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>
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index e79dbb9..d4fc6d4 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -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 @@
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);
