I have trouble with getting Xen to properly use some of our SMP machines. When Xen boots, it first detects the processors, but later it reports (XEN) mtrr: v2.0 (20020519) (XEN) mtrr: your CPUs had inconsistent fixed MTRR settings (XEN) mtrr: probably your BIOS does not setup all CPUs. (XEN) mtrr: corrected configuration. Then xm info only lists one core. Pure Linux 2.6.10 with SMP is able to boot without complaints, and the exact same Xen kernel boots fine on some other SMP machines that we have... There might be three explanations to this (and probably a fourth, correct one, which I leave as an exercise to the reader :-) 1) Xen thinks that there is something wrong, while there in fact isn''t. 2) Linux does some magic to handle this, that Xen currently does not. 3) Linux is erroneously ignoring this error. Any ideas on how to solve this? /Lars _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On 27 Apr 2005, at 00:49, Lars Rasmusson wrote:> 1) Xen thinks that there is something wrong, while there in fact > isn''t. > 2) Linux does some magic to handle this, that Xen currently does not. > 3) Linux is erroneously ignoring this error. > > Any ideas on how to solve this?It''s unlikely that it has to anything to do with MTRR setup -- that message is just a warning. Linux doesn''t give it because you probably did not compile in the MTRR driver. Your best bet is to post the output from booting Xen (a debug build) and from booting plain Linux. Also you might want to add tracing around smpboot.c in particular to work out wher ethe seocndary CPUs are getting dropped. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
It might also be helpful to add some printks in cpu_init() in setup.c I have booted Xen on an 8way / 32way system and it runs fine. So I am sure that all the magic is there in Xen :-) Aravindh -----Original Message----- From: xen-devel-bounces@lists.xensource.com [mailto:xen-devel-bounces@lists.xensource.com] On Behalf Of Keir Fraser Sent: Wednesday, April 27, 2005 4:20 AM To: Lars Rasmusson Cc: xen-devel@lists.xensource.com Subject: Re: [Xen-devel] problem with SMP machine On 27 Apr 2005, at 00:49, Lars Rasmusson wrote:> 1) Xen thinks that there is something wrong, while there in fact > isn''t. > 2) Linux does some magic to handle this, that Xen currently does not. > 3) Linux is erroneously ignoring this error. > > Any ideas on how to solve this?It''s unlikely that it has to anything to do with MTRR setup -- that message is just a warning. Linux doesn''t give it because you probably did not compile in the MTRR driver. Your best bet is to post the output from booting Xen (a debug build) and from booting plain Linux. Also you might want to add tracing around smpboot.c in particular to work out wher ethe seocndary CPUs are getting dropped. -- Keir _______________________________________________ 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