1 files changed, 95 insertions, 20 deletions

diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index 80930ce04a16..1f793219cac6 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c
@@ -71,6 +71,7 @@ struct viommu_domain {
 	struct rb_root_cached		mappings;
 
 	unsigned long			nr_endpoints;
+	bool				bypass;
 };
 
 struct viommu_endpoint {
@@ -310,8 +311,8 @@ out_unlock:
  *
  * On success, return the new mapping. Otherwise return NULL.
  */
-static int viommu_add_mapping(struct viommu_domain *vdomain, unsigned long iova,
-			      phys_addr_t paddr, size_t size, u32 flags)
+static int viommu_add_mapping(struct viommu_domain *vdomain, u64 iova, u64 end,
+			      phys_addr_t paddr, u32 flags)
 {
 	unsigned long irqflags;
 	struct viommu_mapping *mapping;
@@ -322,7 +323,7 @@ static int viommu_add_mapping(struct viommu_domain *vdomain, unsigned long iova,
 
 	mapping->paddr		= paddr;
 	mapping->iova.start	= iova;
-	mapping->iova.last	= iova + size - 1;
+	mapping->iova.last	= end;
 	mapping->flags		= flags;
 
 	spin_lock_irqsave(&vdomain->mappings_lock, irqflags);
@@ -337,26 +338,24 @@ static int viommu_add_mapping(struct viommu_domain *vdomain, unsigned long iova,
  *
  * @vdomain: the domain
  * @iova: start of the range
- * @size: size of the range. A size of 0 corresponds to the entire address
- *	space.
+ * @end: end of the range
  *
- * On success, returns the number of unmapped bytes (>= size)
+ * On success, returns the number of unmapped bytes
  */
 static size_t viommu_del_mappings(struct viommu_domain *vdomain,
-				  unsigned long iova, size_t size)
+				  u64 iova, u64 end)
 {
 	size_t unmapped = 0;
 	unsigned long flags;
-	unsigned long last = iova + size - 1;
 	struct viommu_mapping *mapping = NULL;
 	struct interval_tree_node *node, *next;
 
 	spin_lock_irqsave(&vdomain->mappings_lock, flags);
-	next = interval_tree_iter_first(&vdomain->mappings, iova, last);
+	next = interval_tree_iter_first(&vdomain->mappings, iova, end);
 	while (next) {
 		node = next;
 		mapping = container_of(node, struct viommu_mapping, iova);
-		next = interval_tree_iter_next(node, iova, last);
+		next = interval_tree_iter_next(node, iova, end);
 
 		/* Trying to split a mapping? */
 		if (mapping->iova.start < iova)
@@ -377,6 +376,55 @@ static size_t viommu_del_mappings(struct viommu_domain *vdomain,
 }
 
 /*
+ * Fill the domain with identity mappings, skipping the device's reserved
+ * regions.
+ */
+static int viommu_domain_map_identity(struct viommu_endpoint *vdev,
+				      struct viommu_domain *vdomain)
+{
+	int ret;
+	struct iommu_resv_region *resv;
+	u64 iova = vdomain->domain.geometry.aperture_start;
+	u64 limit = vdomain->domain.geometry.aperture_end;
+	u32 flags = VIRTIO_IOMMU_MAP_F_READ | VIRTIO_IOMMU_MAP_F_WRITE;
+	unsigned long granule = 1UL << __ffs(vdomain->domain.pgsize_bitmap);
+
+	iova = ALIGN(iova, granule);
+	limit = ALIGN_DOWN(limit + 1, granule) - 1;
+
+	list_for_each_entry(resv, &vdev->resv_regions, list) {
+		u64 resv_start = ALIGN_DOWN(resv->start, granule);
+		u64 resv_end = ALIGN(resv->start + resv->length, granule) - 1;
+
+		if (resv_end < iova || resv_start > limit)
+			/* No overlap */
+			continue;
+
+		if (resv_start > iova) {
+			ret = viommu_add_mapping(vdomain, iova, resv_start - 1,
+						 (phys_addr_t)iova, flags);
+			if (ret)
+				goto err_unmap;
+		}
+
+		if (resv_end >= limit)
+			return 0;
+
+		iova = resv_end + 1;
+	}
+
+	ret = viommu_add_mapping(vdomain, iova, limit, (phys_addr_t)iova,
+				 flags);
+	if (ret)
+		goto err_unmap;
+	return 0;
+
+err_unmap:
+	viommu_del_mappings(vdomain, 0, iova);
+	return ret;
+}
+
+/*
  * viommu_replay_mappings - re-send MAP requests
  *
  * When reattaching a domain that was previously detached from all endpoints,
@@ -422,7 +470,7 @@ static int viommu_add_resv_mem(struct viommu_endpoint *vdev,
 	size_t size;
 	u64 start64, end64;
 	phys_addr_t start, end;
-	struct iommu_resv_region *region = NULL;
+	struct iommu_resv_region *region = NULL, *next;
 	unsigned long prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
 
 	start = start64 = le64_to_cpu(mem->start);
@@ -453,7 +501,12 @@ static int viommu_add_resv_mem(struct viommu_endpoint *vdev,
 	if (!region)
 		return -ENOMEM;
 
-	list_add(&region->list, &vdev->resv_regions);
+	/* Keep the list sorted */
+	list_for_each_entry(next, &vdev->resv_regions, list) {
+		if (next->start > region->start)
+			break;
+	}
+	list_add_tail(&region->list, &next->list);
 	return 0;
 }
 
