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;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 513258c..c2b8088 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -684,6 +684,7 @@
case KVM_CAP_USER_MEMORY:
case KVM_CAP_SET_TSS_ADDR:
case KVM_CAP_EXT_CPUID:
+ case KVM_CAP_VAPIC:
r = 1;
break;
default:
@@ -1055,6 +1056,15 @@
return 0;
}
+static int vcpu_ioctl_tpr_access_reporting(struct kvm_vcpu *vcpu,
+ struct kvm_tpr_access_ctl *tac)
+{
+ if (tac->flags)
+ return -EINVAL;
+ vcpu->arch.tpr_access_reporting = !!tac->enabled;
+ return 0;
+}
+
long kvm_arch_vcpu_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
@@ -1148,6 +1158,21 @@
case KVM_SET_MSRS:
r = msr_io(vcpu, argp, do_set_msr, 0);
break;
+ case KVM_TPR_ACCESS_REPORTING: {
+ struct kvm_tpr_access_ctl tac;
+
+ r = -EFAULT;
+ if (copy_from_user(&tac, argp, sizeof tac))
+ goto out;
+ r = vcpu_ioctl_tpr_access_reporting(vcpu, &tac);
+ if (r)
+ goto out;
+ r = -EFAULT;
+ if (copy_to_user(argp, &tac, sizeof tac))
+ goto out;
+ r = 0;
+ break;
+ };
default:
r = -EINVAL;
}