Re: [libvirt] [PATCH 2/2] qemu: use -incoming fd:n to avoid qemu holding fd indefinitely

https://bugzilla.redhat.com/show_bug.cgi?id=620363 When using -incoming stdio or -incoming exec:cat, qemu keeps the stdin fd open long after the migration is complete. Not to mention that exec:cat is horribly inefficient, by doubling the I/O and going through a popen interface in qemu. The new -incoming fd: of qemu 0.12.0 closes the fd after using it, and allows us to bypass an intermediary cat process for less I/O. It would also be possible to fix this bug for qemu< 0.12.0, by creating a dummy 'cat' process that reads from real fd and writes to a pipe, and pass the other end of the pipe into -incoming exec:cat or -incoming stdio, at the expense of even more I/O. I don't know if that is worth the patch, though.