iommu/vt-d: Per PCI device pasid table interfaces

This patch adds the interfaces for per PCI device pasid
table management. Currently we allocate one pasid table
for all PCI devices under the scope of an IOMMU. It's
insecure in some cases where multiple devices under one
single IOMMU unit support PASID features. With per PCI
device pasid table, we can achieve finer protection and
isolation granularity.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Liu Yi L <yi.l.liu@intel.com>
Suggested-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/intel-iommu.c

@@ -2451,6 +2451,7 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu,
 	info->dev = dev;
 	info->domain = domain;
 	info->iommu = iommu;
+	info->pasid_table = NULL;
 
 	if (dev && dev_is_pci(dev)) {
 		struct pci_dev *pdev = to_pci_dev(info->dev);