@@ -587,7 +640,9 @@ static struct iommu_domain *viommu_domain_alloc(unsigned type)
 {
 	struct viommu_domain *vdomain;
 
-	if (type != IOMMU_DOMAIN_UNMANAGED && type != IOMMU_DOMAIN_DMA)
+	if (type != IOMMU_DOMAIN_UNMANAGED &&
+	    type != IOMMU_DOMAIN_DMA &&
+	    type != IOMMU_DOMAIN_IDENTITY)
 		return NULL;
 
 	vdomain = kzalloc(sizeof(*vdomain), GFP_KERNEL);
@@ -630,6 +685,21 @@ static int viommu_domain_finalise(struct viommu_endpoint *vdev,
 	vdomain->map_flags	= viommu->map_flags;
 	vdomain->viommu		= viommu;
 
+	if (domain->type == IOMMU_DOMAIN_IDENTITY) {
+		if (virtio_has_feature(viommu->vdev,
+				       VIRTIO_IOMMU_F_BYPASS_CONFIG)) {
+			vdomain->bypass = true;
+			return 0;
+		}
+
+		ret = viommu_domain_map_identity(vdev, vdomain);
+		if (ret) {
+			ida_free(&viommu->domain_ids, vdomain->id);
+			vdomain->viommu = NULL;
+			return -EOPNOTSUPP;
+		}
+	}
+
 	return 0;
 }
 
@@ -637,8 +707,8 @@ static void viommu_domain_free(struct iommu_domain *domain)
 {
 	struct viommu_domain *vdomain = to_viommu_domain(domain);
 
-	/* Free all remaining mappings (size 2^64) */
-	viommu_del_mappings(vdomain, 0, 0);
+	/* Free all remaining mappings */
+	viommu_del_mappings(vdomain, 0, ULLONG_MAX);
 
 	if (vdomain->viommu)
 		ida_free(&vdomain->viommu->domain_ids, vdomain->id);
@@ -673,7 +743,7 @@ static int viommu_attach_dev(struct iommu_domain *domain, struct device *dev)
 
 	/*
 	 * In the virtio-iommu device, when attaching the endpoint to a new
-	 * domain, it is detached from the old one and, if as as a result the
+	 * domain, it is detached from the old one and, if as a result the
 	 * old domain isn't attached to any endpoint, all mappings are removed
 	 * from the old domain and it is freed.
 	 *
@@ -691,6 +761,9 @@ static int viommu_attach_dev(struct iommu_domain *domain, struct device *dev)
 		.domain		= cpu_to_le32(vdomain->id),
 	};
 
+	if (vdomain->bypass)
+		req.flags |= cpu_to_le32(VIRTIO_IOMMU_ATTACH_F_BYPASS);
+
 	for (i = 0; i < fwspec->num_ids; i++) {
 		req.endpoint = cpu_to_le32(fwspec->ids[i]);
 
@@ -720,6 +793,7 @@ static int viommu_map(struct iommu_domain *domain, unsigned long iova,
 {
 	int ret;
 	u32 flags;
+	u64 end = iova + size - 1;
 	struct virtio_iommu_req_map map;
 	struct viommu_domain *vdomain = to_viommu_domain(domain);
 
@@ -730,7 +804,7 @@ static int viommu_map(struct iommu_domain *domain, unsigned long iova,
 	if (flags & ~vdomain->map_flags)
 		return -EINVAL;
 
-	ret = viommu_add_mapping(vdomain, iova, paddr, size, flags);
+	ret = viommu_add_mapping(vdomain, iova, end, paddr, flags);
 	if (ret)
 		return ret;
 
@@ -739,7 +813,7 @@ static int viommu_map(struct iommu_domain *domain, unsigned long iova,
 		.domain		= cpu_to_le32(vdomain->id),
 		.virt_start	= cpu_to_le64(iova),
 		.phys_start	= cpu_to_le64(paddr),
-		.virt_end	= cpu_to_le64(iova + size - 1),
+		.virt_end	= cpu_to_le64(end),
 		.flags		= cpu_to_le32(flags),
 	};
 
@@ -748,7 +822,7 @@ static int viommu_map(struct iommu_domain *domain, unsigned long iova,
 
 	ret = viommu_send_req_sync(vdomain->viommu, &map, sizeof(map));
 	if (ret)
-		viommu_del_mappings(vdomain, iova, size);
+		viommu_del_mappings(vdomain, iova, end);
 
 	return ret;
 }
@@ -761,7 +835,7 @@ static size_t viommu_unmap(struct iommu_domain *domain, unsigned long iova,
 	struct virtio_iommu_req_unmap unmap;
 	struct viommu_domain *vdomain = to_viommu_domain(domain);
 
-	unmapped = viommu_del_mappings(vdomain, iova, size);
+	unmapped = viommu_del_mappings(vdomain, iova, iova + size - 1);
 	if (unmapped < size)
 		return 0;
 
@@ -1132,6 +1206,7 @@ static unsigned int features[] = {
 	VIRTIO_IOMMU_F_DOMAIN_RANGE,
 	VIRTIO_IOMMU_F_PROBE,
 	VIRTIO_IOMMU_F_MMIO,
+	VIRTIO_IOMMU_F_BYPASS_CONFIG,
 };
 
 static struct virtio_device_id id_table[] = {