This patch was originally submitted via 
https://gitlab.com/libvirt/libvirt/-/merge_requests/19

That merge request contains additional information, if you find the
commit message of the patch lacking in some way. It did pass CI and
the test suite four weeks ago, seems small enough, and the rebase
had no conflicts, so I didn't run the tests again on current master.

And based on the comment from Peter Krempa in that merge request,
it probably needs further discussion with QEMU developers.

FWIW: while the installer generally works, I'm experiencing massive
timeouts from the "Out of Box Experience" (OOBE) part of the
Windows configuration after the install. And the latest ISOs don't
even start in QEMU (5.1 and older) for me on Debian, so I used 1909
instead of the 2004 ISO "releases". I'm running the aarch64 system
QEMU on x86_64 Debian Buster with my current QEMU build.

Jan-Marek Glogowski (1):
  QEMU: support USB cdrom devices

 src/qemu/qemu_command.c                       | 21 ++++++++++++++++++-
 src/qemu/qemu_command.h                       |  1 +
 src/qemu/qemu_domain.c                        |  2 +-
 .../disk-cdrom-bus-other.x86_64-latest.args   | 12 +++++------
 4 files changed, 28 insertions(+), 8 deletions(-)

-- 
2.20.1