Failed to map usbserial

[aleblack]

Describe the issue
Qemu failed to map /dev/tty.usbserial-X inside guest VM

Configuration

• UTM Version: 4.4.5 (94)
• macOS Version: 14.3
• Mac Chip (Intel, M1, ...): M2

I'm trying to map a usb serial port to the VM by adding these lines in the Arguments configuration of utm:
-chardev serial,path=/dev/tty.usbserial-D201046T,id=digifly -usb -device usb-serial,chardev,digifly

but I got an error from Qemu on startup:

QEMU error: QEMU exited from an error: qemu-aarch64-softmmu: -chardev serial,path=/dev/tty.usbserial-D201046T,id=digifly: Could not open '/dev/tty.usbserial-D201046T': Operation not permitted

but /dev/tty.usbserial-D201046T exist, it's owned by root and has permission of 666:
❯ ls -la /dev/tty.usbserial-D201046T
crw-rw-rw- 1 root wheel 0x9000002 Feb 8 15:48 /dev/tty.usbserial-D201046T

What am I doing wrong?

[DUOLabs333]

It might be because the user can't access it, and therefore, QEMU needs to run at root. This is hacky, but you could probably fix this by making the QEMU binary in UTM setuid so it automatically runs as root. A better idea may be chmod 777 <the path>. Can you open it as a user with cat?

[osy]

This is not possible as UTM is a sandboxed app. You might be able to do something like create a PTTY device and manually socat that into your USB device. Alternatively, capture the USB device directly in the VM.