vfio/pci: Align MSIX Table and PBA size to guest maximum page size

When allocating MMIO space for the MSI-X table, kvmtool rounds the
allocation to the host's page size to make it as easy as possible for the
guest to map the table to a page, if it wants to (and doesn't do BAR
reassignment, like the x86 architecture for example). However, the host's
page size can differ from the guest's on architectures which support
multiple page sizes. For example, arm64 supports three different page size,
and it is possible for the host to be using 4k pages, while the guest is
using 64k pages.

To make sure the allocation is always aligned to a guest's page size, round
it up to the maximum architectural page size. Do the same for the pending
bit array if it lives in its own BAR.

Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Link: https://lore.kernel.org/r/20211012132510.42134-8-alexandru.elisei@arm.com


Signed-off-by: Will Deacon <will@kernel.org>