Bug 229712

Summary:	no cts/rts for serial port in bhyve connected to serial port on host
Product:	Base System	Reporter:	Stefan Bethke <stb>
Component:	misc	Assignee:	freebsd-virtualization (Nobody) <virtualization>
Status:	New ---
Severity:	Affects Only Me
Priority:	---
Version:	11.2-RELEASE
Hardware:	amd64
OS:	Any

Description Stefan Bethke 2018-07-12 07:13:42 UTC

When trying to run ppp(8) inside a VM against a USB serial port on the host, it appears that CTS/RTS is not handled correctly. While cu(1) can talk to the modem without issue, ppp(8) just hangs. Setting ctsrts to false in ppp(8) works around this. On the host, ppp(8) works fine without disabling ctsrts.

The bhyve VM is managed with vm-bhyve, and the USB serial port is exposed to the VM by -lcom2,/dev/cuaU0. The USB serial port is:
umodem0 on uhub1
umodem0: <HUAWEI Technology HUAWEI Mobile, class 0/0, rev 2.00/1.02, addr 1> on 
umodem0: data interface 0, has no CM over data, has no break

This is on 11.2-RELEASE with GENERIC.

Here's some more detail about the setup: https://lists.freebsd.org/pipermail/freebsd-stable/2018-July/089293.html

Right now I don't have a test case better than trying to set up this exact scenario.