[Xen-changelog] [xen master] x86: re-enable VCPUOP_register_vcpu_time_memory_area

[patchbot@xxxxxxx]

commit ae5092f420e87a4a6b541bf581378c8cc0ee3a99
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Mon May 27 08:59:38 2013 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon May 27 08:59:38 2013 +0200

    x86: re-enable VCPUOP_register_vcpu_time_memory_area
    
    By moving the call to update_vcpu_system_time() out of schedule() into
    arch-specific context switch code, the original problem of the function
    accessing the wrong domain's address space goes away (obvious even from
    patch context, as update_runstate_area() does similar copying).
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Keir Fraser <keir@xxxxxxx>
---
 xen/arch/arm/domain.c  |    3 +++
 xen/arch/x86/domain.c  |    9 +++------
 xen/arch/x86/hvm/hvm.c |    2 ++
 xen/common/schedule.c  |    2 --
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index ee12b5f..4c434a1 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -232,6 +232,9 @@ static void schedule_tail(struct vcpu *prev)
 
     if ( prev != current )
         update_runstate_area(current);
+
+    /* Ensure that the vcpu has an up-to-date time base. */
+    update_vcpu_system_time(current);
 }
 
 static void continue_new_vcpu(struct vcpu *prev)
diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index 161d1b3..5c89197 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -966,11 +966,6 @@ arch_do_vcpu_op(
 
     switch ( cmd )
     {
-    /*
-     * XXX Disable for 4.0.0: __update_vcpu_system_time() writes to the given
-     * virtual address even when running in another domain's address space.
-     */
-#if 0
     case VCPUOP_register_vcpu_time_memory_area:
     {
         struct vcpu_register_time_memory_area area;
@@ -989,7 +984,6 @@ arch_do_vcpu_op(
 
         break;
     }
-#endif
 
     case VCPUOP_get_physid:
     {
@@ -1457,6 +1451,9 @@ void context_switch(struct vcpu *prev, struct vcpu *next)
     if (prev != next)
         update_runstate_area(next);
 
+    /* Ensure that the vcpu has an up-to-date time base. */
+    update_vcpu_system_time(next);
+
     schedule_tail(next);
     BUG();
 }
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index bcf9609..a962ce2 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -3191,6 +3191,7 @@ static long hvm_vcpu_op(
     case VCPUOP_set_singleshot_timer:
     case VCPUOP_stop_singleshot_timer:
     case VCPUOP_register_vcpu_info:
+    case VCPUOP_register_vcpu_time_memory_area:
         rc = do_vcpu_op(cmd, vcpuid, arg);
         break;
     default:
@@ -3249,6 +3250,7 @@ static long hvm_vcpu_op_compat32(
     case VCPUOP_set_singleshot_timer:
     case VCPUOP_stop_singleshot_timer:
     case VCPUOP_register_vcpu_info:
+    case VCPUOP_register_vcpu_time_memory_area:
         rc = compat_vcpu_op(cmd, vcpuid, arg);
         break;
     default:
diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index e526602..a8398bd 100644
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -1231,8 +1231,6 @@ static void schedule(void)
     if ( next_slice.migrated )
         evtchn_move_pirqs(next);
 
-    /* Ensure that the domain has an up-to-date time base. */
-    update_vcpu_system_time(next);
     vcpu_periodic_timer_work(next);
 
     context_switch(prev, next);
--
generated by git-patchbot for /home/xen/git/xen.git#master

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