diff --git a/usr.sbin/bhyve/pci_uart.c b/usr.sbin/bhyve/pci_uart.c
--- a/usr.sbin/bhyve/pci_uart.c
+++ b/usr.sbin/bhyve/pci_uart.c
@@ -104,6 +104,8 @@
 	pci_set_cfgdata16(pi, PCIR_DEVICE, COM_DEV);
 	pci_set_cfgdata16(pi, PCIR_VENDOR, COM_VENDOR);
 	pci_set_cfgdata8(pi, PCIR_CLASS, PCIC_SIMPLECOMM);
+	pci_set_cfgdata8(pi, PCIR_SUBCLASS, PCIS_SIMPLECOMM_UART);
+	pci_set_cfgdata8(pi, PCIR_PROGIF, PCIP_SIMPLECOMM_UART_16550A);
 
 	sc = uart_ns16550_init(pci_uart_intr_assert, pci_uart_intr_deassert,
 	    pi);