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 struct vmbus_gpadl recv_gpadl;
62 char recv_name[32]; /* "recv_4294967295" */
63
64 void *send_buf;
65 struct vmbus_gpadl 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 * With rescind callback registered, rescind path will not unregister the device
125 * from vmbus when the primary channel is rescinded.
126 * Without it, rescind handling is incomplete and next onoffer msg does not come.
127 * Unregister the device from vmbus here.
128 */
129 vmbus_device_unregister(channel->device_obj);
130 }
131
132 /* Sysfs API to allow mmap of the ring buffers
133 * The ring buffer is allocated as contiguous memory by vmbus_open
134 */
hv_uio_ring_mmap(struct file * filp,struct kobject * kobj,struct bin_attribute * attr,struct vm_area_struct * vma)135 static int hv_uio_ring_mmap(struct file *filp, struct kobject *kobj,
136 struct bin_attribute *attr,
137 struct vm_area_struct *vma)
138 {
139 struct vmbus_channel *channel
140 = container_of(kobj, struct vmbus_channel, kobj);
141 void *ring_buffer = page_address(channel->ringbuffer_page);
142
143 if (channel->state != CHANNEL_OPENED_STATE)
144 return -ENODEV;
145
146 return vm_iomap_memory(vma, virt_to_phys(ring_buffer),
147 channel->ringbuffer_pagecount << PAGE_SHIFT);
148 }
149
150 static const struct bin_attribute ring_buffer_bin_attr = {
151 .attr = {
152 .name = "ring",
153 .mode = 0600,
154 },
155 .size = 2 * HV_RING_SIZE * PAGE_SIZE,
156 .mmap = hv_uio_ring_mmap,
157 };
158
159 /* Callback from VMBUS subsystem when new channel created. */
160 static void
hv_uio_new_channel(struct vmbus_channel * new_sc)161 hv_uio_new_channel(struct vmbus_channel *new_sc)
162 {
163 struct hv_device *hv_dev = new_sc->primary_channel->device_obj;
164 struct device *device = &hv_dev->device;
165 const size_t ring_bytes = HV_RING_SIZE * PAGE_SIZE;
166 int ret;
167
168 /* Create host communication ring */
169 ret = vmbus_open(new_sc, ring_bytes, ring_bytes, NULL, 0,
170 hv_uio_channel_cb, new_sc);
171 if (ret) {
172 dev_err(device, "vmbus_open subchannel failed: %d\n", ret);
173 return;
174 }
175
176 /* Disable interrupts on sub channel */
177 new_sc->inbound.ring_buffer->interrupt_mask = 1;
178 set_channel_read_mode(new_sc, HV_CALL_ISR);
179
180 ret = sysfs_create_bin_file(&new_sc->kobj, &ring_buffer_bin_attr);
181 if (ret) {
182 dev_err(device, "sysfs create ring bin file failed; %d\n", ret);
183 vmbus_close(new_sc);
184 }
185 }
186
187 /* free the reserved buffers for send and receive */
188 static void
hv_uio_cleanup(struct hv_device * dev,struct hv_uio_private_data * pdata)189 hv_uio_cleanup(struct hv_device *dev, struct hv_uio_private_data *pdata)
190 {
191 if (pdata->send_gpadl.gpadl_handle) {
192 vmbus_teardown_gpadl(dev->channel, &pdata->send_gpadl);
193 if (!pdata->send_gpadl.decrypted)
194 vfree(pdata->send_buf);
195 }
196
197 if (pdata->recv_gpadl.gpadl_handle) {
198 vmbus_teardown_gpadl(dev->channel, &pdata->recv_gpadl);
199 if (!pdata->recv_gpadl.decrypted)
200 vfree(pdata->recv_buf);
201 }
202 }
203
204 /* VMBus primary channel is opened on first use */
205 static int
hv_uio_open(struct uio_info * info,struct inode * inode)206 hv_uio_open(struct uio_info *info, struct inode *inode)
