iommu/vt-d: Duplicate iommu_resv_region objects per device list

intel_iommu_get_resv_regions() aims to return the list of
reserved regions accessible by a given @device. However several
devices can access the same reserved memory region and when
building the list it is not safe to use a single iommu_resv_region
object, whose container is the RMRR. This iommu_resv_region must
be duplicated per device reserved region list.

Let's remove the struct iommu_resv_region from the RMRR unit
and allocate the iommu_resv_region directly in
intel_iommu_get_resv_regions(). We hold the dmar_global_lock instead
of the rcu-lock to allow sleeping.

Fixes: 0659b8dc ("iommu/vt-d: Implement reserved region get/put callbacks")
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/intel-iommu.c

@@ -324,7 +324,6 @@ struct dmar_rmrr_unit {
 	u64	end_address;		/* reserved end address */
 	struct dmar_dev_scope *devices;	/* target devices */
 	int	devices_cnt;		/* target device count */
-	struct iommu_resv_region *resv; /* reserved region handle */
 };
 
 struct dmar_atsr_unit {
@@ -4050,7 +4049,6 @@ static inline void init_iommu_pm_ops(void) {}
 int __init dmar_parse_one_rmrr(struct acpi_dmar_header *header, void *arg)
 {
 	struct acpi_dmar_reserved_memory *rmrr;
-	int prot = DMA_PTE_READ|DMA_PTE_WRITE;
 	struct dmar_rmrr_unit *rmrru;
 	size_t length;
 
@@ -4064,22 +4062,16 @@ int __init dmar_parse_one_rmrr(struct acpi_dmar_header *header, void *arg)
 	rmrru->end_address = rmrr->end_address;
 
 	length = rmrr->end_address - rmrr->base_address + 1;
-	rmrru->resv = iommu_alloc_resv_region(rmrr->base_address, length, prot,
-					      IOMMU_RESV_DIRECT);
-	if (!rmrru->resv)
-		goto free_rmrru;
 
 	rmrru->devices = dmar_alloc_dev_scope((void *)(rmrr + 1),
 				((void *)rmrr) + rmrr->header.length,
 				&rmrru->devices_cnt);
 	if (rmrru->devices_cnt && rmrru->devices == NULL)
-		goto free_all;
+		goto free_rmrru;
 
 	list_add(&rmrru->list, &dmar_rmrr_units);
 
 	return 0;
-free_all:
-	kfree(rmrru->resv);
 free_rmrru:
 	kfree(rmrru);
 out:
@@ -4297,7 +4289,6 @@ static void intel_iommu_free_dmars(void)
 	list_for_each_entry_safe(rmrru, rmrr_n, &dmar_rmrr_units, list) {
 		list_del(&rmrru->list);
 		dmar_free_dev_scope(&rmrru->devices, &rmrru->devices_cnt);
-		kfree(rmrru->resv);
 		kfree(rmrru);
 	}
 
@@ -5400,22 +5391,33 @@ static void intel_iommu_remove_device(struct device *dev)
 static void intel_iommu_get_resv_regions(struct device *device,
 					 struct list_head *head)
 {
+	int prot = DMA_PTE_READ | DMA_PTE_WRITE;
 	struct iommu_resv_region *reg;
 	struct dmar_rmrr_unit *rmrr;
 	struct device *i_dev;
 	int i;
 
-	rcu_read_lock();
+	down_read(&dmar_global_lock);
 	for_each_rmrr_units(rmrr) {
 		for_each_active_dev_scope(rmrr->devices, rmrr->devices_cnt,
 					  i, i_dev) {
+			struct iommu_resv_region *resv;
+			size_t length;
+
 			if (i_dev != device)
 				continue;
 
-			list_add_tail(&rmrr->resv->list, head);
+			length = rmrr->end_address - rmrr->base_address + 1;
+			resv = iommu_alloc_resv_region(rmrr->base_address,
+						       length, prot,
+						       IOMMU_RESV_DIRECT);
+			if (!resv)
+				break;
+
+			list_add_tail(&resv->list, head);
 		}
 	}
-	rcu_read_unlock();
+	up_read(&dmar_global_lock);
 
 #ifdef CONFIG_INTEL_IOMMU_FLOPPY_WA
 	if (dev_is_pci(device)) {
@@ -5443,10 +5445,8 @@ static void intel_iommu_put_resv_regions(struct device *dev,
 {
 	struct iommu_resv_region *entry, *next;
 
-	list_for_each_entry_safe(entry, next, head, list) {
-		if (entry->type == IOMMU_RESV_MSI)
-			kfree(entry);
-	}
+	list_for_each_entry_safe(entry, next, head, list)
+		kfree(entry);
 }
 
 int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct device *dev)