[dpdk-dev] [PATCH v5 5/8] virtio-user: add device emulation layer APIs

[Jianfeng Tan]

Two device emulation layer APIs are added for virtio driver to call:
  - virtio_user_start_device()
  - virtio_user_stop_device()

These APIs will get called by virtio driver, and they call vhost adapter
layer APIs to implement the functionality. Besides, this patch defines
a struct named virtio_user_dev to help manage the data stands for this
kind of virtual device.

  ----------------------
  | ------------------ |
  | | virtio driver  | |
  | ------------------ |
  |         |          |
  | ------------------ | ------>  virtio-user PMD
  | | device emulate |-|----> (virtio_user_dev.c, virtio_user_dev.h)
  | |                | |
  | | vhost adapter  | |
  | ------------------ |
  ----------------------
            |
            |
            |
   ------------------
   | vhost backend  |
   ------------------

Signed-off-by: Huawei Xie <huawei.xie at intel.com>
Signed-off-by: Jianfeng Tan <jianfeng.tan at intel.com>
Acked-by: Neil Horman <nhorman at tuxdriver.com>
---
 drivers/net/virtio/Makefile                      |   1 +
 drivers/net/virtio/virtio_user/virtio_user_dev.c | 168 +++++++++++++++++++++++
 drivers/net/virtio/virtio_user/virtio_user_dev.h |  60 ++++++++
 3 files changed, 229 insertions(+)
 create mode 100644 drivers/net/virtio/virtio_user/virtio_user_dev.c
 create mode 100644 drivers/net/virtio/virtio_user/virtio_user_dev.h

diff --git a/drivers/net/virtio/Makefile b/drivers/net/virtio/Makefile
index c9f2bc0..68068bd 100644
--- a/drivers/net/virtio/Makefile
+++ b/drivers/net/virtio/Makefile
@@ -59,6 +59,7 @@ ifeq ($(CONFIG_RTE_VIRTIO_VDEV),y)
 SRCS-$(CONFIG_RTE_LIBRTE_VIRTIO_PMD) += virtio_user/vhost.c
 SRCS-$(CONFIG_RTE_LIBRTE_VIRTIO_PMD) += virtio_user/vhost_user.c
 SRCS-$(CONFIG_RTE_LIBRTE_VIRTIO_PMD) += virtio_user/vhost_kernel.c
+SRCS-$(CONFIG_RTE_LIBRTE_VIRTIO_PMD) += virtio_user/virtio_user_dev.c
 endif
 
