Re: [PATCH] KVM: x86: fix kvmclock breakage from timers branch merge

Paolo Bonzini
2014-09-05T16:39:57Z

Il 05/09/2014 17:14, Thomas Gleixner ha scritto:
> So that means the code is correct. Now where is the bug?

In kernel/time/timekeeping.c?

We know that we should have

base_mono = wall_to_monotonic + xtime_sec

Instead it is

base_mono = wall_to_monotonic + xtime_sec
- seconds from boot time

which is... zero. Given this is the only use of base_mono in a
notifier, I wonder if it is as simple as this (which I don't have time
to test right now):

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index fb4a9c2cf8d9..f6807a85b8c9 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -443,9 +443,9 @@ static void timekeeping_update(struct timekeeper
*tk, unsigned int action)
ntp_clear();
}
update_vsyscall(tk);
- update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);

tk_update_ktime_data(tk);
+ update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);

if (action & TK_MIRROR)
memcpy(&shadow_timekeeper, &tk_core.timekeeper,

:)

Paolo

> Well hidden and still so obvious that it's even visible through the
> brown paperpag I'm wearing ...