intel-iommu: Fix reattaching of devices to identity mapping domain

When we reattach a device to the si_domain (because it's been removed
from a VM), we weren't calling domain_context_mapping() to actually tell
the hardware about that.

We should really put the call to domain_context_mapping() into
domain_add_dev_info() -- we never call the latter without also doing the
former, and we can keep the error paths simple that way. But that's a
cleanup which can wait for 2.6.32 now.
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

drivers/pci/intel-iommu.c

@@ -2475,6 +2475,9 @@ static int iommu_no_mapping(struct pci_dev *pdev)
 		if (pdev->dma_mask > DMA_BIT_MASK(32)) {
 			int ret;
 			ret = domain_add_dev_info(si_domain, pdev);
+			if (ret)
+				return 0;
+			ret = domain_context_mapping(si_domain, pdev, CONTEXT_TT_MULTI_LEVEL);
 			if (!ret) {
 				printk(KERN_INFO "64bit %s uses identity mapping\n",
 				       pci_name(pdev));