Commit ed467e69 authored Sep 01, 2011 by Konrad Rzeszutek Wilk

xen/smp: Warn user why they keel over - nosmp or noapic and what to use instead.

We have hit a couple of customer bugs where they would like to
use those parameters to run an UP kernel - but both of those
options turn of important sources of interrupt information so
we end up not being able to boot. The correct way is to
pass in 'dom0_max_vcpus=1' on the Xen hypervisor line and
the kernel will patch itself to be a UP kernel.

Fixes bug: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=637308



CC: stable@kernel.org
Acked-by: Ian Campbell <Ian.Campbell@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

parent d198d499

arch/x86/xen/smp.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -32,6 +32,7 @@
		#include <xen/page.h>
		#include <xen/events.h>

		#include <xen/hvc-console.h>
		#include "xen-ops.h"
		#include "mmu.h"

		@@ -207,6 +208,15 @@ static void __init xen_smp_prepare_cpus(unsigned int max_cpus)
		unsigned cpu;
		unsigned int i;

		if (skip_ioapic_setup) {
		char *m = (max_cpus == 0) ?
		"The nosmp parameter is incompatible with Xen; " \
		"use Xen dom0_max_vcpus=1 parameter" :
		"The noapic parameter is incompatible with Xen";

		xen_raw_printk(m);
		panic(m);
		}
		xen_init_lock_cpu(0);

		smp_store_cpu_info(0);