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				 (1ULL << VIRTIO_NET_F_MTU) | \
 31				 (1ULL << VIRTIO_NET_F_CTRL_VQ) | \
 32				 (1ULL << VIRTIO_NET_F_CTRL_MAC_ADDR))
 33
 34/* 3 virtqueues, 2 address spaces, 2 virtqueue groups */
 35#define VDPASIM_NET_VQ_NUM	3
 36#define VDPASIM_NET_AS_NUM	2
 37#define VDPASIM_NET_GROUP_NUM	2
 38
 39static void vdpasim_net_complete(struct vdpasim_virtqueue *vq, size_t len)
 40{
 41	/* Make sure data is wrote before advancing index */
 42	smp_wmb();
 43
 44	vringh_complete_iotlb(&vq->vring, vq->head, len);
 45
 46	/* Make sure used is visible before rasing the interrupt. */
 47	smp_wmb();
 48
 49	local_bh_disable();
 50	if (vringh_need_notify_iotlb(&vq->vring) > 0)
 51		vringh_notify(&vq->vring);
 52	local_bh_enable();
 53}
 54
 55static bool receive_filter(struct vdpasim *vdpasim, size_t len)
 56{
 57	bool modern = vdpasim->features & (1ULL << VIRTIO_F_VERSION_1);
 58	size_t hdr_len = modern ? sizeof(struct virtio_net_hdr_v1) :
 59				  sizeof(struct virtio_net_hdr);
 60	struct virtio_net_config *vio_config = vdpasim->config;
 61
 62	if (len < ETH_ALEN + hdr_len)
 63		return false;
 64
 65	if (is_broadcast_ether_addr(vdpasim->buffer + hdr_len) ||
 66	    is_multicast_ether_addr(vdpasim->buffer + hdr_len))
 67		return true;
 68	if (!strncmp(vdpasim->buffer + hdr_len, vio_config->mac, ETH_ALEN))
 69		return true;
 70
 71	return false;
 72}
 73
 74static virtio_net_ctrl_ack vdpasim_handle_ctrl_mac(struct vdpasim *vdpasim,
 75						   u8 cmd)
 76{
 77	struct virtio_net_config *vio_config = vdpasim->config;
 78	struct vdpasim_virtqueue *cvq = &vdpasim->vqs[2];
 79	virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
 80	size_t read;
 81
 82	switch (cmd) {
 83	case VIRTIO_NET_CTRL_MAC_ADDR_SET:
 84		read = vringh_iov_pull_iotlb(&cvq->vring, &cvq->in_iov,
 85					     vio_config->mac, ETH_ALEN);
 86		if (read == ETH_ALEN)
 87			status = VIRTIO_NET_OK;
 88		break;
 89	default:
 90		break;
 91	}
 92
 93	return status;
 94}
 95
 96static void vdpasim_handle_cvq(struct vdpasim *vdpasim)
 97{
 98	struct vdpasim_virtqueue *cvq = &vdpasim->vqs[2];
 99	virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
100	struct virtio_net_ctrl_hdr ctrl;
101	size_t read, write;
102	int err;
103
104	if (!(vdpasim->features & (1ULL << VIRTIO_NET_F_CTRL_VQ)))
105		return;
106
107	if (!cvq->ready)
108		return;
109
110	while (true) {
111		err = vringh_getdesc_iotlb(&cvq->vring, &cvq->in_iov,
112					   &cvq->out_iov,
113					   &cvq->head, GFP_ATOMIC);
114		if (err <= 0)
115			break;
116
117		read = vringh_iov_pull_iotlb(&cvq->vring, &cvq->in_iov, &ctrl,
118					     sizeof(ctrl));
119		if (read != sizeof(ctrl))
120			break;
121
122		switch (ctrl.class) {
123		case VIRTIO_NET_CTRL_MAC:
124			status = vdpasim_handle_ctrl_mac(vdpasim, ctrl.cmd);
125			break;
126		default:
127			break;
128		}
129
130		/* Make sure data is wrote before advancing index */
131		smp_wmb();
132
133		write = vringh_iov_push_iotlb(&cvq->vring, &cvq->out_iov,
134					      &status, sizeof(status));
135		vringh_complete_iotlb(&cvq->vring, cvq->head, write);
136		vringh_kiov_cleanup(&cvq->in_iov);
137		vringh_kiov_cleanup(&cvq->out_iov);
138
139		/* Make sure used is visible before rasing the interrupt. */
140		smp_wmb();
141
142		local_bh_disable();
143		if (cvq->cb)
144			cvq->cb(cvq->private);
145		local_bh_enable();
146	}
147}
148
149static void vdpasim_net_work(struct work_struct *work)
150{
151	struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
152	struct vdpasim_virtqueue *txq = &vdpasim->vqs[1];
153	struct vdpasim_virtqueue *rxq = &vdpasim->vqs[0];
154	ssize_t read, write;
155	int pkts = 0;
156	int err;
157
158	spin_lock(&vdpasim->lock);
159
160	if (!vdpasim->running)
161		goto out;
162
163	if (!(vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK))
164		goto out;
165
166	vdpasim_handle_cvq(vdpasim);
167
168	if (!txq->ready || !rxq->ready)
169		goto out;
170
171	while (true) {
172		err = vringh_getdesc_iotlb(&txq->vring, &txq->out_iov, NULL,
173					   &txq->head, GFP_ATOMIC);
174		if (err <= 0)
175			break;
176
177		read = vringh_iov_pull_iotlb(&txq->vring, &txq->out_iov,
178					     vdpasim->buffer,
179					     PAGE_SIZE);
180
181		if (!receive_filter(vdpasim, read)) {
