Allow domains to set a shutdown code without actually shutting down

Useful for Windows guests, since the PV drivers are notified that
the domain is about to crash just before the crash dump gets written.

Signed-off-by: Tim Deegan <Tim.Deegan@citrix.com>
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>

diff --git a/xen/common/domain.c b/xen/common/domain.c
index f8d8a25346da2be82dc5521eb25903c676fe87a6..c7928f94d6947da0022e215efaa33b023db8104e 100644 (file)
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -228,11 +228,13 @@ struct domain *domain_create(
     atomic_set(&d->refcnt, 1);
     spin_lock_init_prof(d, domain_lock);
     spin_lock_init_prof(d, page_alloc_lock);
-    spin_lock_init(&d->shutdown_lock);
     spin_lock_init(&d->hypercall_deadlock_mutex);
     INIT_PAGE_LIST_HEAD(&d->page_list);
     INIT_PAGE_LIST_HEAD(&d->xenpage_list);
 
+    spin_lock_init(&d->shutdown_lock);
+    d->shutdown_code = -1;
+
     if ( domcr_flags & DOMCRF_hvm )
         d->is_hvm = 1;
 
@@ -485,11 +487,15 @@ void domain_shutdown(struct domain *d, u8 reason)
 {
     struct vcpu *v;
 
+    spin_lock(&d->shutdown_lock);
+
+    if ( d->shutdown_code == -1 )
+        d->shutdown_code = reason;
+    reason = d->shutdown_code;
+
     if ( d->domain_id == 0 )
         dom0_shutdown(reason);
 
-    spin_lock(&d->shutdown_lock);
-
     if ( d->is_shutting_down )
     {
         spin_unlock(&d->shutdown_lock);
@@ -497,7 +503,6 @@ void domain_shutdown(struct domain *d, u8 reason)
     }
 
     d->is_shutting_down = 1;
-    d->shutdown_code = reason;
 
     smp_mb(); /* set shutdown status /then/ check for per-cpu deferrals */
 
@@ -529,6 +534,7 @@ void domain_resume(struct domain *d)
     spin_lock(&d->shutdown_lock);
 
     d->is_shutting_down = d->is_shut_down = 0;
+    d->shutdown_code = -1;
 
     for_each_vcpu ( d, v )
     {

diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index 01651b3d3b6ef0f0ac28d82286ed67e6852aa1d0..655dbd034ca6000456eda2ace60892c710e952d3 100644 (file)
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -704,6 +704,27 @@ ret_t do_sched_op(int cmd, XEN_GUEST_HANDLE(void) arg)
         break;
     }
 
+    case SCHEDOP_shutdown_code:
+    {
+        struct sched_shutdown sched_shutdown;
+        struct domain *d = current->domain;
+
+        ret = -EFAULT;
+        if ( copy_from_guest(&sched_shutdown, arg, 1) )
+            break;
+
+        TRACE_3D(TRC_SCHED_SHUTDOWN_CODE,
+                 d->domain_id, current->vcpu_id, sched_shutdown.reason);
+
+        spin_lock(&d->shutdown_lock);
+        if ( d->shutdown_code == -1 )
+            d->shutdown_code = (u8)sched_shutdown.reason;
+        spin_unlock(&d->shutdown_lock);
+
+        ret = 0;
+        break;
+    }
+
     case SCHEDOP_poll:
     {
         struct sched_poll sched_poll;

diff --git a/xen/include/public/sched.h b/xen/include/public/sched.h
index 2227a95be625697da21fe54aeaf2c9b574094a7d..e498c3c501811c905eaeec38850340ad793fcf3d 100644 (file)
--- a/xen/include/public/sched.h
+++ b/xen/include/public/sched.h
@@ -98,6 +98,13 @@ struct sched_remote_shutdown {
 typedef struct sched_remote_shutdown sched_remote_shutdown_t;
 DEFINE_XEN_GUEST_HANDLE(sched_remote_shutdown_t);
 
+/*
+ * Latch a shutdown code, so that when the domain later shuts down it
+ * reports this code to the control tools.
+ * @arg == as for SCHEDOP_shutdown.
+ */
+#define SCHEDOP_shutdown_code 5
+
 /*
  * Reason codes for SCHEDOP_shutdown. These may be interpreted by control
  * software to determine the appropriate action. For the most part, Xen does

diff --git a/xen/include/public/trace.h b/xen/include/public/trace.h
index 0a8f1adfa3cd87e456f8a2d44493d5ab60f1bea1..c762c1858a5504d026010173ab6d75cee0aeb20c 100644 (file)
--- a/xen/include/public/trace.h
+++ b/xen/include/public/trace.h
@@ -79,6 +79,7 @@
 #define TRC_SCHED_DOM_TIMER_FN   (TRC_SCHED_VERBOSE + 13)
 #define TRC_SCHED_SWITCH_INFPREV (TRC_SCHED_VERBOSE + 14)
 #define TRC_SCHED_SWITCH_INFNEXT (TRC_SCHED_VERBOSE + 15)
+#define TRC_SCHED_SHUTDOWN_CODE  (TRC_SCHED_VERBOSE + 16)
 
 #define TRC_MEM_PAGE_GRANT_MAP      (TRC_MEM + 1)
 #define TRC_MEM_PAGE_GRANT_UNMAP    (TRC_MEM + 2)