hvm: correct RTC time offset update error due to tm->tm_year

tm->tm_year in rtc.c is year number offsetting from 1900. So it is
necessary to add the offset 1900 when calling mktime funtion in
Xen. Otherwise, the calculation result of mktime is incorrect.

Signed-off-by: Annie Li <annie.li@oracle.com>
Committed-by: Keir Fraser <keir@xen.org>

diff --git a/xen/arch/x86/hvm/rtc.c b/xen/arch/x86/hvm/rtc.c
index 81a74a33c631a76ca00242e4c3eff6a84b7e6e65..e1139da89fd5a8450047da9640188b211c745734 100644 (file)
--- a/xen/arch/x86/hvm/rtc.c
+++ b/xen/arch/x86/hvm/rtc.c
@@ -33,6 +33,8 @@
 #define vrtc_domain(x) (container_of((x), struct domain, \
                                      arch.hvm_domain.pl_time.vrtc))
 #define vrtc_vcpu(x)   (pt_global_vcpu_target(vrtc_domain(x)))
+#define epoch_year     1900
+#define get_year(x)    (x + epoch_year)
 
 static void rtc_periodic_cb(struct vcpu *v, void *opaque)
 {
@@ -165,7 +167,7 @@ static void rtc_set_time(RTCState *s)
       
     ASSERT(spin_is_locked(&s->lock));
 
-    before = mktime(tm->tm_year, tm->tm_mon + 1, tm->tm_mday,
+    before = mktime(get_year(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 +181,7 @@ static void rtc_set_time(RTCState *s)
     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 + 1, tm->tm_mday,
+    after = mktime(get_year(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 
@@ -257,7 +259,7 @@ static void rtc_next_second(RTCState *s)
                 if ( (unsigned)tm->tm_wday >= 7 )
                     tm->tm_wday = 0;
                 days_in_month = get_days_in_month(tm->tm_mon, 
-                                                  tm->tm_year + 1900);
+                                                  get_year(tm->tm_year));
                 tm->tm_mday++;
                 if ( tm->tm_mday < 1 )
                 {