1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * VDPA simulator for networking device.
4  *
5  * Copyright (c) 2020, Red Hat Inc. All rights reserved.
6  *     Author: Jason Wang <jasowang@redhat.com>
7  *
8  */
9 
10 #include <linux/init.h>
11 #include <linux/module.h>
12 #include <linux/device.h>
13 #include <linux/kernel.h>
14 #include <linux/sched.h>
15 #include <linux/etherdevice.h>
16 #include <linux/vringh.h>
17 #include <linux/vdpa.h>
18 #include <uapi/linux/virtio_net.h>
19 #include <uapi/linux/vdpa.h>
20 
21 #include "vdpa_sim.h"
22 
23 #define DRV_VERSION  "0.1"
24 #define DRV_AUTHOR   "Jason Wang <jasowang@redhat.com>"
25 #define DRV_DESC     "vDPA Device Simulator for networking device"
26 #define DRV_LICENSE  "GPL v2"
27 
28 #define VDPASIM_NET_FEATURES	(VDPASIM_FEATURES | \
29 				 (1ULL << VIRTIO_NET_F_MAC))
30 
31 #define VDPASIM_NET_VQ_NUM	2
32 
33 static void vdpasim_net_work(struct work_struct *work)
34 {
35 	struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
36 	struct vdpasim_virtqueue *txq = &vdpasim->vqs[1];
37 	struct vdpasim_virtqueue *rxq = &vdpasim->vqs[0];
38 	ssize_t read, write;
39 	size_t total_write;
40 	int pkts = 0;
41 	int err;
42 
43 	spin_lock(&vdpasim->lock);
44 
45 	if (!(vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK))
46 		goto out;
47 
48 	if (!txq->ready || !rxq->ready)
49 		goto out;
50 
51 	while (true) {
52 		total_write = 0;
53 		err = vringh_getdesc_iotlb(&txq->vring, &txq->out_iov, NULL,
54 					   &txq->head, GFP_ATOMIC);
55 		if (err <= 0)
56 			break;
57 
58 		err = vringh_getdesc_iotlb(&rxq->vring, NULL, &rxq->in_iov,
59 					   &rxq->head, GFP_ATOMIC);
60 		if (err <= 0) {
61 			vringh_complete_iotlb(&txq->vring, txq->head, 0);
62 			break;
63 		}
64 
65 		while (true) {
66 			read = vringh_iov_pull_iotlb(&txq->vring, &txq->out_iov,
67 						     vdpasim->buffer,
68 						     PAGE_SIZE);
69 			if (read <= 0)
70 				break;
71 
72 			write = vringh_iov_push_iotlb(&rxq->vring, &rxq->in_iov,
73 						      vdpasim->buffer, read);
74 			if (write <= 0)
75 				break;
76 
77 			total_write += write;
78 		}
79 
80 		/* Make sure data is wrote before advancing index */
81 		smp_wmb();
82 
83 		vringh_complete_iotlb(&txq->vring, txq->head, 0);
84 		vringh_complete_iotlb(&rxq->vring, rxq->head, total_write);
85 
86 		/* Make sure used is visible before rasing the interrupt. */
87 		smp_wmb();
88 
89 		local_bh_disable();
90 		if (vringh_need_notify_iotlb(&txq->vring) > 0)
91 			vringh_notify(&txq->vring);
92 		if (vringh_need_notify_iotlb(&rxq->vring) > 0)
93 			vringh_notify(&rxq->vring);
94 		local_bh_enable();
95 
96 		if (++pkts > 4) {
97 			schedule_work(&vdpasim->work);
98 			goto out;
99 		}
100 	}
101 
102 out:
103 	spin_unlock(&vdpasim->lock);
104 }
105 
106 static void vdpasim_net_get_config(struct vdpasim *vdpasim, void *config)
107 {
108 	struct virtio_net_config *net_config = config;
109 
110 	net_config->status = cpu_to_vdpasim16(vdpasim, VIRTIO_NET_S_LINK_UP);
111 }
112 
113 static void vdpasim_net_setup_config(struct vdpasim *vdpasim,
114 				     const struct vdpa_dev_set_config *config)
115 {
116 	struct virtio_net_config *vio_config = vdpasim->config;
