KVM: local APIC TPR access reporting facility
Add a facility to report on accesses to the local apic tpr even if the
local apic is emulated in the kernel. This is basically a hack that
allows userspace to patch Windows which tends to bang on the tpr a lot.
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 4076331..50c3f3a 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -551,6 +551,23 @@
return tmcct;
}
+static void __report_tpr_access(struct kvm_lapic *apic, bool write)
+{
+ struct kvm_vcpu *vcpu = apic->vcpu;
+ struct kvm_run *run = vcpu->run;
+
+ set_bit(KVM_REQ_REPORT_TPR_ACCESS, &vcpu->requests);
+ kvm_x86_ops->cache_regs(vcpu);
+ run->tpr_access.rip = vcpu->arch.rip;
+ run->tpr_access.is_write = write;
+}
+
+static inline void report_tpr_access(struct kvm_lapic *apic, bool write)
+{
+ if (apic->vcpu->arch.tpr_access_reporting)
+ __report_tpr_access(apic, write);
+}
+
static u32 __apic_read(struct kvm_lapic *apic, unsigned int offset)
{
u32 val = 0;
@@ -568,6 +585,9 @@
val = apic_get_tmcct(apic);
break;
+ case APIC_TASKPRI:
+ report_tpr_access(apic, false);
+ /* fall thru */
default:
apic_update_ppr(apic);
val = apic_get_reg(apic, offset);
@@ -677,6 +697,7 @@
break;
case APIC_TASKPRI:
+ report_tpr_access(apic, true);
apic_set_tpr(apic, val & 0xff);
break;