[Xen-devel] [PATCH v5 1/9] vm_event: clear up return value of vm_event_monitor_traps

[Tamas K Lengyel <tamas@xxxxxxxxxxxxx>]

The return value has not been clearly defined, with the function
never returning 0 which seemingly indicated a condition where the
guest should crash. In this patch we define -rc as error condition
where the notification was not sent, 0 where the notification was sent
and the vCPU is not paused and 1 that the notification was sent and
that the vCPU is paused.

Signed-off-by: Tamas K Lengyel <tamas@xxxxxxxxxxxxx>
---
Cc: Jun Nakajima <jun.nakajima@xxxxxxxxx>
Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>
---
 xen/arch/x86/hvm/event.c   | 4 ++--
 xen/arch/x86/hvm/vmx/vmx.c | 6 +++---
 xen/common/vm_event.c      | 5 +++--
 3 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/xen/arch/x86/hvm/event.c b/xen/arch/x86/hvm/event.c
index 56c5514..5772c6b 100644
--- a/xen/arch/x86/hvm/event.c
+++ b/xen/arch/x86/hvm/event.c
@@ -47,8 +47,8 @@ bool_t hvm_event_cr(unsigned int index, unsigned long value, 
unsigned long old)
             .u.write_ctrlreg.old_value = old
         };
 
-        vm_event_monitor_traps(curr, sync, &req);
-        return 1;
+        if ( vm_event_monitor_traps(curr, sync, &req) >= 0 )
+            return 1;
     }
 
     return 0;
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 3acf1ab..097d97c 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -3392,11 +3392,11 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
                 break;
             }
             else {
-                int handled =
+                int rc =
                         hvm_event_breakpoint(regs->eip,
                                              HVM_EVENT_SOFTWARE_BREAKPOINT);
 
-                if ( handled < 0 ) 
+                if ( !rc )
                 {
                     struct hvm_trap trap = {
                         .vector = TRAP_int3,
@@ -3410,7 +3410,7 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
                     hvm_inject_trap(&trap);
                     break;
                 }
-                else if ( handled )
+                else if ( rc > 0 )
                     break;
             }
 
diff --git a/xen/common/vm_event.c b/xen/common/vm_event.c
index 2906407..fe86fb9 100644
--- a/xen/common/vm_event.c
+++ b/xen/common/vm_event.c
@@ -801,7 +801,7 @@ int vm_event_monitor_traps(struct vcpu *v, uint8_t sync,
          * If there was no ring to handle the event, then
          * simply continue executing normally.
          */
-        return 1;
+        return 0;
     default:
         return rc;
     };
@@ -810,6 +810,7 @@ int vm_event_monitor_traps(struct vcpu *v, uint8_t sync,
     {
         req->flags |= VM_EVENT_FLAG_VCPU_PAUSED;
         vm_event_vcpu_pause(v);
+        rc = 1;
     }
 
     if ( altp2m_active(d) )
@@ -821,7 +822,7 @@ int vm_event_monitor_traps(struct vcpu *v, uint8_t sync,
     vm_event_fill_regs(req);
     vm_event_put_request(d, &d->vm_event->monitor, req);
 
-    return 1;
+    return rc;
 }
 
 void vm_event_monitor_guest_request(void)
-- 
2.8.1


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel