1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * uio_hv_generic - generic UIO driver for VMBus
4 *
5 * Copyright (c) 2013-2016 Brocade Communications Systems, Inc.
6 * Copyright (c) 2016, Microsoft Corporation.
7 *
8 * Since the driver does not declare any device ids, you must allocate
9 * id and bind the device to the driver yourself. For example:
10 *
11 * Associate Network GUID with UIO device
12 * # echo "f8615163-df3e-46c5-913f-f2d2f965ed0e" \
13 * > /sys/bus/vmbus/drivers/uio_hv_generic/new_id
14 * Then rebind
15 * # echo -n "ed963694-e847-4b2a-85af-bc9cfc11d6f3" \
16 * > /sys/bus/vmbus/drivers/hv_netvsc/unbind
17 * # echo -n "ed963694-e847-4b2a-85af-bc9cfc11d6f3" \
18 * > /sys/bus/vmbus/drivers/uio_hv_generic/bind
19 */
20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21
22 #include <linux/device.h>
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/uio_driver.h>
26 #include <linux/netdevice.h>
27 #include <linux/if_ether.h>
28 #include <linux/skbuff.h>
29 #include <linux/hyperv.h>
30 #include <linux/vmalloc.h>
31 #include <linux/slab.h>
32
33 #include "../hv/hyperv_vmbus.h"
34
35 #define DRIVER_VERSION "0.02.1"
36 #define DRIVER_AUTHOR "Stephen Hemminger <sthemmin at microsoft.com>"
37 #define DRIVER_DESC "Generic UIO driver for VMBus devices"
38
39 #define HV_RING_SIZE 512 /* pages */
40 #define SEND_BUFFER_SIZE (16 * 1024 * 1024)
41 #define RECV_BUFFER_SIZE (31 * 1024 * 1024)
42
43 /*
44 * List of resources to be mapped to user space
45 * can be extended up to MAX_UIO_MAPS(5) items
46 */
47 enum hv_uio_map {
48 TXRX_RING_MAP = 0,
49 INT_PAGE_MAP,
50 MON_PAGE_MAP,
51 RECV_BUF_MAP,
52 SEND_BUF_MAP
53 };
54
55 struct hv_uio_private_data {
56 struct uio_info info;
57 struct hv_device *device;
58 atomic_t refcnt;
59
60 void *recv_buf;
61 u32 recv_gpadl;
62 char recv_name[32]; /* "recv_4294967295" */
63
64 void *send_buf;
65 u32 send_gpadl;
66 char send_name[32];
67 };
68
69 /*
70 * This is the irqcontrol callback to be registered to uio_info.
71 * It can be used to disable/enable interrupt from user space processes.
72 *
73 * @param info
74 * pointer to uio_info.
75 * @param irq_state
76 * state value. 1 to enable interrupt, 0 to disable interrupt.
77 */
78 static int
hv_uio_irqcontrol(struct uio_info *info, s32 irq_state)79 hv_uio_irqcontrol(struct uio_info *info, s32 irq_state)
80 {
81 struct hv_uio_private_data *pdata = info->priv;
82 struct hv_device *dev = pdata->device;
83
84 dev->channel->inbound.ring_buffer->interrupt_mask = !irq_state;
85 virt_mb();
86
87 return 0;
88 }
89
90 /*
91 * Callback from vmbus_event when something is in inbound ring.
92 */
hv_uio_channel_cb(void *context)93 static void hv_uio_channel_cb(void *context)
94 {
95 struct vmbus_channel *chan = context;
96 struct hv_device *hv_dev = chan->device_obj;
97 struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev);
98
99 chan->inbound.ring_buffer->interrupt_mask = 1;
100 virt_mb();
101
102 uio_event_notify(&pdata->info);
103 }
104
105 /*
106 * Callback from vmbus_event when channel is rescinded.
107 * It is meant for rescind of primary channels only.
