x86:vlapic: Fix possible guest tick losing after save/restore

Guest vcpu may totally lose all ticks if the vlapic->pt.irq was not
restored during save/restore process. Fix it.

Signed-off-by: Wei Gang <gang.wei@intel.com>

diff --git a/xen/arch/x86/hvm/vlapic.c b/xen/arch/x86/hvm/vlapic.c
index 483588a99b6a41d93b5302f3312ae30215cd0032..cf0ee2108148296c4d0ecc38caba5c45aa8c8bc0 100644 (file)
--- a/xen/arch/x86/hvm/vlapic.c
+++ b/xen/arch/x86/hvm/vlapic.c
@@ -955,12 +955,12 @@ static void lapic_rearm(struct vlapic *s)
     unsigned long tmict = vlapic_get_reg(s, APIC_TMICT);
     uint64_t period;
 
+    s->pt.irq = vlapic_get_reg(s, APIC_LVTT) & APIC_VECTOR_MASK;
     if ( (tmict = vlapic_get_reg(s, APIC_TMICT)) == 0 )
         return;
 
     period = ((uint64_t)APIC_BUS_CYCLE_NS *
               (uint32_t)tmict * s->hw.timer_divisor);
-    s->pt.irq = vlapic_get_reg(s, APIC_LVTT) & APIC_VECTOR_MASK;
     create_periodic_time(vlapic_vcpu(s), &s->pt, period,
                          vlapic_lvtt_period(s) ? period : 0,
                          s->pt.irq,