Soft RoCE driver

Soft RoCE (RXE) - The software RoCE driver

ib_rxe implements the RDMA transport and registers to the RDMA core
device as a kernel verbs provider. It also implements the packet IO
layer. On the other hand ib_rxe registers to the Linux netdev stack
as a udp encapsulating protocol, in that case RDMA, for sending and
receiving packets over any Ethernet device.  This yields a RDMA
transport over the UDP/Ethernet network layer forming a RoCEv2
compatible device.

The configuration procedure of the Soft RoCE drivers requires
binding to any existing Ethernet network device. This is done with
/sys interface.

A userspace Soft RoCE library (librxe) provides user applications
the ability to run with Soft RoCE devices.  The use of rxe verbs ins
user space requires the inclusion of librxe as a device specifics
plug-in to libibverbs. librxe is packaged separately.

Architecture:

     +-----------------------------------------------------------+
     |                          Application                      |
     +-----------------------------------------------------------+
                            +-----------------------------------+
                            |             libibverbs            |
User                        +-----------------------------------+
                            +----------------+ +----------------+
                            | librxe         | | HW RoCE lib    |
                            +----------------+ +----------------+
+---------------------------------------------------------------+
     +--------------+                           +------------+
     | Sockets      |                           | RDMA ULP   |
     +--------------+                           +------------+
     +--------------+                  +---------------------+
     | TCP/IP       |                  | ib_core             |
     +--------------+                  +---------------------+
                             +------------+ +----------------+
Kernel                       | ib_rxe     | | HW RoCE driver |
                             +------------+ +----------------+
     +------------------------------------+
     | NIC driver                         |
     +------------------------------------+

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     +-----------------------------------------------------------+
     |                          Application                      |
     +-----------------------------------------------------------+
                            +-----------------------------------+
                            |             libibverbs            |
User                        +-----------------------------------+
                            +----------------+ +----------------+
                            | librxe         | | HW RoCE lib    |
                            +----------------+ +----------------+
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     +--------------+                           +------------+
     | Sockets      |                           | RDMA ULP   |
     +--------------+                           +------------+
     +--------------+                  +---------------------+
     | TCP/IP       |                  | ib_core             |
     +--------------+                  +---------------------+
                             +------------+ +----------------+
Kernel                       | ib_rxe     | | HW RoCE driver |
                             +------------+ +----------------+
     +------------------------------------+
     | NIC driver                         |
     +------------------------------------+
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Soft RoCE resources:

[1[ https://github.com/SoftRoCE/librxe-dev librxe - source code in
Github
[2] https://github.com/SoftRoCE/rxe-dev/wiki/rxe-dev:-Home - Soft RoCE
Wiki page
[3] https://github.com/SoftRoCE/librxe-dev - Soft RoCE userspace library

Signed-off-by: Kamal Heib <kamalh@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: Moni Shoua <monis@mellanox.com>
Reviewed-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 178 insertions, 0 deletions