108 */
hv_uio_rescind(struct vmbus_channel *channel)109 static void hv_uio_rescind(struct vmbus_channel *channel)
110 {
111 struct hv_device *hv_dev = channel->device_obj;
112 struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev);
113
114 /*
115 * Turn off the interrupt file handle
116 * Next read for event will return -EIO
117 */
118 pdata->info.irq = 0;
119
120 /* Wake up reader */
121 uio_event_notify(&pdata->info);
122 }
123
124 /* Sysfs API to allow mmap of the ring buffers
125 * The ring buffer is allocated as contiguous memory by vmbus_open
126 */
hv_uio_ring_mmap(struct file *filp, struct kobject *kobj, struct bin_attribute *attr, struct vm_area_struct *vma)127 static int hv_uio_ring_mmap(struct file *filp, struct kobject *kobj,
128 struct bin_attribute *attr,
129 struct vm_area_struct *vma)
130 {
131 struct vmbus_channel *channel
132 = container_of(kobj, struct vmbus_channel, kobj);
133 void *ring_buffer = page_address(channel->ringbuffer_page);
134
135 if (channel->state != CHANNEL_OPENED_STATE)
136 return -ENODEV;
137
138 return vm_iomap_memory(vma, virt_to_phys(ring_buffer),
139 channel->ringbuffer_pagecount << PAGE_SHIFT);
140 }
141
142 static const struct bin_attribute ring_buffer_bin_attr = {
143 .attr = {
144 .name = "ring",
145 .mode = 0600,
146 },
147 .size = 2 * HV_RING_SIZE * PAGE_SIZE,
148 .mmap = hv_uio_ring_mmap,
149 };
150
151 /* Callback from VMBUS subsystem when new channel created. */
152 static void
hv_uio_new_channel(struct vmbus_channel *new_sc)153 hv_uio_new_channel(struct vmbus_channel *new_sc)
154 {
155 struct hv_device *hv_dev = new_sc->primary_channel->device_obj;
156 struct device *device = &hv_dev->device;
157 const size_t ring_bytes = HV_RING_SIZE * PAGE_SIZE;
158 int ret;
159
160 /* Create host communication ring */
161 ret = vmbus_open(new_sc, ring_bytes, ring_bytes, NULL, 0,
162 hv_uio_channel_cb, new_sc);
163 if (ret) {
164 dev_err(device, "vmbus_open subchannel failed: %d\n", ret);
165 return;
166 }
167
168 /* Disable interrupts on sub channel */
169 new_sc->inbound.ring_buffer->interrupt_mask = 1;
170 set_channel_read_mode(new_sc, HV_CALL_ISR);
171
172 ret = sysfs_create_bin_file(&new_sc->kobj, &ring_buffer_bin_attr);
173 if (ret) {
174 dev_err(device, "sysfs create ring bin file failed; %d\n", ret);
175 vmbus_close(new_sc);
176 }
177 }
178
179 /* free the reserved buffers for send and receive */
180 static void
hv_uio_cleanup(struct hv_device *dev, struct hv_uio_private_data *pdata)181 hv_uio_cleanup(struct hv_device *dev, struct hv_uio_private_data *pdata)
182 {
183 if (pdata->send_gpadl) {
184 vmbus_teardown_gpadl(dev->channel, pdata->send_gpadl);
185 pdata->send_gpadl = 0;
186 vfree(pdata->send_buf);
187 }
188
189 if (pdata->recv_gpadl) {
190 vmbus_teardown_gpadl(dev->channel, pdata->recv_gpadl);
191 pdata->recv_gpadl = 0;
192 vfree(pdata->recv_buf);
193 }
194 }
195
196 /* VMBus primary channel is opened on first use */
197 static int
hv_uio_open(struct uio_info *info, struct inode *inode)198 hv_uio_open(struct uio_info *info, struct inode *inode)
199 {
200 struct hv_uio_private_data *pdata
