| From | Paul Gortmaker <> | Subject | [v2.6.34-stable 033/165] xen/smp: Warn user why they keel over - nosmp or noapic and what to use instead. | Date | Wed, 15 Aug 2012 15:46:17 -0400 |
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From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
------------------- This is a commit scheduled for the next v2.6.34 longterm release. http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git If you see a problem with using this for longterm, please comment. -------------------
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 <Ian.Campbell@eu.citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> --- arch/x86/xen/smp.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c index d2dfbf5..9aac865 100644 --- a/arch/x86/xen/smp.c +++ b/arch/x86/xen/smp.c @@ -31,6 +31,7 @@ #include <xen/page.h> #include <xen/events.h> +#include <xen/hvc-console.h> #include "xen-ops.h" #include "mmu.h" @@ -181,6 +182,15 @@ static void __init xen_smp_prepare_cpus(unsigned int max_cpus) { 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); -- 1.7.12.rc2
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