From: Alexander Graf <graf@amazon.com>
Apple has its own virtio-blk PCI device ID where it deviates from the
official virtio-pci spec slightly: It puts a new "apple type"
field at a static offset in config space and introduces a new barrier
command.
This patch first creates a mechanism for virtio-blk downstream classes to
handle unknown commands. It then creates such a downstream class and a new
vmapple-virtio-blk-pci class which support the additional apple type config
identifier as well as the barrier command.
It then exposes 2 subclasses from that that we can use to expose root and
aux virtio-blk devices: "vmapple-virtio-root" and "vmapple-virtio-aux".
Signed-off-by: Alexander Graf <graf@amazon.com>
Signed-off-by: Phil Dennis-Jordan <phil@philjordan.eu>