vfio/ap: Validate iova during dma_unmap and trigger irq disable

vfio/ap: Validate iova during dma_unmap and trigger irq disable

Currently, each mapped iova is stashed in its associated vfio_ap_queue;
when we get an unmap request, validate that it matches with one or more of
these stashed values before attempting unpins.

Each stashed iova represents IRQ that was enabled for a queue.  Therefore,
if a match is found, trigger IRQ disable for this queue to ensure that
underlying firmware will no longer try to use the associated pfn after the
page is unpinned. IRQ disable will also handle the associated unpin.

Link: https://lore.kernel.org/r/20221202135402.756470-3-yi.l.liu@intel.com
Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>