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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/blkdev.h>
16#include <linux/vringh.h>
17#include <linux/vdpa.h>
18#include <uapi/linux/virtio_blk.h>
19
20#include "vdpa_sim.h"
21
22#define DRV_VERSION "0.1"
23#define DRV_AUTHOR "Max Gurtovoy <mgurtovoy@nvidia.com>"
24#define DRV_DESC "vDPA Device Simulator for block device"
25#define DRV_LICENSE "GPL v2"
26
27#define VDPASIM_BLK_FEATURES (VDPASIM_FEATURES | \
28 (1ULL << VIRTIO_BLK_F_SIZE_MAX) | \
29 (1ULL << VIRTIO_BLK_F_SEG_MAX) | \
30 (1ULL << VIRTIO_BLK_F_BLK_SIZE) | \
31 (1ULL << VIRTIO_BLK_F_TOPOLOGY) | \
32 (1ULL << VIRTIO_BLK_F_MQ))
33
34#define VDPASIM_BLK_CAPACITY 0x40000
35#define VDPASIM_BLK_SIZE_MAX 0x1000
36#define VDPASIM_BLK_SEG_MAX 32
37#define VDPASIM_BLK_VQ_NUM 1
38
39static char vdpasim_blk_id[VIRTIO_BLK_ID_BYTES] = "vdpa_blk_sim";
40
41static bool vdpasim_blk_check_range(u64 start_sector, size_t range_size)
42{
43 u64 range_sectors = range_size >> SECTOR_SHIFT;
44
45 if (range_size > VDPASIM_BLK_SIZE_MAX * VDPASIM_BLK_SEG_MAX)
46 return false;
47
48 if (start_sector > VDPASIM_BLK_CAPACITY)
49 return false;
50
51 if (range_sectors > VDPASIM_BLK_CAPACITY - start_sector)
52 return false;
53
54 return true;
55}
56
57
58
59
60
61static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim,
62 struct vdpasim_virtqueue *vq)
63{
64 size_t pushed = 0, to_pull, to_push;
65 struct virtio_blk_outhdr hdr;
66 ssize_t bytes;
67 loff_t offset;
68 u64 sector;
69 u8 status;
70 u32 type;
71 int ret;
72
73 ret = vringh_getdesc_iotlb(&vq->vring, &vq->out_iov, &vq->in_iov,
74 &vq->head, GFP_ATOMIC);
75 if (ret != 1)
76 return false;
77
78 if (vq->out_iov.used < 1 || vq->in_iov.used < 1) {
79 dev_err(&vdpasim->vdpa.dev, "missing headers - out_iov: %u in_iov %u\n",
80 vq->out_iov.used, vq->in_iov.used);
81 return false;
82 }
83
84 if (vq->in_iov.iov[vq->in_iov.used - 1].iov_len < 1) {
85 dev_err(&vdpasim->vdpa.dev, "request in header too short\n");
86 return false;
87 }
88
89
90
91
92 to_push = vringh_kiov_length(&vq->in_iov) - 1;
93
94 to_pull = vringh_kiov_length(&vq->out_iov);
95
96 bytes = vringh_iov_pull_iotlb(&vq->vring, &vq->out_iov, &hdr,
97 sizeof(hdr));
98 if (bytes != sizeof(hdr)) {
99 dev_err(&vdpasim->vdpa.dev, "request out header too short\n");
100 return false;
101 }
102
103 to_pull -= bytes;
104
105 type = vdpasim32_to_cpu(vdpasim, hdr.type);
106 sector = vdpasim64_to_cpu(vdpasim, hdr.sector);
107 offset = sector << SECTOR_SHIFT;
108 status = VIRTIO_BLK_S_OK;
109
110 switch (type) {
111 case VIRTIO_BLK_T_IN:
112 if (!vdpasim_blk_check_range(sector, to_push)) {
113 dev_err(&vdpasim->vdpa.dev,
114 "reading over the capacity - offset: 0x%llx len: 0x%zx\n",
115 offset, to_push);
116 status = VIRTIO_BLK_S_IOERR;
