Hmm. By now I'm thinking aloud. According to the manpage (see below), "-blockdev" is the most "down to earth", true and modern way to specify the emulated disk - possibly needs to be combined with a "-device" to specify the guest-side emulated interface? Curiously, I cannot find a complete example...
The manpage says, that: -hda (etc) is the oldest form, nowadays a macro for -drive + -device (controller). -drive is a shorthand for "-blockdev + -device" So... where I'm using -drive, I might as well be using -blockdev . Plus something more? No clue... :-) Or perhaps use "-blockdev node-name=.." instead of "-drive id=.." ? The qemu docs chapter on "QEMU block drivers" gives this example: -blockdev driver=qcow2,file.filename=/path/to/image,file.locking=off,file.driver =file I.e., you should put your locking=off option into a -blockdev definition as you say. And, I have an idea: rather than refer to driver=qcow2 and file.filename, how about referring to the loopback device (NBD) that you already have, courtesy of qemu-nbd ? Would that perhaps circumvent the file lock? ;-) -blockdev node-name=xy,driver=raw,file.driver=host_device,\ file.filename=/dev/loop0,file.locking=off -device virtio-scsi-pci -device scsi-hd,drive=xy Further reading: https://manpages.debian.org/testing/qemu-system-x86/qemu-system-x86_64 .1.en.html#Block_device_options https://unix.stackexchange.com/questions/753092/what-is-the-difference -between-these-two-blockdev-declarations https://www.qemu.org/docs/master/system/qemu-block-drivers.html#disk-i mage-file-locking Frank
