KVM: Don't update PPR on any APIC read
The current code will update the PPR on almost any APIC read; however
that's only required if we read the PPR.
kvm_update_ppr() shows up in some profiles, albeit with a low usage (~1%).
This should reduce it further (it will still be called during interrupt
processing).
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index fff7173..ad7fff7 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -696,12 +696,14 @@
val = apic_get_tmcct(apic);
break;
-
+ case APIC_PROCPRI:
+ apic_update_ppr(apic);
+ val = apic_get_reg(apic, offset);
+ break;
case APIC_TASKPRI:
report_tpr_access(apic, false);
/* fall thru */
default:
- apic_update_ppr(apic);
val = apic_get_reg(apic, offset);
break;
}