xen/x86: Move irq allocation from Xen smp_op.cpu_up()

Commit ce0d3c0a6fb1 ("genirq: Revert sparse irq locking around
__cpu_up() and move it to x86 for now") reverted irq locking
introduced by commit a89941816726 ("hotplug: Prevent alloc/free
of irq descriptors during cpu up/down") because of Xen allocating
irqs in both of its cpu_up ops.

We can move those allocations into CPU notifiers so that original
patch can be reinstated.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

1 files changed, 48 insertions, 13 deletions

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 8ffb089b19a5..c7f6b1f90efa 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -140,6 +140,8 @@ 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;
+
 /*
  * Point at some empty memory to start with. We map the real shared_info
  * page as soon as fixmap is up and running.
@@ -1627,6 +1629,7 @@ 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);
 
 #ifdef CONFIG_ACPI_NUMA
         /*
@@ -1820,21 +1823,53 @@ static void __init init_hvm_pv_info(void)
         xen_domain_type = XEN_HVM_DOMAIN;
 }
 
-static int xen_hvm_cpu_notify(struct notifier_block *self, unsigned long action,
-                              void *hcpu)
+static int xen_cpu_notify(struct notifier_block *self, unsigned long action,
+                         void *hcpu)
 {
         int cpu = (long)hcpu;
+        int rc;
+
         switch (action) {
         case CPU_UP_PREPARE:
-                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_have_vector_callback) {
-                        if (xen_feature(XENFEAT_hvm_safe_pvclock))
-                                xen_setup_timer(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 (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_pv_domain() ||
+                    (xen_have_vector_callback &&
+                     xen_feature(XENFEAT_hvm_safe_pvclock)))
+                        xen_setup_timer(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;
+                }
+
+                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;
@@ -1842,8 +1877,8 @@ static int xen_hvm_cpu_notify(struct notifier_block *self, unsigned long action,
         return NOTIFY_OK;
 }
 
-static struct notifier_block xen_hvm_cpu_notifier = {
-        .notifier_call  = xen_hvm_cpu_notify,
+static struct notifier_block xen_cpu_notifier = {
+        .notifier_call  = xen_cpu_notify,
 };
 
 #ifdef CONFIG_KEXEC_CORE
@@ -1875,7 +1910,7 @@ 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_hvm_cpu_notifier);
+        register_cpu_notifier(&xen_cpu_notifier);
         xen_unplug_emulated_devices();
         x86_init.irqs.intr_init = xen_init_IRQ;
         xen_hvm_init_time_ops();