2 files changed, 66 insertions, 50 deletions

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index c7f6b1f90efa..a9ba14ac3aea 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -140,7 +140,9 @@ RESERVE_BRK(shared_info_page_brk, PAGE_SIZE);
 __read_mostly int xen_have_vector_callback;
 EXPORT_SYMBOL_GPL(xen_have_vector_callback);
 
-static struct notifier_block xen_cpu_notifier;
+static int xen_cpu_up_prepare(unsigned int cpu);
+static int xen_cpu_up_online(unsigned int cpu);
+static int xen_cpu_dead(unsigned int cpu);
 
 /*
  * Point at some empty memory to start with. We map the real shared_info
@@ -1541,6 +1543,24 @@ static void __init xen_dom0_set_legacy_features(void)
         x86_platform.legacy.rtc = 1;
 }
 
+static int xen_cpuhp_setup(void)
+{
+        int rc;
+
+        rc = cpuhp_setup_state_nocalls(CPUHP_XEN_PREPARE,
+                                       "XEN_HVM_GUEST_PREPARE",
+                                       xen_cpu_up_prepare, xen_cpu_dead);
+        if (rc >= 0) {
+                rc = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
+                                               "XEN_HVM_GUEST_ONLINE",
+                                               xen_cpu_up_online, NULL);
+                if (rc < 0)
+                        cpuhp_remove_state_nocalls(CPUHP_XEN_PREPARE);
+        }
+
+        return rc >= 0 ? 0 : rc;
+}
+
 /* First C function to be called on Xen boot */
 asmlinkage __visible void __init xen_start_kernel(void)
 {
@@ -1629,7 +1649,7 @@ asmlinkage __visible void __init xen_start_kernel(void)
         xen_initial_gdt = &per_cpu(gdt_page, 0);
 
         xen_smp_init();
-        register_cpu_notifier(&xen_cpu_notifier);
+        WARN_ON(xen_cpuhp_setup());
 
 #ifdef CONFIG_ACPI_NUMA
         /*
@@ -1823,63 +1843,58 @@ static void __init init_hvm_pv_info(void)
         xen_domain_type = XEN_HVM_DOMAIN;
 }
 
-static int xen_cpu_notify(struct notifier_block *self, unsigned long action,
-                         void *hcpu)
+static int xen_cpu_up_prepare(unsigned int cpu)
 {
-        int cpu = (long)hcpu;
         int rc;
 
-        switch (action) {
-        case CPU_UP_PREPARE:
-                if (xen_hvm_domain()) {
-                        /*
-                         * This can happen if CPU was offlined earlier and
-                         * offlining timed out in common_cpu_die().
-                         */
-                        if (cpu_report_state(cpu) == CPU_DEAD_FROZEN) {
-                                xen_smp_intr_free(cpu);
-                                xen_uninit_lock_cpu(cpu);
-                        }
-
-                        if (cpu_acpi_id(cpu) != U32_MAX)
-                                per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu);
-                        else
-                                per_cpu(xen_vcpu_id, cpu) = cpu;
-                        xen_vcpu_setup(cpu);
+        if (xen_hvm_domain()) {
+                /*
+                 * This can happen if CPU was offlined earlier and
+                 * offlining timed out in common_cpu_die().
+                 */
+                if (cpu_report_state(cpu) == CPU_DEAD_FROZEN) {
+                        xen_smp_intr_free(cpu);
+                        xen_uninit_lock_cpu(cpu);
                 }
 
-                if (xen_pv_domain() ||
-                    (xen_have_vector_callback &&
-                     xen_feature(XENFEAT_hvm_safe_pvclock)))
-                        xen_setup_timer(cpu);
+                if (cpu_acpi_id(cpu) != U32_MAX)
+                        per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu);
+                else
+                        per_cpu(xen_vcpu_id, cpu) = cpu;
+                xen_vcpu_setup(cpu);
+        }
 
-                rc = xen_smp_intr_init(cpu);
-                if (rc) {
-                        WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
-                             cpu, rc);
-                        return NOTIFY_BAD;
-                }
+        if (xen_pv_domain() ||
+            (xen_have_vector_callback &&
+             xen_feature(XENFEAT_hvm_safe_pvclock)))
+                xen_setup_timer(cpu);
 
-                break;
-        case CPU_ONLINE:
-                xen_init_lock_cpu(cpu);
-                break;
-        case CPU_UP_CANCELED:
-                xen_smp_intr_free(cpu);
-                if (xen_pv_domain() ||
-                    (xen_have_vector_callback &&
-                     xen_feature(XENFEAT_hvm_safe_pvclock)))
-                        xen_teardown_timer(cpu);
-                break;
-        default:
-                break;
+        rc = xen_smp_intr_init(cpu);
+        if (rc) {
+                WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
+                     cpu, rc);
+                return rc;
         }
-        return NOTIFY_OK;
+        return 0;
 }
 
-static struct notifier_block xen_cpu_notifier = {
-        .notifier_call  = xen_cpu_notify,
-};
+static int xen_cpu_dead(unsigned int cpu)
+{
+        xen_smp_intr_free(cpu);
+
+        if (xen_pv_domain() ||
+            (xen_have_vector_callback &&
+             xen_feature(XENFEAT_hvm_safe_pvclock)))
+                xen_teardown_timer(cpu);
+
+        return 0;
+}
+
+static int xen_cpu_up_online(unsigned int cpu)
+{
+        xen_init_lock_cpu(cpu);
+        return 0;
+}
 
 #ifdef CONFIG_KEXEC_CORE
 static void xen_hvm_shutdown(void)
@@ -1910,7 +1925,7 @@ static void __init xen_hvm_guest_init(void)
         if (xen_feature(XENFEAT_hvm_callback_vector))
                 xen_have_vector_callback = 1;
         xen_hvm_smp_init();
-        register_cpu_notifier(&xen_cpu_notifier);
+        WARN_ON(xen_cpuhp_setup());
         xen_unplug_emulated_devices();
         x86_init.irqs.intr_init = xen_init_IRQ;
         xen_hvm_init_time_ops();
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 242bf530edfc..33d352f3295d 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -21,6 +21,7 @@ enum cpuhp_state {
         CPUHP_X2APIC_PREPARE,
         CPUHP_SMPCFD_PREPARE,
         CPUHP_RCUTREE_PREP,
+        CPUHP_XEN_PREPARE,
         CPUHP_NOTIFY_PREPARE,
         CPUHP_TIMERS_DEAD,
         CPUHP_BRINGUP_CPU,