1 files changed, 27 insertions, 10 deletions

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index d199d144460c..e385a99e25e1 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -960,14 +960,12 @@ static int iommu_create_device_direct_mappings(struct iommu_domain *domain,
 	unsigned long pg_size;
 	int ret = 0;
 
-	if (!iommu_is_dma_domain(domain))
-		return 0;
-
-	BUG_ON(!domain->pgsize_bitmap);
-
-	pg_size = 1UL << __ffs(domain->pgsize_bitmap);
+	pg_size = domain->pgsize_bitmap ? 1UL << __ffs(domain->pgsize_bitmap) : 0;
 	INIT_LIST_HEAD(&mappings);
 
+	if (WARN_ON_ONCE(iommu_is_dma_domain(domain) && !pg_size))
+		return -EINVAL;
+
 	iommu_get_resv_regions(dev, &mappings);
 
 	/* We need to consider overlapping regions for different devices */
@@ -975,13 +973,17 @@ static int iommu_create_device_direct_mappings(struct iommu_domain *domain,
 		dma_addr_t start, end, addr;
 		size_t map_size = 0;
 
-		start = ALIGN(entry->start, pg_size);
-		end   = ALIGN(entry->start + entry->length, pg_size);
+		if (entry->type == IOMMU_RESV_DIRECT)
+			dev->iommu->require_direct = 1;
 
-		if (entry->type != IOMMU_RESV_DIRECT &&
-		    entry->type != IOMMU_RESV_DIRECT_RELAXABLE)
+		if ((entry->type != IOMMU_RESV_DIRECT &&
+		     entry->type != IOMMU_RESV_DIRECT_RELAXABLE) ||
+		    !iommu_is_dma_domain(domain))
 			continue;
 
+		start = ALIGN(entry->start, pg_size);
+		end   = ALIGN(entry->start + entry->length, pg_size);
+
 		for (addr = start; addr <= end; addr += pg_size) {
 			phys_addr_t phys_addr;
 
@@ -2122,6 +2124,21 @@ static int __iommu_device_set_domain(struct iommu_group *group,
 {
 	int ret;
 
+	/*
+	 * If the device requires IOMMU_RESV_DIRECT then we cannot allow
+	 * the blocking domain to be attached as it does not contain the
+	 * required 1:1 mapping. This test effectively excludes the device
+	 * being used with iommu_group_claim_dma_owner() which will block
+	 * vfio and iommufd as well.
+	 */
+	if (dev->iommu->require_direct &&
+	    (new_domain->type == IOMMU_DOMAIN_BLOCKED ||
+	     new_domain == group->blocking_domain)) {
+		dev_warn(dev,
+			 "Firmware has requested this device have a 1:1 IOMMU mapping, rejecting configuring the device without a 1:1 mapping. Contact your platform vendor.\n");
+		return -EINVAL;
+	}
+
 	if (dev->iommu->attach_deferred) {
 		if (new_domain == group->default_domain)
 			return 0;