x86/S3: Restore broken vcpu affinity on resume

When in SYS_STATE_suspend, and going through the cpu_disable_scheduler
path, save a copy of the current cpu affinity, and mark a flag to
restore it later.

Later, in the resume process, when enabling nonboot cpus restore these
affinities.

Signed-off-by: Ben Guthro <benjamin.guthro@citrix.com>
Acked-by: George Dunlap <george.dunlap@eu.citrix.com>
Acked-by: Keir Fraser <keir@xen.org>
master commit: 41e71c2607e036f1ac00df898b8f4acb2d4df7ee
master date: 2013-04-02 09:52:32 +0200

3 files changed, 51 insertions, 3 deletions

diff --git a/xen/arch/x86/acpi/power.c b/xen/arch/x86/acpi/power.c
index 7a08091b00..dc37be88b5 100644
--- a/xen/arch/x86/acpi/power.c
+++ b/xen/arch/x86/acpi/power.c
@@ -96,7 +96,10 @@ static void thaw_domains(void)
 
     rcu_read_lock(&domlist_read_lock);
     for_each_domain ( d )
+    {
+        restore_vcpu_affinity(d);
         domain_unpause(d);
+    }
     rcu_read_unlock(&domlist_read_lock);
 }
 
diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index 001da3d03a..edb0177a59 100644
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -545,6 +545,38 @@ void vcpu_force_reschedule(struct vcpu *v)
     }
 }
 
+void restore_vcpu_affinity(struct domain *d)
+{
+    struct vcpu *v;
+
+    for_each_vcpu ( d, v )
+    {
+        vcpu_schedule_lock_irq(v);
+
+        if ( v->affinity_broken )
+        {
+            printk(XENLOG_DEBUG "Restoring affinity for d%dv%d\n",
+                   d->domain_id, v->vcpu_id);
+            cpus_copy(v->cpu_affinity, v->cpu_affinity_saved);
+            v->affinity_broken = 0;
+        }
+
+        if ( v->processor == smp_processor_id() )
+        {
+            set_bit(_VPF_migrating, &v->pause_flags);
+            vcpu_schedule_unlock_irq(v);
+            vcpu_sleep_nosync(v);
+            vcpu_migrate(v);
+        }
+        else
+        {
+            vcpu_schedule_unlock_irq(v);
+        }
+    }
+
+    domain_update_node_affinity(d);
+}
+
 /*
  * This function is used by cpu_hotplug code from stop_machine context
  * and from cpupools to switch schedulers on a cpu.
@@ -559,7 +591,7 @@ int cpu_disable_scheduler(unsigned int cpu)
     bool_t affinity_broken;
 
     c = per_cpu(cpupool, cpu);
-    if ( (c == NULL) || (system_state == SYS_STATE_suspend) )
+    if ( c == NULL )
         return ret;
 
     for_each_domain ( d )
@@ -577,8 +609,15 @@ int cpu_disable_scheduler(unsigned int cpu)
             if ( cpus_empty(online_affinity) &&
                  cpu_isset(cpu, v->cpu_affinity) )
             {
-                printk("Breaking vcpu affinity for domain %d vcpu %d\n",
-                        v->domain->domain_id, v->vcpu_id);
+                printk(XENLOG_DEBUG "Breaking affinity for d%dv%d\n",
+                        d->domain_id, v->vcpu_id);
+
+                if (system_state == SYS_STATE_suspend)
+                {
+                    cpus_copy(v->cpu_affinity_saved, v->cpu_affinity);
+                    v->affinity_broken = 1;
+                }
+
                 cpus_setall(v->cpu_affinity);
                 affinity_broken = 1;
             }
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 35c3a7f13c..5909d9ace7 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -143,6 +143,9 @@ struct vcpu
     bool_t           defer_shutdown;
     /* VCPU is paused following shutdown request (d->is_shutting_down)? */
     bool_t           paused_for_shutdown;
+    /* VCPU need affinity restored */
+    bool_t           affinity_broken;
+
 
     /*
      * > 0: a single port is being polled;
@@ -165,6 +168,8 @@ struct vcpu
     cpumask_t        cpu_affinity;
     /* Used to change affinity temporarily. */
     cpumask_t        cpu_affinity_tmp;
+    /* Used to restore affinity across S3. */
+    cpumask_t        cpu_affinity_saved;
 
     /* Bitmask of CPUs which are holding onto this VCPU's state. */
     cpumask_t        vcpu_dirty_cpumask;
@@ -619,6 +624,7 @@ int schedule_cpu_switch(unsigned int cpu, struct cpupool *c);
 void vcpu_force_reschedule(struct vcpu *v);
 int cpu_disable_scheduler(unsigned int cpu);
 int vcpu_set_affinity(struct vcpu *v, cpumask_t *affinity);
+void restore_vcpu_affinity(struct domain *d);
 
 void vcpu_runstate_get(struct vcpu *v, struct vcpu_runstate_info *runstate);
 uint64_t get_cpu_idle_time(unsigned int cpu);