xen/x86: Move freeze/thaw_domains to common code

The freeze_domains and thaw_domains functions are currently defined
in x86-specific suspend code. These functions are also useful on other
architectures, such as ARM, for implementing system-wide suspend and
resume functionality.

This patch moves these functions to common code so they can be reused
across architectures.

Signed-off-by: Mirela Simonovic <mirela.simonovic@aggios.com>
Signed-off-by: Saeed Nowshadi <saeed.nowshadi@xilinx.com>
Signed-off-by: Mykyta Poturai <mykyta_poturai@epam.com>
Signed-off-by: Mykola Kvach <mykola_kvach@epam.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

xen/arch/x86/acpi/power.c

@@ -138,31 +138,6 @@ static void device_power_up(enum dev_power_saved saved)
     }
 }
 
-static void freeze_domains(void)
-{
-    struct domain *d;
-
-    rcu_read_lock(&domlist_read_lock);
-    /*
-     * Note that we iterate in order of domain-id. Hence we will pause dom0
-     * first which is required for correctness (as only dom0 can add domains to
-     * the domain list). Otherwise we could miss concurrently-created domains.
-     */
-    for_each_domain ( d )
-        domain_pause(d);
-    rcu_read_unlock(&domlist_read_lock);
-}
-
-static void thaw_domains(void)
-{
-    struct domain *d;
-
-    rcu_read_lock(&domlist_read_lock);
-    for_each_domain ( d )
-        domain_unpause(d);
-    rcu_read_unlock(&domlist_read_lock);
-}
-
 static void acpi_sleep_prepare(u32 state)
 {
     void *wakeup_vector_va;

xen/common/domain.c

@@ -2405,6 +2405,31 @@ domid_t get_initial_domain_id(void)
     return hardware_domid;
 }
 
+void freeze_domains(void)
+{
+    struct domain *d;
+
+    rcu_read_lock(&domlist_read_lock);
+    /*
+     * Note that we iterate in order of domain-id. Hence we will pause dom0
+     * first which is required for correctness (as only dom0 can add domains to
+     * the domain list). Otherwise we could miss concurrently-created domains.
+     */
+    for_each_domain ( d )
+        domain_pause(d);
+    rcu_read_unlock(&domlist_read_lock);
+}
+
+void thaw_domains(void)
+{
+    struct domain *d;
+
+    rcu_read_lock(&domlist_read_lock);
+    for_each_domain ( d )
+        domain_unpause(d);
+    rcu_read_unlock(&domlist_read_lock);
+}
+
 /*
  * Local variables:
  * mode: C

xen/include/xen/sched.h

@@ -1070,6 +1070,9 @@ static inline struct vcpu *domain_vcpu(const struct domain *d,
     return vcpu_id >= d->max_vcpus ? NULL : d->vcpu[idx];
 }
 
+void freeze_domains(void);
+void thaw_domains(void);
+
 void cpu_init(void);
 
 /*