Index: usr.sbin/bhyve/riscv/vmexit.c
===================================================================
--- usr.sbin/bhyve/riscv/vmexit.c
+++ usr.sbin/bhyve/riscv/vmexit.c
@@ -47,6 +47,7 @@
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <unistd.h>
 
 #include <vmmapi.h>
 
@@ -135,6 +136,12 @@
     struct vm_run *vmrun __unused)
 {
 
+	/*
+	 * XXX-MJ sleep for a short period to avoid chewing up the CPU in the
+	 * window between activation of the vCPU thread and the
+	 * SBI_HSM_HART_START request.
+	 */
+	usleep(1000);
 	return (VMEXIT_CONTINUE);
 }