diff --git a/usr.sbin/bhyve/aarch64/bhyve_machdep.h b/usr.sbin/bhyve/aarch64/bhyve_machdep.h
--- a/usr.sbin/bhyve/aarch64/bhyve_machdep.h
+++ b/usr.sbin/bhyve/aarch64/bhyve_machdep.h
@@ -7,6 +7,7 @@
 #ifndef _BHYVE_MACHDEP_H_
 #define	_BHYVE_MACHDEP_H_
 
+extern uint64_t *cpu_to_mpidr;
 extern cpuset_t running_cpumask;
 
 #endif /* _BHYVE_MACHDEP_H_ */
diff --git a/usr.sbin/bhyve/aarch64/bhyverun_machdep.c b/usr.sbin/bhyve/aarch64/bhyverun_machdep.c
--- a/usr.sbin/bhyve/aarch64/bhyverun_machdep.c
+++ b/usr.sbin/bhyve/aarch64/bhyverun_machdep.c
@@ -30,6 +30,8 @@
 #include <sys/mman.h>
 #include <sys/stat.h>
 
+#include <machine/armreg.h>
+
 #include <assert.h>
 #include <err.h>
 #include <errno.h>
@@ -74,6 +76,8 @@
 #define	PCIE_INTC	36
 #define	PCIE_INTD	37
 
+uint64_t *cpu_to_mpidr;
+
 void
 bhyve_init_config(void)
 {
@@ -364,6 +368,23 @@
 	int error;
 	int pcie_intrs[4] = {PCIE_INTA, PCIE_INTB, PCIE_INTC, PCIE_INTD};
 
+	cpu_to_mpidr = calloc(guest_ncpus, sizeof(*cpu_to_mpidr));
+	if (cpu_to_mpidr == NULL) {
+		warnx("unable to allocate space for mpidr list");
+		return (ENOMEM);
+	}
+
+	for (uint64_t cpu = 0; cpu < (uint64_t)guest_ncpus; cpu++) {
+		uint64_t mpidr;
+
+		error = vm_get_register(fbsdrun_vcpu(cpu), VM_REG_GUEST_MPIDR_EL1,
+		    &mpidr);
+		assert(error == 0);
+#define	MPIDR_AFF_MASK	(MPIDR_AFF0_MASK | MPIDR_AFF1_MASK | MPIDR_AFF2_MASK | MPIDR_AFF3_MASK)
+		cpu_to_mpidr[cpu] = mpidr & MPIDR_AFF_MASK;
+#undef MPIDR_AFF_MASK
+	}
+
 	bootrom = get_config_value("bootrom");
 	if (bootrom == NULL) {
 		warnx("no bootrom specified");
diff --git a/usr.sbin/bhyve/aarch64/fdt.c b/usr.sbin/bhyve/aarch64/fdt.c
--- a/usr.sbin/bhyve/aarch64/fdt.c
+++ b/usr.sbin/bhyve/aarch64/fdt.c
@@ -39,6 +39,7 @@
 #include <vmmapi.h>
 
 #include "config.h"
+#include "bhyve_machdep.h"
 #include "bhyverun.h"
 #include "fdt.h"
 
@@ -92,7 +93,7 @@
 	fdt_begin_node(fdt, node_name);
 	fdt_property_string(fdt, "device_type", "cpu");
 	fdt_property_string(fdt, "compatible", "arm,armv8");
-	fdt_property_u64(fdt, "reg", cpuid);
+	fdt_property_u64(fdt, "reg", cpu_to_mpidr[cpuid]);
 	fdt_property_string(fdt, "enable-method", "psci");
 	fdt_end_node(fdt);
 }
diff --git a/usr.sbin/bhyve/aarch64/vmexit.c b/usr.sbin/bhyve/aarch64/vmexit.c
--- a/usr.sbin/bhyve/aarch64/vmexit.c
+++ b/usr.sbin/bhyve/aarch64/vmexit.c
@@ -152,7 +152,7 @@
 static uint64_t
 smccc_affinity_info(uint64_t target_affinity, uint32_t lowest_affinity_level)
 {
-	uint64_t cpu_aff, mask = 0;
+	uint64_t mask = 0;
 
 	switch (lowest_affinity_level) {
 	case 0:
@@ -172,13 +172,7 @@
 	}
 
 	for (int vcpu = 0; vcpu < guest_ncpus; vcpu++) {
-		/* TODO: We should get this from the kernel */
-		cpu_aff = (vcpu & 0xf) << MPIDR_AFF0_SHIFT |
-		    ((vcpu >> 4) & 0xff) << MPIDR_AFF1_SHIFT |
-		    ((vcpu >> 12) & 0xff) << MPIDR_AFF2_SHIFT |
-		    (uint64_t)((vcpu >> 20) & 0xff) << MPIDR_AFF3_SHIFT;
-
-		if ((cpu_aff & mask) == (target_affinity & mask) &&
+		if ((cpu_to_mpidr[vcpu] & mask) == (target_affinity & mask) &&
 		    CPU_ISSET(vcpu, &running_cpumask)) {
 			/* Return ON if any CPUs are on */
 			return (PSCI_AFFINITY_INFO_ON);
@@ -194,9 +188,9 @@
 {
 	struct vcpu *newvcpu;
 	struct vm_exit *vme;
-	uint64_t newcpu, smccc_rv;
+	uint64_t mpidr, smccc_rv;
 	enum vm_suspend_how how;
-	int error;
+	int error, newcpu;
 
 	/* Return the Unknown Function Identifier  by default */
 	smccc_rv = SMCCC_RET_NOT_SUPPORTED;
@@ -211,8 +205,13 @@
 	case PSCI_FNID_CPU_OFF:
 		break;
 	case PSCI_FNID_CPU_ON:
-		newcpu = vme->u.smccc_call.args[0];
-		if (newcpu > (uint64_t)guest_ncpus) {
+		mpidr = vme->u.smccc_call.args[0];
+		for (newcpu = 0; newcpu < guest_ncpus; newcpu++) {
+			if (cpu_to_mpidr[newcpu] == mpidr)
+				break;
+		}
+
+		if (newcpu == guest_ncpus) {
 			smccc_rv = PSCI_RETVAL_INVALID_PARAMS;
 			break;
 		}