117 
118 	if (config->mask & (1 << VDPA_ATTR_DEV_NET_CFG_MACADDR))
119 		memcpy(vio_config->mac, config->net.mac, ETH_ALEN);
120 	if (config->mask & (1 << VDPA_ATTR_DEV_NET_CFG_MTU))
121 		vio_config->mtu = cpu_to_vdpasim16(vdpasim, config->net.mtu);
122 	else
123 		/* Setup default MTU to be 1500 */
124 		vio_config->mtu = cpu_to_vdpasim16(vdpasim, 1500);
125 }
126 
127 static void vdpasim_net_mgmtdev_release(struct device *dev)
128 {
129 }
130 
131 static struct device vdpasim_net_mgmtdev = {
132 	.init_name = "vdpasim_net",
133 	.release = vdpasim_net_mgmtdev_release,
134 };
135 
136 static int vdpasim_net_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
137 			       const struct vdpa_dev_set_config *config)
138 {
139 	struct vdpasim_dev_attr dev_attr = {};
140 	struct vdpasim *simdev;
141 	int ret;
142 
143 	dev_attr.mgmt_dev = mdev;
144 	dev_attr.name = name;
145 	dev_attr.id = VIRTIO_ID_NET;
146 	dev_attr.supported_features = VDPASIM_NET_FEATURES;
147 	dev_attr.nvqs = VDPASIM_NET_VQ_NUM;
148 	dev_attr.config_size = sizeof(struct virtio_net_config);
149 	dev_attr.get_config = vdpasim_net_get_config;
150 	dev_attr.work_fn = vdpasim_net_work;
151 	dev_attr.buffer_size = PAGE_SIZE;
152 
153 	simdev = vdpasim_create(&dev_attr);
154 	if (IS_ERR(simdev))
155 		return PTR_ERR(simdev);
156 
157 	vdpasim_net_setup_config(simdev, config);
158 
159 	ret = _vdpa_register_device(&simdev->vdpa, VDPASIM_NET_VQ_NUM);
160 	if (ret)
161 		goto reg_err;
162 
163 	return 0;
164 
165 reg_err:
166 	put_device(&simdev->vdpa.dev);
167 	return ret;
168 }
169 
170 static void vdpasim_net_dev_del(struct vdpa_mgmt_dev *mdev,
171 				struct vdpa_device *dev)
172 {
173 	struct vdpasim *simdev = container_of(dev, struct vdpasim, vdpa);
174 
175 	_vdpa_unregister_device(&simdev->vdpa);
176 }
177 
178 static const struct vdpa_mgmtdev_ops vdpasim_net_mgmtdev_ops = {
179 	.dev_add = vdpasim_net_dev_add,
180 	.dev_del = vdpasim_net_dev_del
181 };
182 
183 static struct virtio_device_id id_table[] = {
184 	{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
185 	{ 0 },
186 };
187 
188 static struct vdpa_mgmt_dev mgmt_dev = {
189 	.device = &vdpasim_net_mgmtdev,
190 	.id_table = id_table,
191 	.ops = &vdpasim_net_mgmtdev_ops,
192 	.config_attr_mask = (1 << VDPA_ATTR_DEV_NET_CFG_MACADDR |
193 			     1 << VDPA_ATTR_DEV_NET_CFG_MTU),
194 	.max_supported_vqs = VDPASIM_NET_VQ_NUM,
195 	.supported_features = VDPASIM_NET_FEATURES,
196 };
197 
198 static int __init vdpasim_net_init(void)
199 {
200 	int ret;
201 
202 	ret = device_register(&vdpasim_net_mgmtdev);
203 	if (ret)
204 		return ret;
205 
206 	ret = vdpa_mgmtdev_register(&mgmt_dev);
207 	if (ret)
208 		goto parent_err;
209 	return 0;
210 
211 parent_err:
212 	device_unregister(&vdpasim_net_mgmtdev);
213 	return ret;
214 }
215 
216 static void __exit vdpasim_net_exit(void)
217 {
218 	vdpa_mgmtdev_unregister(&mgmt_dev);
219 	device_unregister(&vdpasim_net_mgmtdev);
220 }
221 
222 module_init(vdpasim_net_init);
223 module_exit(vdpasim_net_exit);
224 
225 MODULE_VERSION(DRV_VERSION);
226 MODULE_LICENSE(DRV_LICENSE);
227 MODULE_AUTHOR(DRV_AUTHOR);
228 MODULE_DESCRIPTION(DRV_DESC);
229