[Xen-devel] [PATCH] hvm: correct time offset update in RTC write emulation

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

# HG changeset patch
# User Ian Campbell <ian.campbell@xxxxxxxxxx>
# Date 1268126608 0
# Node ID 3b292a8858d2340a2a47d98ccc7fde9070075a42
# Parent  e5d1ae8238cc5f028fd5790c7d658aaba133bb5a
hvm: correct time offset update in RTC write emulation

mktime takes a month in 1..12 form while tm->tm_mon contains 0..11 so
we need to add 1. Without this fix setting the month back or forward a
month inside the guest would lead to the wrong number of days being
added/subtracted.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>

diff -r e5d1ae8238cc -r 3b292a8858d2 xen/arch/x86/hvm/rtc.c
--- a/xen/arch/x86/hvm/rtc.c    Fri Feb 26 12:08:20 2010 +0000
+++ b/xen/arch/x86/hvm/rtc.c    Tue Mar 09 09:23:28 2010 +0000
@@ -165,7 +165,7 @@
       
     ASSERT(spin_is_locked(&s->lock));
 
-    before = mktime(tm->tm_year, tm->tm_mon, tm->tm_mday,
+    before = mktime(tm->tm_year, tm->tm_mon + 1, tm->tm_mday,
                    tm->tm_hour, tm->tm_min, tm->tm_sec);
     
     tm->tm_sec = from_bcd(s, s->hw.cmos_data[RTC_SECONDS]);
@@ -179,7 +179,7 @@
     tm->tm_mon = from_bcd(s, s->hw.cmos_data[RTC_MONTH]) - 1;
     tm->tm_year = from_bcd(s, s->hw.cmos_data[RTC_YEAR]) + 100;
 
-    after = mktime(tm->tm_year, tm->tm_mon, tm->tm_mday,
+    after = mktime(tm->tm_year, tm->tm_mon + 1, tm->tm_mday,
                    tm->tm_hour, tm->tm_min, tm->tm_sec);
 
     /* We use the guest's setting of the RTC to define the local-time 

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