From d509af9b5a31e2e836da6bd042d941e0ec54f468 Mon Sep 17 00:00:00 2001 From: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Date: Wed, 17 Aug 2011 15:15:00 +0200 Subject: [PATCH] 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 ebe8c44fc610abbf6726bf720acbe3862b13a0c1 Author: Stefano Stabellini <stefano.stabellini@eu.citrix.com> 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 CC: stable@kernel.org Signed-off-by: Stefan Bader <stefan.bader@canonical.com> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Tested-and-Reported-by: Stefan Bader <stefan.bader@canonical.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> --- arch/x86/xen/smp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c index b4533a86d7e41..e79dbb95482b8 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; -- 2.39.5