You can start 'none' without "-serial null". Examples: qemu-system-x86_64 -machine none qemu-system-x86_64 -machine none -monitor stdio qemu-system-x86_64 -machine none -nographic qemu-system-x86_64 -machine none -monitor stdio -display none
Your command line "qemu-system-x86_64 -machine none -nographic -monitor stdio" fails because "-nographic" says "please create a serial port using stdio" but "-monitor stdio" tries to use stdio for something else. You get the same message for any machine (eg "pc"), not just "none". If what you wanted was "just don't create the graphical display" that's "-display none" -- "-nographic" is a collection of things including both 'no display' and also 'default to creating a serial device to stdio' and 'default to creating a monitor muxed with that serial'. ** Changed in: qemu Status: New => Invalid -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1848231 Title: serial/parallel character devices created for the none-machine Status in QEMU: Invalid Bug description: The none-machine can not be started unless using "-serial null": qemu-system-x86_64 -machine none -nographic -monitor stdio QEMU 3.1.1 monitor - type 'help' for more information (qemu) qemu-system-x86_64: cannot use stdio by multiple character devices qemu-system-x86_64: could not connect serial device to character backend 'stdio' $ $ qemu-system-mips -machine none -nographic -serial null -monitor stdio QEMU 4.1.50 monitor - type 'help' for more information (qemu) info chardev parallel0: filename=null compat_monitor0: filename=stdio serial0: filename=null (qemu) To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1848231/+subscriptions