Having the virtual IOMMU created with --iommu is one thing, but we also
need a way to decide if a virtio-blk device should be attached to this
virtual IOMMU or not. That's why we introduce an extra option "iommu"
with the value "on" or "off". By default, the device is not attached,
which means "iommu=off".
One side effect of this new option is that we had to introduce a new
option for the disk path, simply called "path=".
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
