On further investigation, the "No such file or directory" error occurs when using snapshot=on.
ie: This fails: ./x86_64-softmmu/qemu-system-x86_64 -drive 'file=http://127.0.0.1/~rjones/cirros-0.3.1-x86_64-disk.img,if=virtio,snapshot=on' This works: ./x86_64-softmmu/qemu-system-x86_64 -drive 'file=http://127.0.0.1/~rjones/cirros-0.3.1-x86_64-disk.img,if=virtio,readonly=on' Also, creating a qcow2 file which has the http://... path as its backing file also works (which should have the same effect as snapshot=on, but I understand the implementation is a bit different). Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Fedora Windows cross-compiler. Compile Windows programs, test, and build Windows installers. Over 100 libraries supported. http://fedoraproject.org/wiki/MinGW