[Pkg-libvirt-maintainers] Bug#939370: libxl: Defining a virtual floppy succeeds, but affected domain doesn't start

[Olaf Martens]

Package: libvirt-daemon
Version: 5.0.0-4
Severity: normal

Dear maintainer,

when attempting to define a virtual floppy drive, just defining a domain
supposed to make use of that works fine, however, as soon as it is to be fired
up, libxl hiccups. This has been an issue since libvirt 3.0.0 (with Xen 4.8.0)
and persists with libvirt 5.0.0 (Xen 4.11.0).
By digging through the source code of libxl I noticed that the only special
cases that are checked besides the normal virtual harddisks are virtual CD-ROM
drives.
No such exception is present for FDDs so they hit the functions
libxl__device_from_disk and device_disk_add, both of which report an error
(invalid or unsupported virtual disk identifier). The type of backend (file,
volume, whatever) is irrelevant, the same behavior is experienced in every
case - in both function the error is reported right after the function
libxl__device_disk_dev_number has been invoked, which in turn prevents the VM
in question to start up.

This is particularly nasty if you have to rely on a working FDD to get
something installed.


Kind regards,

Olaf


-- System Information:
Debian Release: 10.0
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 5.2.0-0.bpo.2-amd64 (SMP w/8 CPU cores)
Kernel taint flags: TAINT_WARN
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8), LANGUAGE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: SELinux: enabled - Mode: Permissive - Policy name: default

Versions of packages libvirt-daemon depends on:
ii  libacl1             2.2.53-4
ii  libapparmor1        2.13.2-10
ii  libaudit1           1:2.8.4-3
ii  libavahi-client3    0.7-4+b1
ii  libavahi-common3    0.7-4+b1
ii  libblkid1           2.33.1-0.1
ii  libc6               2.28-10
ii  libcap-ng0          0.7.9-2
ii  libcurl3-gnutls     7.64.0-4
ii  libdbus-1-3         1.12.16-1
ii  libdevmapper1.02.1  2:1.02.155-3
ii  libfuse2            2.9.9-1
ii  libgcc1             1:8.3.0-6
ii  libgnutls30         3.6.7-4
ii  libnetcf1           1:0.2.8-1+b2
ii  libnl-3-200         3.4.0-1
ii  libnl-route-3-200   3.4.0-1
ii  libnuma1            2.0.12-1
ii  libparted2          3.2-25
ii  libpcap0.8          1.8.1-6
ii  libpciaccess0       0.14-1
ii  libsasl2-2          2.1.27+dfsg-1
ii  libselinux1         2.8-1+b1
ii  libssh2-1           1.8.0-2.1
ii  libudev1            241-5
ii  libvirt0            5.0.0-4
ii  libxenmisc4.11      4.11.1+92-g6c33308a8d-2
ii  libxenstore3.0      4.11.1+92-g6c33308a8d-2
ii  libxentoollog1      4.11.1+92-g6c33308a8d-2
ii  libxml2             2.9.4+dfsg1-7+b3
ii  libyajl2            2.1.0-3

Versions of packages libvirt-daemon recommends:
ii  libxml2-utils   2.9.4+dfsg1-7+b3
ii  netcat-openbsd  1.195-2
ii  qemu-kvm        1:3.1+dfsg-8+deb10u2

Versions of packages libvirt-daemon suggests:
pn  libvirt-daemon-driver-storage-gluster  <none>
pn  libvirt-daemon-driver-storage-rbd      <none>
pn  libvirt-daemon-driver-storage-zfs      <none>
ii  libvirt-daemon-system                  5.0.0-4
pn  numad                                  <none>

-- no debconf information