201 = container_of(info, struct hv_uio_private_data, info);
202 struct hv_device *dev = pdata->device;
203 int ret;
204
205 if (atomic_inc_return(&pdata->refcnt) != 1)
206 return 0;
207
208 vmbus_set_chn_rescind_callback(dev->channel, hv_uio_rescind);
209 vmbus_set_sc_create_callback(dev->channel, hv_uio_new_channel);
210
211 ret = vmbus_connect_ring(dev->channel,
212 hv_uio_channel_cb, dev->channel);
213 if (ret == 0)
214 dev->channel->inbound.ring_buffer->interrupt_mask = 1;
215 else
216 atomic_dec(&pdata->refcnt);
217
218 return ret;
219 }
220
221 /* VMBus primary channel is closed on last close */
222 static int
hv_uio_release(struct uio_info *info, struct inode *inode)223 hv_uio_release(struct uio_info *info, struct inode *inode)
224 {
225 struct hv_uio_private_data *pdata
226 = container_of(info, struct hv_uio_private_data, info);
227 struct hv_device *dev = pdata->device;
228 int ret = 0;
229
230 if (atomic_dec_and_test(&pdata->refcnt))
231 ret = vmbus_disconnect_ring(dev->channel);
232
233 return ret;
234 }
235
236 static int
hv_uio_probe(struct hv_device *dev, const struct hv_vmbus_device_id *dev_id)237 hv_uio_probe(struct hv_device *dev,
238 const struct hv_vmbus_device_id *dev_id)
239 {
240 struct vmbus_channel *channel = dev->channel;
241 struct hv_uio_private_data *pdata;
242 void *ring_buffer;
243 int ret;
244
245 /* Communicating with host has to be via shared memory not hypercall */
246 if (!channel->offermsg.monitor_allocated) {
247 dev_err(&dev->device, "vmbus channel requires hypercall\n");
248 return -ENOTSUPP;
249 }
250
251 pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
252 if (!pdata)
253 return -ENOMEM;
254
255 ret = vmbus_alloc_ring(channel, HV_RING_SIZE * PAGE_SIZE,
256 HV_RING_SIZE * PAGE_SIZE);
257 if (ret)
258 goto fail;
259
260 set_channel_read_mode(channel, HV_CALL_ISR);
261
262 /* Fill general uio info */
263 pdata->info.name = "uio_hv_generic";
264 pdata->info.version = DRIVER_VERSION;
265 pdata->info.irqcontrol = hv_uio_irqcontrol;
266 pdata->info.open = hv_uio_open;
267 pdata->info.release = hv_uio_release;
268 pdata->info.irq = UIO_IRQ_CUSTOM;
269 atomic_set(&pdata->refcnt, 0);
270
271 /* mem resources */
272 pdata->info.mem[TXRX_RING_MAP].name = "txrx_rings";
273 ring_buffer = page_address(channel->ringbuffer_page);
274 pdata->info.mem[TXRX_RING_MAP].addr
275 = (uintptr_t)virt_to_phys(ring_buffer);
276 pdata->info.mem[TXRX_RING_MAP].size
277 = channel->ringbuffer_pagecount << PAGE_SHIFT;
278 pdata->info.mem[TXRX_RING_MAP].memtype = UIO_MEM_IOVA;
279
280 pdata->info.mem[INT_PAGE_MAP].name = "int_page";
281 pdata->info.mem[INT_PAGE_MAP].addr
282 = (uintptr_t)vmbus_connection.int_page;
283 pdata->info.mem[INT_PAGE_MAP].size = PAGE_SIZE;
284 pdata->info.mem[INT_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
285
286 pdata->info.mem[MON_PAGE_MAP].name = "monitor_page";
287 pdata->info.mem[MON_PAGE_MAP].addr
288 = (uintptr_t)vmbus_connection.monitor_pages[1];
289 pdata->info.mem[MON_PAGE_MAP].size = PAGE_SIZE;
290 pdata->info.mem[MON_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
