Re: Upgrade from xen-4.1-testing to xen-unstable report

[Lin Ming <mlin@ss.pku.edu.cn>]

On Thu, 2012-04-12 at 15:03 +0100, Ian Campbell wrote:
> On Thu, 2012-04-12 at 13:50 +0100, Lin Ming wrote:
> > On Thu, 2012-04-12 at 07:08 +0000, Ian Campbell wrote:
> > > On Wed, 2012-04-11 at 22:23 +0100, Teck Choon Giam wrote:
> > > > Hi,
> > > > 
> > > > This is just my experience about issues I encountered when upgrade
> > > > from xen-4.1-testing changeset 23277:80130491806f to xen-unstable
> > > > changeset 25191:a95fc7decc83.
> > > > 
> > > > 1. Immediately after upgrade, xl list show such error:
> > > > 
> > > > # xl list
> > > > libxl: error: libxl.c:506:libxl_list_domain: geting domain info list:
> > > > Permission denied
> > > > libxl_domain_infolist failed.
> > > > 
> > > > After a reboot, it is fine.  Any idea why such behaviour?  Imagine if
> > > > there are running domUs... this might cause issues to shutdown?  I
> > > > will downgrade and repeat such test to confirm.  Might be worth a note
> > > > in upgrading note about this if this is intended?
> > > 
> > > The tools and the hypervisor are a matched pair so you would need to
> > > reboot the system in order to use the new tools. This has always been
> > > the case with Xen upgrades.
> > > 
> > > > 2. localtime setting not working.  Set to localtime=1 doesn't seems to
> > > > work whereby setting rtc_timeoffset works.  Any idea?
> > > 
> > > I've CC'd Lin Ming who implemented both of those.
> > 
> > Just did a quick gdb debug, seems libxl__domain_build_info_setdefault
> > was called 3 times. So below statement was executed 3 times too.
> > 
> > b_info->rtc_timeoffset += tm->tm_gmtoff;
> 
> Oh, that sounds like the problem. The setdefault functions are supposed
> to be idempotent, IOW calling it two or more times should give the same
> result as calling it just once.
> 
> I think you need to move this logic from setdefault
>     if (libxl_defbool_val(b_info->localtime)) {
>         time_t t;
>         struct tm *tm;
> 
>         t = time(NULL);
>         tm = localtime(&t);
> 
>         b_info->rtc_timeoffset += tm->tm_gmtoff;
>     }
> 
> into libxl__build_pre and do that calculation on a temporary variable
> whjich you pass to xc_domain_set_time_offset rather than modifying
> b_info.

How about below patch?

>From e06589cb5f1efd885f9589405d0f4ecc97427ad6 Mon Sep 17 00:00:00 2001
From: Lin Ming <mlin@ss.pku.edu.cn>
Date: Thu, 12 Apr 2012 22:36:24 +0800
Subject: [PATCH] libxl: fix rtc_timeoffset setting

libxl__domain_build_info_setdefault may be called several times, so
rtc_timeoffset can't be set in it.

Move rtc_timeoffset setting logic to libxl__build_pre.

Reported-by: Teck Choon Giam <giamteckchoon@gmail.com>
Signed-off-by: Lin Ming <mlin@ss.pku.edu.cn>
---
 tools/libxl/libxl_create.c |    9 ---------
 tools/libxl/libxl_dom.c    |   17 +++++++++++++++--
 2 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index e63c7bd..e706124 100644
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -127,15 +127,6 @@ int libxl__domain_build_info_setdefault(libxl__gc *gc,
         b_info->target_memkb = b_info->max_memkb;
 
     libxl_defbool_setdefault(&b_info->localtime, false);
-    if (libxl_defbool_val(b_info->localtime)) {
-        time_t t;
-        struct tm *tm;
-
-        t = time(NULL);
-        tm = localtime(&t);
-
-        b_info->rtc_timeoffset += tm->tm_gmtoff;
-    }
 
     libxl_defbool_setdefault(&b_info->disable_migrate, false);
 
diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index 0bdd654..91c4bd8 100644
--- a/tools/libxl/libxl_dom.c
+++ b/tools/libxl/libxl_dom.c
@@ -65,6 +65,8 @@ int libxl__build_pre(libxl__gc *gc, uint32_t domid,
     libxl_ctx *ctx = libxl__gc_owner(gc);
     int tsc_mode;
     char *xs_domid, *con_domid;
+    uint32_t rtc_timeoffset;
+
     xc_domain_max_vcpus(ctx->xch, domid, info->max_vcpus);
     libxl_set_vcpuaffinity_all(ctx, domid, info->max_vcpus, &info->cpumap);
     xc_domain_setmaxmem(ctx->xch, domid, info->target_memkb + LIBXL_MAXMEM_CONSTANT);
@@ -91,8 +93,19 @@ int libxl__build_pre(libxl__gc *gc, uint32_t domid,
     if (libxl_defbool_val(info->disable_migrate))
         xc_domain_disable_migrate(ctx->xch, domid);
 
-    if (info->rtc_timeoffset)
-        xc_domain_set_time_offset(ctx->xch, domid, info->rtc_timeoffset);
+    rtc_timeoffset = info->rtc_timeoffset;
+    if (libxl_defbool_val(info->localtime)) {
+        time_t t;
+        struct tm *tm;
+
+        t = time(NULL);
+        tm = localtime(&t);
+
+        rtc_timeoffset += tm->tm_gmtoff;
+    }
+
+    if (rtc_timeoffset)
+        xc_domain_set_time_offset(ctx->xch, domid, rtc_timeoffset);
 
     if (info->type == LIBXL_DOMAIN_TYPE_HVM) {
         unsigned long shadow;
-- 
1.7.2.5



> 
> Ian.
> 
>