From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20120205220951.204993240@pcw.home.local> Date: Sun, 05 Feb 2012 23:10:30 +0100 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ian Campbell , Konrad Rzeszutek Wilk , Greg KH Subject: [PATCH 41/91] xen/smp: Warn user why they keel over - nosmp or noapic and what to use instead. In-Reply-To: <0635750f5f06ed2ca212b91fcb5c4483@local> Sender: linux-kernel-owner@vger.kernel.org List-ID: 2.6.27-longterm review patch. If anyone has any objections, please let us know. ------------------ commit ed467e69f16e6b480e2face7bc5963834d025f91 upstream. 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 Acked-by: Ian Campbell Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Greg Kroah-Hartman --- arch/x86/xen/smp.c | 10 ++++++++++ 1 files changed, 10 insertions(+), 0 deletions(-) Index: longterm-2.6.27/arch/x86/xen/smp.c =================================================================== --- longterm-2.6.27.orig/arch/x86/xen/smp.c 2012-02-05 22:34:33.783914838 +0100 +++ longterm-2.6.27/arch/x86/xen/smp.c 2012-02-05 22:34:40.668915455 +0100 @@ -33,6 +33,7 @@ #include #include +#include #include "xen-ops.h" #include "mmu.h" @@ -182,6 +183,15 @@ { unsigned cpu; + 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);