diff --git a/sys/arm64/include/hypervisor.h b/sys/arm64/include/hypervisor.h
--- a/sys/arm64/include/hypervisor.h
+++ b/sys/arm64/include/hypervisor.h
@@ -232,4 +232,22 @@
 /* Assumed to be 0 by locore.S */
 #define	VTTBR_HOST		0x0000000000000000
 
+/* MDCR_EL2 - Hyp Debug Control Register */
+#define	MDCR_EL2_HPMN_MASK	0x1f
+#define	MDCR_EL2_HPMN_SHIFT	0
+#define	MDCR_EL2_TPMCR_SHIFT	5
+#define	MDCR_EL2_TPMCR		(0x1UL << MDCR_EL2_TPMCR_SHIFT)
+#define	MDCR_EL2_TPM_SHIFT	6
+#define	MDCR_EL2_TPM		(0x1UL << MDCR_EL2_TPM_SHIFT)
+#define	MDCR_EL2_HPME_SHIFT	7
+#define	MDCR_EL2_HPME		(0x1UL << MDCR_EL2_HPME_SHIFT)
+#define	MDCR_EL2_TDE_SHIFT	8
+#define	MDCR_EL2_TDE		(0x1UL << MDCR_EL2_TDE_SHIFT)
+#define	MDCR_EL2_TDA_SHIFT	9
+#define	MDCR_EL2_TDA		(0x1UL << MDCR_EL2_TDA_SHIFT)
+#define	MDCR_EL2_TDOSA_SHIFT	10
+#define	MDCR_EL2_TDOSA		(0x1UL << MDCR_EL2_TDOSA_SHIFT)
+#define	MDCR_EL2_TDRA_SHIFT	11
+#define	MDCR_EL2_TDRA		(0x1UL << MDCR_EL2_TDRA_SHIFT)
+
 #endif /* !_MACHINE_HYPERVISOR_H_ */