[Xen-devel] [PATCH 11/12] Allow vcpu to pause self

["Tian, Kevin" <kevin.tian@xxxxxxxxx>]

Allow one vcpu to pause self, with full context sync-ed.

Signed-off-by Kevin Tian <kevin.tian@xxxxxxxxx>

diff -r f6443af464be xen/common/domain.c
--- a/xen/common/domain.c       Tue Feb 13 13:37:12 2007 +0800
+++ b/xen/common/domain.c       Tue Feb 13 13:41:44 2007 +0800
@@ -375,6 +375,18 @@ void vcpu_pause_nosync(struct vcpu *v)
     vcpu_sleep_nosync(v);
 }
 
+/* This is not a code path called from guest, since execution is paused
+ * after next context switch. ACPI PM requires this to pause vcpu0 of
+ * dom0 itself, in case that vcpu not running on cpu 0.
+ */
+void vcpu_pause_self(void)
+{
+    struct vcpu *v = current;
+
+    set_bit(_VCPUF_need_sync, &v->vcpu_flags);
+    vcpu_pause_nosync(v);
+}
+
 void vcpu_unpause(struct vcpu *v)
 {
     int wake;
diff -r f6443af464be xen/common/schedule.c
--- a/xen/common/schedule.c     Tue Feb 13 13:37:12 2007 +0800
+++ b/xen/common/schedule.c     Tue Feb 13 13:41:44 2007 +0800
@@ -629,6 +629,13 @@ void context_saved(struct vcpu *prev)
 
     if ( unlikely(test_bit(_VCPUF_migrating, &prev->vcpu_flags)) )
         vcpu_migrate(prev);
+
+    if ( unlikely(test_bit(_VCPUF_need_sync, &prev->vcpu_flags)) )
+    {
+        sync_vcpu_execstate(prev);
+        /* test and clear can be split, since here is the only clear
point */
+        clear_bit(_VCPUF_need_sync, &prev->vcpu_flags);
+    }
 }
 
 
/***********************************************************************
*****
diff -r f6443af464be xen/include/xen/sched.h
--- a/xen/include/xen/sched.h   Tue Feb 13 13:37:12 2007 +0800
+++ b/xen/include/xen/sched.h   Tue Feb 13 13:41:44 2007 +0800
@@ -423,6 +423,9 @@ extern struct domain *domain_list;
  /* VCPU affinity has changed: migrating to a new CPU. */
 #define _VCPUF_migrating       13
 #define VCPUF_migrating        (1UL<<_VCPUF_migrating)
+ /* VCPU needs full context sync once switched out */
+#define _VCPUF_need_sync       14
+#define VCPUF_need_sync        (1UL<<_VCPUF_need_sync)
 
 /*
  * Per-domain flags (domain_flags).
@@ -465,6 +468,7 @@ static inline int vcpu_runnable(struct v
 
 void vcpu_pause(struct vcpu *v);
 void vcpu_pause_nosync(struct vcpu *v);
+void vcpu_pause_self(void);
 void domain_pause(struct domain *d);
 void vcpu_unpause(struct vcpu *v);
 void domain_unpause(struct domain *d);

Attachment: vcpu_pause_self.patch
Description: vcpu_pause_self.patch

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