182			vdpasim_net_complete(txq, 0);
183			continue;
184		}
185
186		err = vringh_getdesc_iotlb(&rxq->vring, NULL, &rxq->in_iov,
187					   &rxq->head, GFP_ATOMIC);
188		if (err <= 0) {
189			vdpasim_net_complete(txq, 0);
190			break;
191		}
192
193		write = vringh_iov_push_iotlb(&rxq->vring, &rxq->in_iov,
194					      vdpasim->buffer, read);
195		if (write <= 0)
196			break;
197
198		vdpasim_net_complete(txq, 0);
199		vdpasim_net_complete(rxq, write);
200
201		if (++pkts > 4) {
202			schedule_work(&vdpasim->work);
203			goto out;
204		}
205	}
206
207out:
208	spin_unlock(&vdpasim->lock);
209}
210
211static void vdpasim_net_get_config(struct vdpasim *vdpasim, void *config)
212{
213	struct virtio_net_config *net_config = config;
214
215	net_config->status = cpu_to_vdpasim16(vdpasim, VIRTIO_NET_S_LINK_UP);
216}
217
218static void vdpasim_net_setup_config(struct vdpasim *vdpasim,
219				     const struct vdpa_dev_set_config *config)
220{
221	struct virtio_net_config *vio_config = vdpasim->config;
222
223	if (config->mask & (1 << VDPA_ATTR_DEV_NET_CFG_MACADDR))
224		memcpy(vio_config->mac, config->net.mac, ETH_ALEN);
225	if (config->mask & (1 << VDPA_ATTR_DEV_NET_CFG_MTU))
226		vio_config->mtu = cpu_to_vdpasim16(vdpasim, config->net.mtu);
227	else
228		/* Setup default MTU to be 1500 */
229		vio_config->mtu = cpu_to_vdpasim16(vdpasim, 1500);
230}
231
232static void vdpasim_net_mgmtdev_release(struct device *dev)
233{
234}
235
236static struct device vdpasim_net_mgmtdev = {
237	.init_name = "vdpasim_net",
238	.release = vdpasim_net_mgmtdev_release,
239};
240
241static int vdpasim_net_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
242			       const struct vdpa_dev_set_config *config)
243{
244	struct vdpasim_dev_attr dev_attr = {};
245	struct vdpasim *simdev;
246	int ret;
247
248	dev_attr.mgmt_dev = mdev;
249	dev_attr.name = name;
250	dev_attr.id = VIRTIO_ID_NET;
251	dev_attr.supported_features = VDPASIM_NET_FEATURES;
252	dev_attr.nvqs = VDPASIM_NET_VQ_NUM;
253	dev_attr.ngroups = VDPASIM_NET_GROUP_NUM;
254	dev_attr.nas = VDPASIM_NET_AS_NUM;
255	dev_attr.config_size = sizeof(struct virtio_net_config);
256	dev_attr.get_config = vdpasim_net_get_config;
257	dev_attr.work_fn = vdpasim_net_work;
258	dev_attr.buffer_size = PAGE_SIZE;
259
260	simdev = vdpasim_create(&dev_attr, config);
261	if (IS_ERR(simdev))
262		return PTR_ERR(simdev);
263
264	vdpasim_net_setup_config(simdev, config);
265
266	ret = _vdpa_register_device(&simdev->vdpa, VDPASIM_NET_VQ_NUM);
267	if (ret)
268		goto reg_err;
269
270	return 0;
271
272reg_err:
273	put_device(&simdev->vdpa.dev);
274	return ret;
275}
276
277static void vdpasim_net_dev_del(struct vdpa_mgmt_dev *mdev,
278				struct vdpa_device *dev)
279{
280	struct vdpasim *simdev = container_of(dev, struct vdpasim, vdpa);
281
282	_vdpa_unregister_device(&simdev->vdpa);
283}
284
285static const struct vdpa_mgmtdev_ops vdpasim_net_mgmtdev_ops = {
286	.dev_add = vdpasim_net_dev_add,
287	.dev_del = vdpasim_net_dev_del
288};
289
290static struct virtio_device_id id_table[] = {
291	{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
292	{ 0 },
293};
294
295static struct vdpa_mgmt_dev mgmt_dev = {
296	.device = &vdpasim_net_mgmtdev,
297	.id_table = id_table,
298	.ops = &vdpasim_net_mgmtdev_ops,
299	.config_attr_mask = (1 << VDPA_ATTR_DEV_NET_CFG_MACADDR |
300			     1 << VDPA_ATTR_DEV_NET_CFG_MTU |
301		             1 << VDPA_ATTR_DEV_FEATURES),
302	.max_supported_vqs = VDPASIM_NET_VQ_NUM,
303	.supported_features = VDPASIM_NET_FEATURES,
304};
305
306static int __init vdpasim_net_init(void)
307{
308	int ret;
309
310	ret = device_register(&vdpasim_net_mgmtdev);
311	if (ret) {
312		put_device(&vdpasim_net_mgmtdev);
313		return ret;
314	}
315
316	ret = vdpa_mgmtdev_register(&mgmt_dev);
317	if (ret)
318		goto parent_err;
319	return 0;
320
321parent_err:
322	device_unregister(&vdpasim_net_mgmtdev);
323	return ret;
324}
325
326static void __exit vdpasim_net_exit(void)
327{
328	vdpa_mgmtdev_unregister(&mgmt_dev);
329	device_unregister(&vdpasim_net_mgmtdev);
330}
331
332module_init(vdpasim_net_init);
333module_exit(vdpasim_net_exit);
334
335MODULE_VERSION(DRV_VERSION);
336MODULE_LICENSE(DRV_LICENSE);
337MODULE_AUTHOR(DRV_AUTHOR);
338MODULE_DESCRIPTION(DRV_DESC);