diff --git a/drivers/infiniband/sw/rxe/rxe_queue.h b/drivers/infiniband/sw/rxe/rxe_queue.h
new file mode 100644
index 000000000000..239fd609c31e
--- /dev/null
+++ b/drivers/infiniband/sw/rxe/rxe_queue.h
@@ -0,0 +1,178 @@
+/*
+ * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
+ * Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *	- Redistributions of source code must retain the above
+ *	  copyright notice, this list of conditions and the following
+ *	  disclaimer.
+ *
+ *	- Redistributions in binary form must reproduce the above
+ *	  copyright notice, this list of conditions and the following
+ *	  disclaimer in the documentation and/or other materials
+ *	  provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef RXE_QUEUE_H
+#define RXE_QUEUE_H
+
+/* implements a simple circular buffer that can optionally be
+ * shared between user space and the kernel and can be resized
+
+ * the requested element size is rounded up to a power of 2
+ * and the number of elements in the buffer is also rounded
+ * up to a power of 2. Since the queue is empty when the
+ * producer and consumer indices match the maximum capacity
+ * of the queue is one less than the number of element slots
+ */
+
+/* this data structure is shared between user space and kernel
+ * space for those cases where the queue is shared. It contains
+ * the producer and consumer indices. Is also contains a copy
+ * of the queue size parameters for user space to use but the
+ * kernel must use the parameters in the rxe_queue struct
+ * this MUST MATCH the corresponding librxe struct
+ * for performance reasons arrange to have producer and consumer
+ * pointers in separate cache lines
+ * the kernel should always mask the indices to avoid accessing
+ * memory outside of the data area
+ */
+struct rxe_queue_buf {
+	__u32			log2_elem_size;
+	__u32			index_mask;
+	__u32			pad_1[30];
+	__u32			producer_index;
+	__u32			pad_2[31];
+	__u32			consumer_index;
+	__u32			pad_3[31];
+	__u8			data[0];
+};
+
+struct rxe_queue {
+	struct rxe_dev		*rxe;
+	struct rxe_queue_buf	*buf;
+	struct rxe_mmap_info	*ip;
+	size_t			buf_size;
+	size_t			elem_size;
+	unsigned int		log2_elem_size;
+	unsigned int		index_mask;
+};
+
+int do_mmap_info(struct rxe_dev *rxe,
+		 struct ib_udata *udata,
+		 bool is_req,
+		 struct ib_ucontext *context,
+		 struct rxe_queue_buf *buf,
+		 size_t buf_size,
+		 struct rxe_mmap_info **ip_p);
+
+struct rxe_queue *rxe_queue_init(struct rxe_dev *rxe,
+				 int *num_elem,
+				 unsigned int elem_size);
+
+int rxe_queue_resize(struct rxe_queue *q,
+		     unsigned int *num_elem_p,
+		     unsigned int elem_size,
+		     struct ib_ucontext *context,
+		     struct ib_udata *udata,
+		     /* Protect producers while resizing queue */
+		     spinlock_t *producer_lock,
+		     /* Protect consumers while resizing queue */
+		     spinlock_t *consumer_lock);
+
+void rxe_queue_cleanup(struct rxe_queue *queue);
+
+static inline int next_index(struct rxe_queue *q, int index)
+{
+	return (index + 1) & q->buf->index_mask;
+}
+
+static inline int queue_empty(struct rxe_queue *q)
+{
+	return ((q->buf->producer_index - q->buf->consumer_index)
+			& q->index_mask) == 0;
+}
+
+static inline int queue_full(struct rxe_queue *q)
+{
+	return ((q->buf->producer_index + 1 - q->buf->consumer_index)
+			& q->index_mask) == 0;
+}
+
+static inline void advance_producer(struct rxe_queue *q)
+{
+	q->buf->producer_index = (q->buf->producer_index + 1)
+			& q->index_mask;
+}
+
+static inline void advance_consumer(struct rxe_queue *q)
+{
+	q->buf->consumer_index = (q->buf->consumer_index + 1)
+			& q->index_mask;
+}
+
+static inline void *producer_addr(struct rxe_queue *q)
+{
+	return q->buf->data + ((q->buf->producer_index & q->index_mask)
+				<< q->log2_elem_size);
+}
+
+static inline void *consumer_addr(struct rxe_queue *q)
+{
+	return q->buf->data + ((q->buf->consumer_index & q->index_mask)
+				<< q->log2_elem_size);
+}
+
+static inline unsigned int producer_index(struct rxe_queue *q)
+{
+	return q->buf->producer_index;
+}
+
+static inline unsigned int consumer_index(struct rxe_queue *q)
+{
+	return q->buf->consumer_index;
+}
+
+static inline void *addr_from_index(struct rxe_queue *q, unsigned int index)
+{
+	return q->buf->data + ((index & q->index_mask)
+				<< q->buf->log2_elem_size);
+}
+
+static inline unsigned int index_from_addr(const struct rxe_queue *q,
+					   const void *addr)
+{
+	return (((u8 *)addr - q->buf->data) >> q->log2_elem_size)
+		& q->index_mask;
+}
+
+static inline unsigned int queue_count(const struct rxe_queue *q)
+{
+	return (q->buf->producer_index - q->buf->consumer_index)
+		& q->index_mask;
+}
+
+static inline void *queue_head(struct rxe_queue *q)
+{
+	return queue_empty(q) ? NULL : consumer_addr(q);
+}
+
+#endif /* RXE_QUEUE_H */