Red Hat Bugzilla – Bug 439254
Xen hypervisor doesn't detect Penryn cpu_model correctly
Last modified: 2008-05-21 11:12:55 EDT
n the course of getting bz 253056 resolved, I just discovered that Penryn-class CPUs show up as cpu model 7 in the Xen Hypervisor under RHEL5.2, rather than 23 like they should. There is a small patch that will fix this, which I will port immediately. One effect of the bug is that these new chips are treated like a Pentium 3 instead of a Core 2 chip, for some purposes, such as oprofile. I'm not sure of all the repercussions of that yet, but it's A Bad Thing (TM). Here's the upstream patch: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=f5f786d0455c359c554b8f74783f887c0a2c9fac
Created attachment 299379 [details] fix to generic_identify to use extended model About to test this patch, fix to generic_identify() function to use the extended model field to calculate the correct cpu_model. It was actually being done correctly in early_cpu_detect() already.
Add dependency.
Setting flags. This bz is closely related to bz 235056 which addresses the same issue on bare metal, but neglected the equivalent Xen kernel changes. This is deemed very low risk and needs to be considered for RHEL 5.2.
in kernel-2.6.18-88.el5 You can download this test kernel from http://people.redhat.com/dzickus/el5
Confirmed fix is in the -92.el5 kernel.
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on the solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHBA-2008-0314.html