Index: sys/dev/xen/debug/debug.c
===================================================================
--- sys/dev/xen/debug/debug.c
+++ sys/dev/xen/debug/debug.c
@@ -81,7 +81,8 @@
 
 	mtx_lock_spin(&lock);
 	sbuf_clear(buf);
-	xc_printf("Printing stack trace vCPU%d\n", PCPU_GET(vcpu_id));
+	xc_printf("Printing stack trace vCPU%d\n",
+		  cpu_to_vcpu_id(PCPU_GET(cpuid)));
 	stack_sbuf_print_ddb(buf, &st);
 	sbuf_finish(buf);
 	mtx_unlock_spin(&lock);
Index: sys/x86/include/xen/xen-os.h
===================================================================
--- sys/x86/include/xen/xen-os.h
+++ sys/x86/include/xen/xen-os.h
@@ -36,12 +36,21 @@
 /* Everything below this point is not included by assembler (.S) files. */
 #ifndef __ASSEMBLY__
 
+#include <sys/pcpu.h>
+
 /* If non-zero, the hypervisor has been configured to use a direct vector */
 extern int xen_vector_callback_enabled;
 
 /* tunable for disabling PV disks */
 extern int xen_disable_pv_disks;
 
+static inline u_int
+cpu_to_vcpu_id(u_int cpuid)
+{
+
+	return (pcpu_find(cpuid)->pc_vcpu_id);
+}
+
 static inline bool
 xen_support_evtchn_rebind(void)
 {