The machine may need to pass reserved regions to the
virtio-iommu-pci device (such as the MSI window on x86
or the MSI doorbells on ARM).

So let's add an array of Interval properties.

Note: if some reserved regions are already set by the
machine code - which should be the case in general -,
the length of the property array is already set and
prevents the end-user from modifying them. For example,
attempting to use:

-device virtio-iommu-pci,\
 len-reserved-regions=1,reserved-regions[0]=0xfee00000:0xfeefffff:1

would result in the following error message:

qemu-system-aarch64: -device virtio-iommu-pci,addr=0xa,
len-reserved-regions=1,reserved-regions[0]=0xfee00000:0xfeefffff:1:
array size property len-reserved-regions may not be set more than once

Otherwise, for example, adding two reserved regions is achieved
using the following options:

-device virtio-iommu-pci,addr=0xa,len-reserved-regions=2,\
 reserved-regions[0]=0xfee00000:0xfeefffff:1,\
 reserved-regions[1]=0x1000000:100ffff:1

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Message-id: 20200629070404.10969-5-eric.auger@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>