>Number:         37104
>Category:       port-xen
>Synopsis:       miss handling of rtc_offset on Xen kernel
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    port-xen-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Oct 10 16:50:00 +0000 2007
>Originator:     Ryo Tsuruta
>Release:        NetBSD 4.0_RC2
>Organization:
>Environment:
NetBSD uni.home.local 4.0_RC2 NetBSD 4.0_RC2 (1709-GDJ_XEN3_DOM0) #0: Sun Oct  7 01:43:36 JST 2007  root@uni.home.local:/usr/src/netbsd-4/obj/netbsd-4/src/sys/arch/i386/compile/1709-GDJ_XEN3_DOM0 i386
>Description:
rtc_offset does not reflect the current time.

  Wed Oct 10 16:19 UTC 2007
  Thu Oct 11 01:19 JST 2007

  % sysctl kern.rtc_offset
  kern.rtc_offset = -540 (JST)
  % env TZ=UTC+0 date
  Thu Oct 11 01:19:30 UTC 2007
  % env TZ=JST-9 date
  Thu Oct 11 10:19:36 JST 2007

>How-To-Repeat:
Change rtc_offset by "sysctl -w kern.rtc_offset=XX", then just type the date command.

>Fix:
I think we should store the UTC time to shadow_ts.
It seems working fine after I applied the patch.

  Wed Oct 10 16:30 UTC 2007
  Thu Oct 11 01:30 JST 2007

  % sysctl kern.rtc_offset
  kern.rtc_offset = -540 (JST)
  % env TZ=UTC+0 date
  Wed Oct 10 16:30:12 UTC 2007
  % env TZ=JST-9 date
  Thu Oct 11 01:30:22 JST 2007

--- src/sys/arch/xen/xen/clock.c.orig   2007-10-11 00:57:35.000000000 +0900
+++ src/sys/arch/xen/xen/clock.c        2007-10-07 01:37:39.000000000 +0900
@@ -123,7 +123,8 @@
        do {
                tversion = HYPERVISOR_shared_info->wc_version;
                x86_lfence();
-               shadow_ts.tv_sec = HYPERVISOR_shared_info->wc_sec;
+               shadow_ts.tv_sec =
+                       HYPERVISOR_shared_info->wc_sec + rtc_offset * 60;
                shadow_ts.tv_nsec = HYPERVISOR_shared_info->wc_nsec;
                x86_lfence();
        } while ((HYPERVISOR_shared_info->wc_version & 1) ||
@@ -132,7 +133,8 @@
        do {
                shadow_time_version = HYPERVISOR_shared_info->time_version2;
                x86_lfence();
-               shadow_ts.tv_sec = HYPERVISOR_shared_info->wc_sec;
+               shadow_ts.tv_sec =
+                       HYPERVISOR_shared_info->wc_sec + rtc_offset * 60;
                shadow_ts.tv_nsec = HYPERVISOR_shared_info->wc_usec;
                shadow_tsc_stamp = HYPERVISOR_shared_info->tsc_timestamp;
                shadow_system_time = HYPERVISOR_shared_info->system_time;