207 {
208 struct hv_uio_private_data *pdata
209 = container_of(info, struct hv_uio_private_data, info);
210 struct hv_device *dev = pdata->device;
211 int ret;
212
213 if (atomic_inc_return(&pdata->refcnt) != 1)
214 return 0;
215
216 vmbus_set_chn_rescind_callback(dev->channel, hv_uio_rescind);
217 vmbus_set_sc_create_callback(dev->channel, hv_uio_new_channel);
218
219 ret = vmbus_connect_ring(dev->channel,
220 hv_uio_channel_cb, dev->channel);
221 if (ret == 0)
222 dev->channel->inbound.ring_buffer->interrupt_mask = 1;
223 else
224 atomic_dec(&pdata->refcnt);
225
226 return ret;
227 }
228
229 /* VMBus primary channel is closed on last close */
230 static int
hv_uio_release(struct uio_info * info,struct inode * inode)231 hv_uio_release(struct uio_info *info, struct inode *inode)
232 {
233 struct hv_uio_private_data *pdata
234 = container_of(info, struct hv_uio_private_data, info);
235 struct hv_device *dev = pdata->device;
236 int ret = 0;
237
238 if (atomic_dec_and_test(&pdata->refcnt))
239 ret = vmbus_disconnect_ring(dev->channel);
240
241 return ret;
242 }
243
244 static int
hv_uio_probe(struct hv_device * dev,const struct hv_vmbus_device_id * dev_id)245 hv_uio_probe(struct hv_device *dev,
246 const struct hv_vmbus_device_id *dev_id)
247 {
248 struct vmbus_channel *channel = dev->channel;
249 struct hv_uio_private_data *pdata;
250 void *ring_buffer;
251 int ret;
252
253 /* Communicating with host has to be via shared memory not hypercall */
254 if (!channel->offermsg.monitor_allocated) {
255 dev_err(&dev->device, "vmbus channel requires hypercall\n");
256 return -ENOTSUPP;
257 }
258
259 pdata = devm_kzalloc(&dev->device, sizeof(*pdata), GFP_KERNEL);
260 if (!pdata)
261 return -ENOMEM;
262
263 ret = vmbus_alloc_ring(channel, HV_RING_SIZE * PAGE_SIZE,
264 HV_RING_SIZE * PAGE_SIZE);
265 if (ret)
266 return ret;
267
268 set_channel_read_mode(channel, HV_CALL_ISR);
269
270 /* Fill general uio info */
271 pdata->info.name = "uio_hv_generic";
272 pdata->info.version = DRIVER_VERSION;
273 pdata->info.irqcontrol = hv_uio_irqcontrol;
274 pdata->info.open = hv_uio_open;
275 pdata->info.release = hv_uio_release;
276 pdata->info.irq = UIO_IRQ_CUSTOM;
277 atomic_set(&pdata->refcnt, 0);
278
279 /* mem resources */
280 pdata->info.mem[TXRX_RING_MAP].name = "txrx_rings";
281 ring_buffer = page_address(channel->ringbuffer_page);
282 pdata->info.mem[TXRX_RING_MAP].addr
283 = (uintptr_t)virt_to_phys(ring_buffer);
284 pdata->info.mem[TXRX_RING_MAP].size
285 = channel->ringbuffer_pagecount << PAGE_SHIFT;
286 pdata->info.mem[TXRX_RING_MAP].memtype = UIO_MEM_IOVA;
287
288 pdata->info.mem[INT_PAGE_MAP].name = "int_page";
289 pdata->info.mem[INT_PAGE_MAP].addr
290 = (uintptr_t)vmbus_connection.int_page;
291 pdata->info.mem[INT_PAGE_MAP].size = PAGE_SIZE;
292 pdata->info.mem[INT_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
293
294 pdata->info.mem[MON_PAGE_MAP].name = "monitor_page";
295 pdata->info.mem[MON_PAGE_MAP].addr
296 = (uintptr_t)vmbus_connection.monitor_pages[1];
297 pdata->info.mem[MON_PAGE_MAP].size = PAGE_SIZE;
298 pdata->info.mem[MON_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
299
300 pdata->recv_buf = vzalloc(RECV_BUFFER_SIZE);
301 if (pdata->recv_buf == NULL) {
302 ret = -ENOMEM;
303 goto fail_free_ring;
304 }
305
306 ret = vmbus_establish_gpadl(channel, pdata->recv_buf,
307 RECV_BUFFER_SIZE, &pdata->recv_gpadl);
308 if (ret) {
309 if (!pdata->recv_gpadl.decrypted)
310 vfree(pdata->recv_buf);
311 goto fail_close;
312 }
313
314 /* put Global Physical Address Label in name */
315 snprintf(pdata->recv_name, sizeof(pdata->recv_name),
316 "recv:%u", pdata->recv_gpadl.gpadl_handle);
317 pdata->info.mem[RECV_BUF_MAP].name = pdata->recv_name;
318 pdata->info.mem[RECV_BUF_MAP].addr
319 = (uintptr_t)pdata->recv_buf;
320 pdata->info.mem[RECV_BUF_MAP].size = RECV_BUFFER_SIZE;
321 pdata->info.mem[RECV_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
322
323 pdata->send_buf = vzalloc(SEND_BUFFER_SIZE);
324 if (pdata->send_buf == NULL) {
325 ret = -ENOMEM;
326 goto fail_close;
327 }
328
329 ret = vmbus_establish_gpadl(channel, pdata->send_buf,
330 SEND_BUFFER_SIZE, &pdata->send_gpadl);
331 if (ret) {
332 if (!pdata->send_gpadl.decrypted)
333 vfree(pdata->send_buf);
334 goto fail_close;
335 }
336
337 snprintf(pdata->send_name, sizeof(pdata->send_name),
338 "send:%u", pdata->send_gpadl.gpadl_handle);
339 pdata->info.mem[SEND_BUF_MAP].name = pdata->send_name;
340 pdata->info.mem[SEND_BUF_MAP].addr
341 = (uintptr_t)pdata->send_buf;
342 pdata->info.mem[SEND_BUF_MAP].size = SEND_BUFFER_SIZE;
343 pdata->info.mem[SEND_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
344
345 pdata->info.priv = pdata;
346 pdata->device = dev;
347
348 ret = uio_register_device(&dev->device, &pdata->info);
349 if (ret) {
350 dev_err(&dev->device, "hv_uio register failed\n");
351 goto fail_close;
352 }
353
354 ret = sysfs_create_bin_file(&channel->kobj, &ring_buffer_bin_attr);
355 if (ret)
356 dev_notice(&dev->device,
357 "sysfs create ring bin file failed; %d\n", ret);
358
359 hv_set_drvdata(dev, pdata);
360
361 return 0;
362
363 fail_close:
364 hv_uio_cleanup(dev, pdata);
365 fail_free_ring:
366 vmbus_free_ring(dev->channel);
367
368 return ret;
369 }
370
371 static void
hv_uio_remove(struct hv_device * dev)372 hv_uio_remove(struct hv_device *dev)
373 {
374 struct hv_uio_private_data *pdata = hv_get_drvdata(dev);
375
376 if (!pdata)
377 return;
378
379 sysfs_remove_bin_file(&dev->channel->kobj, &ring_buffer_bin_attr);
380 uio_unregister_device(&pdata->info);
381 hv_uio_cleanup(dev, pdata);
382
383 vmbus_free_ring(dev->channel);
384 }
385
386 static struct hv_driver hv_uio_drv = {
387 .name = "uio_hv_generic",
388 .id_table = NULL, /* only dynamic id's */
389 .probe = hv_uio_probe,
390 .remove = hv_uio_remove,
391 };
392
393 static int __init
hyperv_module_init(void)394 hyperv_module_init(void)
395 {
396 return vmbus_driver_register(&hv_uio_drv);
397 }
398
399 static void __exit
hyperv_module_exit(void)400 hyperv_module_exit(void)
401 {
402 vmbus_driver_unregister(&hv_uio_drv);
403 }
404
405 module_init(hyperv_module_init);
406 module_exit(hyperv_module_exit);
407
408 MODULE_VERSION(DRIVER_VERSION);
409 MODULE_LICENSE("GPL v2");
410 MODULE_AUTHOR(DRIVER_AUTHOR);
411 MODULE_DESCRIPTION(DRIVER_DESC);
412