 # this lib depends upon:
diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
new file mode 100644
index 0000000..41d8ad1
--- /dev/null
+++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
@@ -0,0 +1,168 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2010-2016 Intel Corporation. All rights reserved.
+ *   All rights reserved.
+ *
+ *   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.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <sys/eventfd.h>
+
+#include <rte_malloc.h>
+#include <rte_kvargs.h>
+
+#include "vhost.h"
+#include "virtio_user_dev.h"
+#include "../virtio_ethdev.h"
+
+static int
+virtio_user_kick_queue(struct virtio_user_dev *dev, uint32_t queue_sel)
+{
+	int callfd, kickfd;
+	struct vhost_vring_file file;
+	struct vhost_vring_state state;
+	struct vring *vring = &dev->vrings[queue_sel];
+	struct vhost_vring_addr addr = {
+		.index = queue_sel,
+		.desc_user_addr = (uint64_t)(uintptr_t)vring->desc,
+		.avail_user_addr = (uint64_t)(uintptr_t)vring->avail,
+		.used_user_addr = (uint64_t)(uintptr_t)vring->used,
+		.log_guest_addr = 0,
+		.flags = 0, /* disable log */
+	};
+
+	/* May use invalid flag, but some backend leverages kickfd and callfd as
+	 * criteria to judge if dev is alive. so finally we use real event_fd.
+	 */
+	callfd = eventfd(0, O_CLOEXEC | O_NONBLOCK);
+	if (callfd < 0) {
+		PMD_DRV_LOG(ERR, "callfd error, %s\n", strerror(errno));
+		return -1;
+	}
+	kickfd = eventfd(0, O_CLOEXEC | O_NONBLOCK);
+	if (kickfd < 0) {
+		close(callfd);
+		PMD_DRV_LOG(ERR, "kickfd error, %s\n", strerror(errno));
+		return -1;
+	}
+
+	/* Of all per virtqueue MSGs, make sure VHOST_SET_VRING_CALL come
+	 * firstly because vhost depends on this msg to allocate virtqueue
+	 * pair.
+	 */
+	file.index = queue_sel;
+	file.fd = callfd;
+	vhost_call(dev->vhostfd, dev->type, VHOST_MSG_SET_VRING_CALL, &file);
+	dev->callfds[queue_sel] = callfd;
+
+	state.index = queue_sel;
+	state.num = vring->num;
+	vhost_call(dev->vhostfd, dev->type, VHOST_MSG_SET_VRING_NUM, &state);
+
+	state.num = 0; /* no reservation */
+	vhost_call(dev->vhostfd, dev->type, VHOST_MSG_SET_VRING_BASE, &state);
+
+	vhost_call(dev->vhostfd, dev->type, VHOST_MSG_SET_VRING_ADDR, &addr);
+
+	/* Of all per virtqueue MSGs, make sure VHOST_SET_VRING_KICK comes
+	 * lastly because vhost depends on this msg to judge if
+	 * virtio is ready.
+	 */
+	file.fd = kickfd;
+	vhost_call(dev->vhostfd, dev->type, VHOST_MSG_SET_VRING_KICK, &file);
+	dev->kickfds[queue_sel] = kickfd;
+
+	return 0;
+}
+
+int
+virtio_user_start_device(struct virtio_user_dev *dev)
+{
+	uint64_t features;
+	uint32_t i, queue_sel;
+	int ret;
+
+	/* construct memory region inside each implementation */
+	ret = vhost_call(dev->vhostfd, dev->type,
+			 VHOST_MSG_SET_MEM_TABLE, NULL);
+	if (ret < 0)
+		goto error;
+
+	for (i = 0; i < dev->queue_pairs; ++i) {
+		queue_sel = 2 * i + VTNET_SQ_RQ_QUEUE_IDX;
+		if (virtio_user_kick_queue(dev, queue_sel) < 0) {
+			PMD_DRV_LOG(INFO, "kick rx vq fails: %u", i);
+			goto error;
+		}
+	}
+	for (i = 0; i < dev->queue_pairs; ++i) {
+		queue_sel = 2 * i + VTNET_SQ_TQ_QUEUE_IDX;
+		if (virtio_user_kick_queue(dev, queue_sel) < 0) {
+			PMD_DRV_LOG(INFO, "kick tx vq fails: %u", i);
+			goto error;
+		}
+	}
+
+	/* After setup all virtqueues, we need to set_features so that
+	 * these features can be set into each virtqueue in vhost side.
+	 * And before that, make sure VIRTIO_NET_F_MAC is stripped.
+	 */
+	features = dev->features;
+	features &= ~(1ull << VIRTIO_NET_F_MAC);
+	ret = vhost_call(dev->vhostfd, dev->type,
+			 VHOST_MSG_SET_FEATURES, &features);
+	if (ret < 0)
+		goto error;
+	PMD_DRV_LOG(INFO, "set features: %" PRIx64, features);
+
+	if (dev->type == VHOST_USER)
+		return 0;
+
+	/* It is tricky here, but so far we have to do that */
+	ret = vhost_kernel_post(dev->vhostfd, dev->tapfd, features,
+				dev->queue_pairs * 2);
+	if (ret == 0)
+		return 0;
+error:
+	/* TODO: free resource here or caller to check */
+	return -1;
+}
+
+int virtio_user_stop_device(struct virtio_user_dev *dev)
+{
+	return vhost_call(dev->vhostfd, dev->type, VHOST_MSG_RESET_OWNER, NULL);
+}
+
diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.h b/drivers/net/virtio/virtio_user/virtio_user_dev.h
new file mode 100644
index 0000000..8ca0095
--- /dev/null
+++ b/drivers/net/virtio/virtio_user/virtio_user_dev.h
@@ -0,0 +1,60 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2010-2016 Intel Corporation. All rights reserved.
+ *   All rights reserved.
+ *
+ *   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.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _VIRTIO_USER_DEV_H
+#define _VIRTIO_USER_DEV_H
+
+#include <limits.h>
+#include "../virtio_pci.h"
+
+struct virtio_user_dev {
+	int		type; /* VHOST_KERNEL or VHOST_USER */
+	int		vhostfd;
+	int		tapfd; /* only used in vhost kernel */
+	int		callfds[VIRTIO_MAX_VIRTQUEUES * 2 + 1];
+	int		kickfds[VIRTIO_MAX_VIRTQUEUES * 2 + 1];
+	int		mac_specified;
+	uint32_t	max_queue_pairs;
+	uint32_t	queue_pairs;
+	uint32_t	queue_size;
+	uint64_t	features;
+	uint8_t		status;
+	uint8_t		mac_addr[ETHER_ADDR_LEN];
+	char		path[PATH_MAX];
+	struct vring	vrings[VIRTIO_MAX_VIRTQUEUES * 2 + 1];
+};
+
+int virtio_user_start_device(struct virtio_user_dev *dev);
+int virtio_user_stop_device(struct virtio_user_dev *dev);
+
+#endif
-- 
2.1.4