117 break;
118 }
119
120 bytes = vringh_iov_push_iotlb(&vq->vring, &vq->in_iov,
121 vdpasim->buffer + offset,
122 to_push);
123 if (bytes < 0) {
124 dev_err(&vdpasim->vdpa.dev,
125 "vringh_iov_push_iotlb() error: %zd offset: 0x%llx len: 0x%zx\n",
126 bytes, offset, to_push);
127 status = VIRTIO_BLK_S_IOERR;
128 break;
129 }
130
131 pushed += bytes;
132 break;
133
134 case VIRTIO_BLK_T_OUT:
135 if (!vdpasim_blk_check_range(sector, to_pull)) {
136 dev_err(&vdpasim->vdpa.dev,
137 "writing over the capacity - offset: 0x%llx len: 0x%zx\n",
138 offset, to_pull);
139 status = VIRTIO_BLK_S_IOERR;
140 break;
141 }
142
143 bytes = vringh_iov_pull_iotlb(&vq->vring, &vq->out_iov,
144 vdpasim->buffer + offset,
145 to_pull);
146 if (bytes < 0) {
147 dev_err(&vdpasim->vdpa.dev,
148 "vringh_iov_pull_iotlb() error: %zd offset: 0x%llx len: 0x%zx\n",
149 bytes, offset, to_pull);
150 status = VIRTIO_BLK_S_IOERR;
151 break;
152 }
153 break;
154
155 case VIRTIO_BLK_T_GET_ID:
156 bytes = vringh_iov_push_iotlb(&vq->vring, &vq->in_iov,
157 vdpasim_blk_id,
158 VIRTIO_BLK_ID_BYTES);
159 if (bytes < 0) {
160 dev_err(&vdpasim->vdpa.dev,
161 "vringh_iov_push_iotlb() error: %zd\n", bytes);
162 status = VIRTIO_BLK_S_IOERR;
163 break;
164 }
165
166 pushed += bytes;
167 break;
168
169 default:
170 dev_warn(&vdpasim->vdpa.dev,
171 "Unsupported request type %d\n", type);
172 status = VIRTIO_BLK_S_IOERR;
173 break;
174 }
175
176
177
178
179 if (to_push - pushed > 0)
180 vringh_kiov_advance(&vq->in_iov, to_push - pushed);
181
182
183 bytes = vringh_iov_push_iotlb(&vq->vring, &vq->in_iov, &status, 1);
184 if (bytes != 1)
185 return false;
186
187 pushed += bytes;
188
189
190 smp_wmb();
191
192 vringh_complete_iotlb(&vq->vring, vq->head, pushed);
193
194 return true;
195}
196
197static void vdpasim_blk_work(struct work_struct *work)
198{
199 struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
200 int i;
201
202 spin_lock(&vdpasim->lock);
203
204 if (!(vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK))
205 goto out;
206
207 for (i = 0; i < VDPASIM_BLK_VQ_NUM; i++) {
208 struct vdpasim_virtqueue *vq = &vdpasim->vqs[i];
209
210 if (!vq->ready)
211 continue;
212
213 while (vdpasim_blk_handle_req(vdpasim, vq)) {
214
215 smp_wmb();
216
217 local_bh_disable();
218 if (vringh_need_notify_iotlb(&vq->vring) > 0)
219 vringh_notify(&vq->vring);
220 local_bh_enable();
221 }
222 }
223out:
224 spin_unlock(&vdpasim->lock);
225}
226
227static void vdpasim_blk_get_config(struct vdpasim *vdpasim, void *config)
228{
229 struct virtio_blk_config *blk_config = config;
230
231 memset(config, 0, sizeof(struct virtio_blk_config));
232
233 blk_config->capacity = cpu_to_vdpasim64(vdpasim, VDPASIM_BLK_CAPACITY);
234 blk_config->size_max = cpu_to_vdpasim32(vdpasim, VDPASIM_BLK_SIZE_MAX);
