From: Andrew Cooper <andrew.cooper3@citrix.com>
To: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
Christoph Egger <christoph.egger@amd.com>,
Wei Huang <wei.huang2@amd.com>
Subject: AMD Magny-Cours and HPET
Date: Tue, 16 Aug 2011 10:47:13 +0100 [thread overview]
Message-ID: <4E4A3CA1.3050100@citrix.com> (raw)
Hello,
We have had a bug raised against Xen-3.4 that the kexec path fails, on
HP BL465c G7 blades. The problem does not reproduce on any other AMD
machines I have to hand.
On further investigation, it appears that if the crashing cpu is #0,
then the kexec path hangs forever trying to grab the already locked
legacy_hpet_event.lock in hpet_disable_legacy_broadcast(). Removing the
lock/unlock pair causes the kexec crash path to work as expected.
If the crashing cpu is not #0, then local_time_calibration() gets
worried and dumps the calibration data, and hangs at some later point
which I have yet to find. This hang happens while performing the NMI
shootdown of other cpus.
The support engineer who raised the bug says that it doesn't occur with
Xen-4.1. Is there anything architecturally new in the Magny-Cours
processors which might explain this behavior?
I am unwilling to try and backport the hpet code from Xen-4.x without
understanding the problem, although it is a possible solution.
Thanks
--
Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer
T: +44 (0)1223 225 900, http://www.citrix.com
next reply other threads:[~2011-08-16 9:47 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-16 9:47 Andrew Cooper [this message]
2011-08-16 10:09 ` AMD Magny-Cours and HPET Jan Beulich
2011-08-16 12:32 ` Andrew Cooper
2011-08-16 12:55 ` Jan Beulich
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