[xen master] x86/vpt: only try to resume timers belonging to enabled devices

[patchbot@xxxxxxx]

commit b9e9ccbb11e4c54b498d3a08e48347c3cad72944
Author:     Roger Pau Monne <roger.pau@xxxxxxxxxx>
AuthorDate: Mon Jul 27 19:05:38 2020 +0200
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Tue Jul 28 19:33:28 2020 +0100

    x86/vpt: only try to resume timers belonging to enabled devices
    
    Check whether the emulated device is actually enabled before trying to
    resume the associated timers.
    
    Thankfully all those structures are zeroed at initialization, and
    since the devices are not enabled they are never populated, which
    triggers the pt->vcpu check at the beginning of pt_resume forcing an
    exit from the function.
    
    While there limit the scope of i and make it unsigned.
    
    Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/hvm/vpt.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/xen/arch/x86/hvm/vpt.c b/xen/arch/x86/hvm/vpt.c
index 47f2c2aa64..62c87867c5 100644
--- a/xen/arch/x86/hvm/vpt.c
+++ b/xen/arch/x86/hvm/vpt.c
@@ -636,14 +636,19 @@ static void pt_resume(struct periodic_time *pt)
 
 void pt_may_unmask_irq(struct domain *d, struct periodic_time *vlapic_pt)
 {
-    int i;
-
     if ( d )
     {
-        pt_resume(&d->arch.vpit.pt0);
-        pt_resume(&d->arch.hvm.pl_time->vrtc.pt);
-        for ( i = 0; i < HPET_TIMER_NUM; i++ )
-            pt_resume(&d->arch.hvm.pl_time->vhpet.pt[i]);
+        if ( has_vpit(d) )
+            pt_resume(&d->arch.vpit.pt0);
+        if ( has_vrtc(d) )
+            pt_resume(&d->arch.hvm.pl_time->vrtc.pt);
+        if ( has_vhpet(d) )
+        {
+            unsigned int i;
+
+            for ( i = 0; i < HPET_TIMER_NUM; i++ )
+                pt_resume(&d->arch.hvm.pl_time->vhpet.pt[i]);
+        }
     }
 
     if ( vlapic_pt )
--
generated by git-patchbot for /home/xen/git/xen.git#master