235 blk_config->seg_max = cpu_to_vdpasim32(vdpasim, VDPASIM_BLK_SEG_MAX);
236 blk_config->num_queues = cpu_to_vdpasim16(vdpasim, VDPASIM_BLK_VQ_NUM);
237 blk_config->min_io_size = cpu_to_vdpasim16(vdpasim, 1);
238 blk_config->opt_io_size = cpu_to_vdpasim32(vdpasim, 1);
239 blk_config->blk_size = cpu_to_vdpasim32(vdpasim, SECTOR_SIZE);
240}
241
242static void vdpasim_blk_mgmtdev_release(struct device *dev)
243{
244}
245
246static struct device vdpasim_blk_mgmtdev = {
247 .init_name = "vdpasim_blk",
248 .release = vdpasim_blk_mgmtdev_release,
249};
250
251static int vdpasim_blk_dev_add(struct vdpa_mgmt_dev *mdev, const char *name)
252{
253 struct vdpasim_dev_attr dev_attr = {};
254 struct vdpasim *simdev;
255 int ret;
256
257 dev_attr.mgmt_dev = mdev;
258 dev_attr.name = name;
259 dev_attr.id = VIRTIO_ID_BLOCK;
260 dev_attr.supported_features = VDPASIM_BLK_FEATURES;
261 dev_attr.nvqs = VDPASIM_BLK_VQ_NUM;
262 dev_attr.config_size = sizeof(struct virtio_blk_config);
263 dev_attr.get_config = vdpasim_blk_get_config;
264 dev_attr.work_fn = vdpasim_blk_work;
265 dev_attr.buffer_size = VDPASIM_BLK_CAPACITY << SECTOR_SHIFT;
266
267 simdev = vdpasim_create(&dev_attr);
268 if (IS_ERR(simdev))
269 return PTR_ERR(simdev);
270
271 ret = _vdpa_register_device(&simdev->vdpa, VDPASIM_BLK_VQ_NUM);
272 if (ret)
273 goto put_dev;
274
275 return 0;
276
277put_dev:
278 put_device(&simdev->vdpa.dev);
279 return ret;
280}
281
282static void vdpasim_blk_dev_del(struct vdpa_mgmt_dev *mdev,
283 struct vdpa_device *dev)
284{
285 struct vdpasim *simdev = container_of(dev, struct vdpasim, vdpa);
286
287 _vdpa_unregister_device(&simdev->vdpa);
288}
289
290static const struct vdpa_mgmtdev_ops vdpasim_blk_mgmtdev_ops = {
291 .dev_add = vdpasim_blk_dev_add,
292 .dev_del = vdpasim_blk_dev_del
293};
294
295static struct virtio_device_id id_table[] = {
296 { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
297 { 0 },
298};
299
300static struct vdpa_mgmt_dev mgmt_dev = {
301 .device = &vdpasim_blk_mgmtdev,
302 .id_table = id_table,
303 .ops = &vdpasim_blk_mgmtdev_ops,
304};
305
306static int __init vdpasim_blk_init(void)
307{
308 int ret;
309
310 ret = device_register(&vdpasim_blk_mgmtdev);
311 if (ret)
312 return ret;
313
314 ret = vdpa_mgmtdev_register(&mgmt_dev);
315 if (ret)
316 goto parent_err;
317
318 return 0;
319
320parent_err:
321 device_unregister(&vdpasim_blk_mgmtdev);
322 return ret;
323}
324
325static void __exit vdpasim_blk_exit(void)
326{
327 vdpa_mgmtdev_unregister(&mgmt_dev);
328 device_unregister(&vdpasim_blk_mgmtdev);
329}
330
331module_init(vdpasim_blk_init)
332module_exit(vdpasim_blk_exit)
333
334MODULE_VERSION(DRV_VERSION);
335MODULE_LICENSE(DRV_LICENSE);
336MODULE_AUTHOR(DRV_AUTHOR);
337MODULE_DESCRIPTION(DRV_DESC);
338
