iommu/vt-d: Allow devices with RMRRs to use identity domain

commit 9235cb1 upstream.

Since commit ea2447f ("intel-iommu: Prevent devices with
RMRRs from being placed into SI Domain"), the Intel IOMMU driver
doesn't allow any devices with RMRR locked to use the identity
domain. This was added to to fix the issue where the RMRR info
for devices being placed in and out of the identity domain gets
lost. This identity maps all RMRRs when setting up the identity
domain, so that devices with RMRRs could also use it.

Signed-off-by: Lu Baolu <[email protected]>
Signed-off-by: Joerg Roedel <[email protected]>
Cc: Alan Stern <[email protected]>
Cc: John Donnelly <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: LuBaolu

drivers/iommu/intel-iommu.c

@@ -2762,20 +2762,15 @@ static int __init si_domain_init(int hw)
 	}
 
 	/*
-	 * Normally we use DMA domains for devices which have RMRRs. But we
-	 * loose this requirement for graphic and usb devices. Identity map
-	 * the RMRRs for graphic and USB devices so that they could use the
-	 * si_domain.
+	 * Identity map the RMRRs so that devices with RMRRs could also use
+	 * the si_domain.
 	 */
 	for_each_rmrr_units(rmrr) {
 		for_each_active_dev_scope(rmrr->devices, rmrr->devices_cnt,
 					  i, dev) {
 			unsigned long long start = rmrr->base_address;
 			unsigned long long end = rmrr->end_address;
 
-			if (device_is_rmrr_locked(dev))
-				continue;
-
 			if (WARN_ON(end < start ||
 				    end >> agaw_to_width(si_domain->agaw)))
 				continue;
@@ -2914,9 +2909,6 @@ static int device_def_domain_type(struct device *dev)
 	if (dev_is_pci(dev)) {
 		struct pci_dev *pdev = to_pci_dev(dev);
 
-		if (device_is_rmrr_locked(dev))
-			return IOMMU_DOMAIN_DMA;
-
 		/*
 		 * Prevent any device marked as untrusted from getting
 		 * placed into the statically identity mapping domain.
@@ -2954,9 +2946,6 @@ static int device_def_domain_type(struct device *dev)
 				return IOMMU_DOMAIN_DMA;
 		} else if (pci_pcie_type(pdev) == PCI_EXP_TYPE_PCI_BRIDGE)
 			return IOMMU_DOMAIN_DMA;
-	} else {
-		if (device_has_rmrr(dev))
-			return IOMMU_DOMAIN_DMA;
 	}
 
 	return (iommu_identity_mapping & IDENTMAP_ALL) ?