291
292 pdata->recv_buf = vzalloc(RECV_BUFFER_SIZE);
293 if (pdata->recv_buf == NULL) {
294 ret = -ENOMEM;
295 goto fail_close;
296 }
297
298 ret = vmbus_establish_gpadl(channel, pdata->recv_buf,
299 RECV_BUFFER_SIZE, &pdata->recv_gpadl);
300 if (ret) {
301 vfree(pdata->recv_buf);
302 goto fail_close;
303 }
304
305 /* put Global Physical Address Label in name */
306 snprintf(pdata->recv_name, sizeof(pdata->recv_name),
307 "recv:%u", pdata->recv_gpadl);
308 pdata->info.mem[RECV_BUF_MAP].name = pdata->recv_name;
309 pdata->info.mem[RECV_BUF_MAP].addr
310 = (uintptr_t)pdata->recv_buf;
311 pdata->info.mem[RECV_BUF_MAP].size = RECV_BUFFER_SIZE;
312 pdata->info.mem[RECV_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
313
314 pdata->send_buf = vzalloc(SEND_BUFFER_SIZE);
315 if (pdata->send_buf == NULL) {
316 ret = -ENOMEM;
317 goto fail_close;
318 }
319
320 ret = vmbus_establish_gpadl(channel, pdata->send_buf,
321 SEND_BUFFER_SIZE, &pdata->send_gpadl);
322 if (ret) {
323 vfree(pdata->send_buf);
324 goto fail_close;
325 }
326
327 snprintf(pdata->send_name, sizeof(pdata->send_name),
328 "send:%u", pdata->send_gpadl);
329 pdata->info.mem[SEND_BUF_MAP].name = pdata->send_name;
330 pdata->info.mem[SEND_BUF_MAP].addr
331 = (uintptr_t)pdata->send_buf;
332 pdata->info.mem[SEND_BUF_MAP].size = SEND_BUFFER_SIZE;
333 pdata->info.mem[SEND_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
334
335 pdata->info.priv = pdata;
336 pdata->device = dev;
337
338 ret = uio_register_device(&dev->device, &pdata->info);
339 if (ret) {
340 dev_err(&dev->device, "hv_uio register failed\n");
341 goto fail_close;
342 }
343
344 ret = sysfs_create_bin_file(&channel->kobj, &ring_buffer_bin_attr);
345 if (ret)
346 dev_notice(&dev->device,
347 "sysfs create ring bin file failed; %d\n", ret);
348
349 hv_set_drvdata(dev, pdata);
350
351 return 0;
352
353 fail_close:
354 hv_uio_cleanup(dev, pdata);
355 fail:
356 kfree(pdata);
357
358 return ret;
359 }
360
361 static int
hv_uio_remove(struct hv_device *dev)362 hv_uio_remove(struct hv_device *dev)
363 {
364 struct hv_uio_private_data *pdata = hv_get_drvdata(dev);
365
366 if (!pdata)
367 return 0;
368
369 sysfs_remove_bin_file(&dev->channel->kobj, &ring_buffer_bin_attr);
370 uio_unregister_device(&pdata->info);
371 hv_uio_cleanup(dev, pdata);
372 hv_set_drvdata(dev, NULL);
373
374 vmbus_free_ring(dev->channel);
375 kfree(pdata);
376 return 0;
377 }
378
379 static struct hv_driver hv_uio_drv = {
380 .name = "uio_hv_generic",
381 .id_table = NULL, /* only dynamic id's */
382 .probe = hv_uio_probe,
383 .remove = hv_uio_remove,
384 };
385
386 static int __init
hyperv_module_init(void)387 hyperv_module_init(void)
388 {
389 return vmbus_driver_register(&hv_uio_drv);
390 }
391
392 static void __exit
hyperv_module_exit(void)393 hyperv_module_exit(void)
394 {
395 vmbus_driver_unregister(&hv_uio_drv);
396 }
397
398 module_init(hyperv_module_init);
399 module_exit(hyperv_module_exit);
400
401 MODULE_VERSION(DRIVER_VERSION);
402 MODULE_LICENSE("GPL v2");
403 MODULE_AUTHOR(DRIVER_AUTHOR);
404 MODULE_DESCRIPTION(DRIVER_DESC);
405