right
now, but I'm sending it out nevertheless on the off chance that
someone else might.
 include/qemu/timer.h | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/include/qemu/timer.h b/include/qemu/timer.h
index d0946cb..60c6dd6 100644
--- a/include/qemu/timer.h
+++ b/include/qemu/timer.h
@@ -998,13 +998,12 @@ static inline int64_t cpu_get_host_ticks(void)
-/* The host CPU doesn't have an easily accessible cycle counter.
-   Just return a monotonically increasing value.  This will be
-   totally wrong, but hopefully better than nothing.  */
+/* The host CPU doesn't have an easily accessible cycle counter, so just return
+   the instruction count. This may make the CPU look like it has an IPC of
+   exactly 1, but that shouldn't cause any functional problems. */
 static inline int64_t cpu_get_host_ticks (void)
-    static int64_t ticks = 0;
-    return ticks++;
+    return cpu_get_icount();
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