From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Jan Beulich" <JBeulich@novell.com>
Subject: APIC handling on x86-64
Date: Fri, 17 Mar 2006 17:49:40 +0100
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As we had a report of a problem booting Xen on an IBM x460, dying on the BUG_ON() in init_apic_ldr() in
xen/include/asm-x86/mach-summit/mach_apic.h, I started comparing 32- and 64-bit APIC handling. Quickly I found that the
same case is handled gracefully in 64-bits, by just tying any extra CPUs to the highest bit. (I suppose, will try to
verify this with the originator, that the same machine also doesn't boot with native 32-bit Linux, as the exact same
issue should exist there).
While doing the same generally shouldn't be a problem, I wonder why this hasn't been discovered so far and how many
else differences there exist.

Thanks, Jan