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-rw-r--r--arch/x86/xen/enlighten.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index ddbd54a9b845..94a81f41e8a2 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -157,6 +157,21 @@ static void xen_vcpu_setup(int cpu)
BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
+ /*
+ * This path is called twice on PVHVM - first during bootup via
+ * smp_init -> xen_hvm_cpu_notify, and then if the VCPU is being
+ * hotplugged: cpu_up -> xen_hvm_cpu_notify.
+ * As we can only do the VCPUOP_register_vcpu_info once lets
+ * not over-write its result.
+ *
+ * For PV it is called during restore (xen_vcpu_restore) and bootup
+ * (xen_setup_vcpu_info_placement). The hotplug mechanism does not
+ * use this function.
+ */
+ if (xen_hvm_domain()) {
+ if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu))
+ return;
+ }
if (cpu < MAX_VIRT_CPUS)
per_cpu(xen_vcpu,cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];