[PATCH v9 05/12] vfio: Introduce common function to add capabilities

[Kirti Wankhede <kwankhede@nvidia.com>]

Vendor driver using mediated device framework should use
vfio_info_add_capability() to add capabilities.
Introduced this function to reduce code duplication in vendor drivers.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
Change-Id: I6fca329fa2291f37a2c859d0bc97574d9e2ce1a6
---
 drivers/vfio/vfio.c  | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/vfio.h |  4 +++
 2 files changed, 82 insertions(+)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index a5a210005b65..e96cb3f7a23c 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1799,6 +1799,84 @@ void vfio_info_cap_shift(struct vfio_info_cap *caps, size_t offset)
 }
 EXPORT_SYMBOL_GPL(vfio_info_cap_shift);
 
+static int sparse_mmap_cap(struct vfio_info_cap *caps, void *cap_type)
+{
+	struct vfio_info_cap_header *header;
+	struct vfio_region_info_cap_sparse_mmap *sparse_cap, *sparse = cap_type;
+	size_t size;
+
+	size = sizeof(*sparse) + sparse->nr_areas *  sizeof(*sparse->areas);
+	header = vfio_info_cap_add(caps, size,
+				   VFIO_REGION_INFO_CAP_SPARSE_MMAP, 1);
+	if (IS_ERR(header))
+		return PTR_ERR(header);
+
+	sparse_cap = container_of(header,
+			struct vfio_region_info_cap_sparse_mmap, header);
+	sparse_cap->nr_areas = sparse->nr_areas;
+	memcpy(sparse_cap->areas, sparse->areas,
+	       sparse->nr_areas * sizeof(*sparse->areas));
+	return 0;
+}
+
+static int region_type_cap(struct vfio_info_cap *caps, void *cap_type)
+{
+	struct vfio_info_cap_header *header;
+	struct vfio_region_info_cap_type *type_cap, *cap = cap_type;
+
+	header = vfio_info_cap_add(caps, sizeof(*cap),
+				   VFIO_REGION_INFO_CAP_TYPE, 1);
+	if (IS_ERR(header))
+		return PTR_ERR(header);
+
+	type_cap = container_of(header, struct vfio_region_info_cap_type,
+				header);
+	type_cap->type = cap->type;
+	type_cap->subtype = cap->subtype;
+	return 0;
+}
+
+int vfio_info_add_capability(struct vfio_region_info *info,
+			     struct vfio_info_cap *caps,
+			     int cap_type_id,
+			     void *cap_type)
+{
+	int ret;
+
+	if (!cap_type)
+		return 0;
+
+	switch (cap_type_id) {
+	case VFIO_REGION_INFO_CAP_SPARSE_MMAP:
+		ret = sparse_mmap_cap(caps, cap_type);
+		if (ret)
+			return ret;
+		break;
+
+	case VFIO_REGION_INFO_CAP_TYPE:
+		ret = region_type_cap(caps, cap_type);
+		if (ret)
+			return ret;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	info->flags |= VFIO_REGION_INFO_FLAG_CAPS;
+
+	if (caps->size) {
+		if (info->argsz < sizeof(*info) + caps->size) {
+			info->argsz = sizeof(*info) + caps->size;
+			info->cap_offset = 0;
+		} else {
+			vfio_info_cap_shift(caps, sizeof(*info));
+			info->cap_offset = sizeof(*info);
+		}
+	}
+	return 0;
+}
+EXPORT_SYMBOL(vfio_info_add_capability);
+
 
 /*
  * Pin a set of guest PFNs and return their associated host PFNs for local
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 0bd25ba6223d..854a4b40be02 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -108,6 +108,10 @@ extern struct vfio_info_cap_header *vfio_info_cap_add(
 		struct vfio_info_cap *caps, size_t size, u16 id, u16 version);
 extern void vfio_info_cap_shift(struct vfio_info_cap *caps, size_t offset);
 
+extern int vfio_info_add_capability(struct vfio_region_info *info,
+				    struct vfio_info_cap *caps,
+				    int cap_type_id, void *cap_type);
+
 struct pci_dev;
 #ifdef CONFIG_EEH
 extern void vfio_spapr_pci_eeh_open(struct pci_dev *pdev);
-- 
2.7.0