[src/trunk]: src/sys/arch/xen/include Explain why we hardwire lapic_cpu_numbe...

[bouyer <bouyer%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/6a9e8157f5ee
branches:  trunk
changeset: 758732:6a9e8157f5ee
user:      bouyer <bouyer%NetBSD.org@localhost>
date:      Sun Nov 14 13:40:31 2010 +0000

description:
Explain why we hardwire lapic_cpu_number() to 0 on Xen.

diffstat:

 sys/arch/xen/include/i82489var.h |  8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diffs (16 lines):

diff -r 82e509089141 -r 6a9e8157f5ee sys/arch/xen/include/i82489var.h
--- a/sys/arch/xen/include/i82489var.h  Sun Nov 14 13:33:20 2010 +0000
+++ b/sys/arch/xen/include/i82489var.h  Sun Nov 14 13:40:31 2010 +0000
@@ -1,5 +1,11 @@
-/*     $NetBSD: i82489var.h,v 1.1 2006/09/28 18:53:15 bouyer Exp $     */
+/*     $NetBSD: i82489var.h,v 1.2 2010/11/14 13:40:31 bouyer Exp $     */
 
 #include <x86/i82489var.h>
+
+/*
+ * Xen doesn't give acces to the lapic. In addition, the lapic number provided
+ * by the dom0 to Xen when setting up iopics is ignored, the hypervisor will
+ * decide itself to which physical CPU the interrupt should be routed to.
+ */
 #undef lapic_cpu_number
 #define lapic_cpu_number() (0)