UCT/API/IB: Add support for dmabuf registration

src/tools/info/tl_info.c

@@ -448,8 +448,12 @@ static void print_md_info(uct_component_h component,
                    size_limit_to_str(0, md_attr.max_alloc));
         }
         if (md_attr.flags & UCT_MD_FLAG_REG) {
-            printf("#             register: %s, cost: ",
+            printf("#             register: %s",
                    size_limit_to_str(0, md_attr.max_reg));
+            if (md_attr.flags & UCT_MD_FLAG_REG_DMABUF) {
+                printf(", dmabuf");
+            }
+            printf(", cost: ");
             PRINT_LINEAR_FUNC_NS(&md_attr.reg_cost);
         }
         if (md_attr.flags & UCT_MD_FLAG_NEED_RKEY) {

src/uct/api/uct.h

@@ -754,7 +754,12 @@ enum {
      * MD supports exporting memory keys with another process using the same
      * device or attaching to an exported memory key.
      */
-    UCT_MD_FLAG_EXPORTED_MKEY = UCS_BIT(9)
+    UCT_MD_FLAG_EXPORTED_MKEY = UCS_BIT(9),
+
+    /**
+     * MD supports registering a dmabuf file descriptor.
+     */
+    UCT_MD_FLAG_REG_DMABUF    = UCS_BIT(10)
 };
 
 /**

src/uct/api/uct_def.h

@@ -27,6 +27,7 @@
 #define UCT_MEM_HANDLE_NULL        NULL
 #define UCT_INVALID_RKEY           ((uintptr_t)(-1))
 #define UCT_INLINE_API             static UCS_F_ALWAYS_INLINE
+#define UCT_DMABUF_FD_INVALID      -1
 
 
 /**

src/uct/api/v2/uct_v2.h

@@ -195,7 +195,9 @@ typedef struct {
  * @brief MD memory registration operation flags.
  */
 typedef enum {
-    UCT_MD_MEM_REG_FIELD_FLAGS = UCS_BIT(0)
+    UCT_MD_MEM_REG_FIELD_FLAGS         = UCS_BIT(0),
+    UCT_MD_MEM_REG_FIELD_DMABUF_FD     = UCS_BIT(1),
+    UCT_MD_MEM_REG_FIELD_DMABUF_OFFSET = UCS_BIT(2)
 } uct_md_mem_reg_field_mask_t;
 
 
@@ -378,6 +380,45 @@ typedef struct uct_md_mem_reg_params {
      * Operation specific flags, using bits from @ref uct_md_mem_flags_t.
      */
     uint64_t                     flags;
+
+    /**
+     * dmabuf file descriptor of the memory region to register.
+     *
+     * If is set (along with its corresponding bit in the field_mask -
+     * @ref UCT_MD_MEM_REG_FIELD_DMABUF_FD), the memory region will be
+     * registered using dmabuf mechanism.
+     * Can be used only if the memory domain supports dmabuf registration by
+     * returning @ref UCT_MD_FLAG_REG_DMABUF flag from @ref uct_md_query_v2.
+     *
+     * When registering memory using dmabuf mechanism, any memory type is supported
+     * (assuming a valid dmabuf file descriptor could be created).
+     * Therefore, @ref uct_md_attr_v2_t.reg_mem_types field is not relevant for
+     * such registrations.
+     *
+     * If not set, it's assumed to be @ref UCT_DMABUF_FD_INVALID, and the memory
+     * region will be registered without using dmabuf mechanism.
+     *
+     * More information about dmabuf registration can be found in
+     * https://01.org/linuxgraphics/gfx-docs/drm/driver-api/dma-buf.html
+     */
+    int                          dmabuf_fd;
+
+    /**
+     * When @ref uct_md_mem_reg_params_t.dmabuf_fd is provided, this field
+     * specifies the offset of the region to register relative to the start of
+     * the underlying dmabuf region.
+     *
+     * If not set (along with its corresponding bit in the field_mask -
+     * @ref UCT_MD_MEM_REG_FIELD_DMABUF_OFFSET) it's assumed to be 0.
+     *
+     * @note The value of this field must be equal to the offset of the virtual
+     * address provided by the address parameter to @ref uct_md_mem_reg_v2 from
+     * the beginning of the memory region associated with
+     * @ref uct_md_mem_reg_params_t.dmabuf_fd.
+     * For example, if the virtual address is equal to the beginning of the
+     * dmabuf region, then this field must be omitted or set to 0.
+     */
+    size_t                       dmabuf_offset;
 } uct_md_mem_reg_params_t;