Only first 4 disks can be emulated as IDE disks by QEMU. Specifically,
CDROM must be one of those first 4 disks, otherwise it will be
ignored. This is especially important if one wants to boot the VM from
that CDROM.
Since xvdd normally is a kernel-related volume (boot image, modules) it
makes perfect sense to re-use it for CDROM. It is either set for kernel
volume (in which case, VM should boot from it and not the CDROM), or
(possibly bootable) CDROM.
This needs to be done in two places:
- BlockExtension for dynamic attach
- libvirt xen.xml - for before-boot attach
In theory the latter would be enough, but it would be quite confusing
that device will get different options depending on when it's attached
(in addition to whether the kernel is set - introduced here).
This all also means, xvdd not always is a "system disk". Adjust listing
connected disks accordingly.
Add property for IPv6 address ('ip6'). Build default value similarly to
IPv4 - common prefix + QID or Disp ID (for DispVMs).
This all is disabled unless 'ipv6' feature is enabled. It is inherited
from netvm (not template).
Even when enabled, VM may decide to not use it - or simply not support
it.
QubesOS/qubes-issues#718
Instead of old per-VM flag 'pci_strictreset', now implement this as
per-device flag using features. To not fail on particular device
assignment set 'pci-no-strict-reset/DEVICE-BDF' to True. For
example 'pci-no-strict-reset/00:1b.0'.
QubesOS/qubes-issues#2257
