diff --git a/[refs] b/[refs]
index fb11b474e912..a94cb82376c7 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 9e40b67bf2bfaa40b28354c501a72fd001a1397a
+refs/heads/master: 5eadf916dfa04c3c51397dbcb803ce8735bf191a
diff --git a/trunk/arch/x86/kvm/lapic.h b/trunk/arch/x86/kvm/lapic.h
index 6f4ce2575d09..d29da25ea525 100644
--- a/trunk/arch/x86/kvm/lapic.h
+++ b/trunk/arch/x86/kvm/lapic.h
@@ -13,6 +13,11 @@ struct kvm_lapic {
 	u32 divide_count;
 	struct kvm_vcpu *vcpu;
 	bool irr_pending;
+	/**
+	 * APIC register page.  The layout matches the register layout seen by
+	 * the guest 1:1, because it is accessed by the vmx microcode.
+	 * Note: Only one register, the TPR, is used by the microcode.
+	 */
 	void *regs;
 	gpa_t vapic_addr;
 	struct page *vapic_page;