I know I''ve asked vaguely the same questions before, but when dom0 reboots, is it dom0 or xen that actually reboots the machine? What about when, say, softdog (the software watchdog kernel module) does a reboot? I ask because if I say ''reboot'', one system I have just hangs, with the monitor in ''standby'' mode (eg no signal), whereas if I kill the watchdog daemon (with softdog loaded with nowayout=1), it reboots fine, but obviously doesn''t do a clean shutdown. Is there a way to change the style of reboot that xen uses? Or should I be looking at asking dom0 to reboot differently? Thanks James _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Following up to my own post... it looks like in xen/arch/x86/domain.c there is a variable called ''reboot_mode'', which is written to physical address 0x472 on reboot to tell the BIOS what to do. This would contain 0x1234 to do a ''warm'' boot, and 0 (or anything else???) otherwise. But nowhere in the xen directory can I see this variable get initialised... Any ideas? Thanks James> -----Original Message----- > From: xen-devel-bounces@lists.xensource.com [mailto:xen-devel- > bounces@lists.xensource.com] On Behalf Of James Harper > Sent: Friday, 30 December 2005 10:42 > To: xen-devel@lists.xensource.com > Subject: [Xen-devel] xen and reboots > > I know I''ve asked vaguely the same questions before, but when dom0 > reboots, is it dom0 or xen that actually reboots the machine? > > What about when, say, softdog (the software watchdog kernel module)does> a reboot? > > I ask because if I say ''reboot'', one system I have just hangs, withthe> monitor in ''standby'' mode (eg no signal), whereas if I kill thewatchdog> daemon (with softdog loaded with nowayout=1), it reboots fine, but > obviously doesn''t do a clean shutdown. > > Is there a way to change the style of reboot that xen uses? Or shouldI> be looking at asking dom0 to reboot differently? > > Thanks > > James > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On 29 Dec 2005, at 23:56, James Harper wrote:> Following up to my own post... it looks like in xen/arch/x86/domain.c > there is a variable called ''reboot_mode'', which is written to physical > address 0x472 on reboot to tell the BIOS what to do. This would contain > 0x1234 to do a ''warm'' boot, and 0 (or anything else???) otherwise. But > nowhere in the xen directory can I see this variable get initialised... > > Any ideas?Xen''s reboot code is a dumb rip-off from Linux. Some of the parameters for choosing type of reboot are not ''wired up''. What''s there now seems to work on the vast majority of systems. I don''t understand how different reboot triggers in domain0 can have an effect on whether the system actually reboots or not. I believe the Xen reboot code is unaffected by guests. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel