[v2,4/5] x86/vpt: only try to resume timers belonging to enabled devices
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Message ID 20200727170539.55798-5-roger.pau@citrix.com
State New
Headers show
Series
  • x86_ virtual timer related fixes
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Commit Message

Roger Pau Monné July 27, 2020, 5:05 p.m. UTC
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@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
---
 xen/arch/x86/hvm/vpt.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

Patch
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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 )