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 
20 #include "vdpa_sim.h"
21 
22 #define DRV_VERSION  "0.1"
23 #define DRV_AUTHOR   "Jason Wang <jasowang@redhat.com>"
24 #define DRV_DESC     "vDPA Device Simulator for networking device"
25 #define DRV_LICENSE  "GPL v2"
26 
27 #define VDPASIM_NET_FEATURES	(VDPASIM_FEATURES | \
28 				 (1ULL << VIRTIO_NET_F_MAC))
29 
30 #define VDPASIM_NET_VQ_NUM	2
31 
32 static char *macaddr;
33 module_param(macaddr, charp, 0);
34 MODULE_PARM_DESC(macaddr, "Ethernet MAC address");
35 
36 static u8 macaddr_buf[ETH_ALEN];
37 
38 static void vdpasim_net_work(struct work_struct *work)
39 {
40 	struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
41 	struct vdpasim_virtqueue *txq = &vdpasim->vqs[1];
42 	struct vdpasim_virtqueue *rxq = &vdpasim->vqs[0];
43 	ssize_t read, write;
44 	size_t total_write;
45 	int pkts = 0;
46 	int err;
47 
48 	spin_lock(&vdpasim->lock);
49 
50 	if (!(vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK))
51 		goto out;
52 
53 	if (!txq->ready || !rxq->ready)
54 		goto out;
55 
56 	while (true) {
57 		total_write = 0;
58 		err = vringh_getdesc_iotlb(&txq->vring, &txq->out_iov, NULL,
59 					   &txq->head, GFP_ATOMIC);
60 		if (err <= 0)
61 			break;
62 
63 		err = vringh_getdesc_iotlb(&rxq->vring, NULL, &rxq->in_iov,
64 					   &rxq->head, GFP_ATOMIC);
65 		if (err <= 0) {
66 			vringh_complete_iotlb(&txq->vring, txq->head, 0);
67 			break;
68 		}
69 
70 		while (true) {
71 			read = vringh_iov_pull_iotlb(&txq->vring, &txq->out_iov,
72 						     vdpasim->buffer,
73 						     PAGE_SIZE);
74 			if (read <= 0)
75 				break;
76 
77 			write = vringh_iov_push_iotlb(&rxq->vring, &rxq->in_iov,
78 						      vdpasim->buffer, read);
79 			if (write <= 0)
80 				break;
81 
82 			total_write += write;
83 		}
84 
85 		/* Make sure data is wrote before advancing index */
86 		smp_wmb();
87 
88 		vringh_complete_iotlb(&txq->vring, txq->head, 0);
89 		vringh_complete_iotlb(&rxq->vring, rxq->head, total_write);
90 
91 		/* Make sure used is visible before rasing the interrupt. */
92 		smp_wmb();
93 
94 		local_bh_disable();
95 		if (vringh_need_notify_iotlb(&txq->vring) > 0)
96 			vringh_notify(&txq->vring);
97 		if (vringh_need_notify_iotlb(&rxq->vring) > 0)
98 			vringh_notify(&rxq->vring);
99 		local_bh_enable();
100 
101 		if (++pkts > 4) {
102 			schedule_work(&vdpasim->work);
103 			goto out;
104 		}
105 	}
106 
107 out:
108 	spin_unlock(&vdpasim->lock);
109 }
110 
111 static void vdpasim_net_get_config(struct vdpasim *vdpasim, void *config)
112 {
113 	struct virtio_net_config *net_config = config;
114 
115 	net_config->mtu = cpu_to_vdpasim16(vdpasim, 1500);
116 	net_config->status = cpu_to_vdpasim16(vdpasim, VIRTIO_NET_S_LINK_UP);
117 	memcpy(net_config->mac, macaddr_buf, ETH_ALEN);
118 }
119 
120 static void vdpasim_net_mgmtdev_release(struct device *dev)
121 {
122 }
123 
124 static struct device vdpasim_net_mgmtdev = {
125 	.init_name = "vdpasim_net",
126 	.release = vdpasim_net_mgmtdev_release,
127 };
128 
129 static int vdpasim_net_dev_add(struct vdpa_mgmt_dev *mdev, const char *name)
130 {
131 	struct vdpasim_dev_attr dev_attr = {};
132 	struct vdpasim *simdev;
133 	int ret;
134 
135 	dev_attr.mgmt_dev = mdev;
136 	dev_attr.name = name;
137 	dev_attr.id = VIRTIO_ID_NET;
138 	dev_attr.supported_features = VDPASIM_NET_FEATURES;
139 	dev_attr.nvqs = VDPASIM_NET_VQ_NUM;
140 	dev_attr.config_size = sizeof(struct virtio_net_config);
141 	dev_attr.get_config = vdpasim_net_get_config;
142 	dev_attr.work_fn = vdpasim_net_work;
143 	dev_attr.buffer_size = PAGE_SIZE;
144 
145 	simdev = vdpasim_create(&dev_attr);
146 	if (IS_ERR(simdev))
147 		return PTR_ERR(simdev);
148 
149 	ret = _vdpa_register_device(&simdev->vdpa, VDPASIM_NET_VQ_NUM);
150 	if (ret)
151 		goto reg_err;
152 
153 	return 0;
154 
155 reg_err:
156 	put_device(&simdev->vdpa.dev);
157 	return ret;
158 }
159 
160 static void vdpasim_net_dev_del(struct vdpa_mgmt_dev *mdev,
161 				struct vdpa_device *dev)
162 {
163 	struct vdpasim *simdev = container_of(dev, struct vdpasim, vdpa);
164 
165 	_vdpa_unregister_device(&simdev->vdpa);
166 }
167 
168 static const struct vdpa_mgmtdev_ops vdpasim_net_mgmtdev_ops = {
169 	.dev_add = vdpasim_net_dev_add,
170 	.dev_del = vdpasim_net_dev_del
171 };
172 
173 static struct virtio_device_id id_table[] = {
174 	{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
175 	{ 0 },
176 };
177 
178 static struct vdpa_mgmt_dev mgmt_dev = {
179 	.device = &vdpasim_net_mgmtdev,
180 	.id_table = id_table,
181 	.ops = &vdpasim_net_mgmtdev_ops,
182 };
183 
184 static int __init vdpasim_net_init(void)
185 {
186 	int ret;
187 
188 	if (macaddr) {
189 		mac_pton(macaddr, macaddr_buf);
190 		if (!is_valid_ether_addr(macaddr_buf))
191 			return -EADDRNOTAVAIL;
192 	} else {
193 		eth_random_addr(macaddr_buf);
194 	}
195 
196 	ret = device_register(&vdpasim_net_mgmtdev);
197 	if (ret)
198 		return ret;
199 
200 	ret = vdpa_mgmtdev_register(&mgmt_dev);
201 	if (ret)
202 		goto parent_err;
203 	return 0;
204 
205 parent_err:
206 	device_unregister(&vdpasim_net_mgmtdev);
207 	return ret;
208 }
209 
210 static void __exit vdpasim_net_exit(void)
211 {
212 	vdpa_mgmtdev_unregister(&mgmt_dev);
213 	device_unregister(&vdpasim_net_mgmtdev);
214 }
215 
216 module_init(vdpasim_net_init);
217 module_exit(vdpasim_net_exit);
218 
219 MODULE_VERSION(DRV_VERSION);
220 MODULE_LICENSE(DRV_LICENSE);
221 MODULE_AUTHOR(DRV_AUTHOR);
222 MODULE_DESCRIPTION(DRV_DESC);
223