>From 8e6c2f27782859b657faef508c6b56c2068af533 Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Wed, 17 Aug 2011 10:10:59 +0200 Subject: [PATCH] UBUNTU: (upstream) xen: Do not enable PV IPIs when vector callback not present Fix regression for HVM case on older (<4.1.1) hypervisors caused by commit 99bbb3a84a99cd04ab16b998b20f01a72cfa9f4f Author: Stefano Stabellini Date: Thu Dec 2 17:55:10 2010 +0000 xen: PV on HVM: support PV spinlocks and IPIs This change replaced the SMP operations with event based handlers without taking into account that this only works when the hypervisor supports callback vectors. This causes unexplainable hangs early on boot for HVM guests with more than one CPU. BugLink: http://bugs.launchpad.net/bugs/791850 Signed-off-by: Stefan Bader --- arch/x86/xen/smp.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c index b4533a8..e79dbb9 100644 --- a/arch/x86/xen/smp.c +++ b/arch/x86/xen/smp.c @@ -521,8 +521,6 @@ static void __init xen_hvm_smp_prepare_cpus(unsigned int max_cpus) native_smp_prepare_cpus(max_cpus); WARN_ON(xen_smp_intr_init(0)); - if (!xen_have_vector_callback) - return; xen_init_lock_cpu(0); xen_init_spinlocks(); } @@ -546,6 +544,8 @@ static void xen_hvm_cpu_die(unsigned int cpu) void __init xen_hvm_smp_init(void) { + if (!xen_have_vector_callback) + return; smp_ops.smp_prepare_cpus = xen_hvm_smp_prepare_cpus; smp_ops.smp_send_reschedule = xen_smp_send_reschedule; smp_ops.cpu_up = xen_hvm_cpu_up; -- 1.7.4.1