uio_hv_generic.c

  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 SEND_BUFFER_SIZE (16 * 1024 * 1024)
 40#define RECV_BUFFER_SIZE (31 * 1024 * 1024)
 41
 42/*
 43 * List of resources to be mapped to user space
 44 * can be extended up to MAX_UIO_MAPS(5) items
 45 */
 46enum hv_uio_map {
 47	TXRX_RING_MAP = 0,
 48	INT_PAGE_MAP,
 49	MON_PAGE_MAP,
 50	RECV_BUF_MAP,
 51	SEND_BUF_MAP
 52};
 53
 54struct hv_uio_private_data {
 55	struct uio_info info;
 56	struct hv_device *device;
 57	atomic_t refcnt;
 58
 59	void	*recv_buf;
 60	struct vmbus_gpadl recv_gpadl;
 61	char	recv_name[32];	/* "recv_4294967295" */
 62
 63	void	*send_buf;
 64	struct vmbus_gpadl send_gpadl;
 65	char	send_name[32];
 66};
 67
 68static void set_event(struct vmbus_channel *channel, s32 irq_state)
 69{
 70	channel->inbound.ring_buffer->interrupt_mask = !irq_state;
 71	if (!channel->offermsg.monitor_allocated && irq_state) {
 72		/* MB is needed for host to see the interrupt mask first */
 73		virt_mb();
 74		vmbus_set_event(channel);
 75	}
 76}
 77
 78/*
 79 * This is the irqcontrol callback to be registered to uio_info.
 80 * It can be used to disable/enable interrupt from user space processes.
 81 *
 82 * @param info
 83 *  pointer to uio_info.
 84 * @param irq_state
 85 *  state value. 1 to enable interrupt, 0 to disable interrupt.
 86 */
 87static int
 88hv_uio_irqcontrol(struct uio_info *info, s32 irq_state)
 89{
 90	struct hv_uio_private_data *pdata = info->priv;
 91	struct hv_device *dev = pdata->device;
 92	struct vmbus_channel *primary, *sc;
 93
 94	primary = dev->channel;
 95	set_event(primary, irq_state);
 96
 97	mutex_lock(&vmbus_connection.channel_mutex);
 98	list_for_each_entry(sc, &primary->sc_list, sc_list)
 99		set_event(sc, irq_state);
100	mutex_unlock(&vmbus_connection.channel_mutex);
101
102	return 0;
103}
104
105/*
106 * Callback from vmbus_event when something is in inbound ring.
107 */
108static void hv_uio_channel_cb(void *context)
109{
110	struct vmbus_channel *chan = context;
111	struct hv_device *hv_dev;
112	struct hv_uio_private_data *pdata;
113
114	virt_mb();
115
116	/*
117	 * The callback may come from a subchannel, in which case look
118	 * for the hv device in the primary channel
119	 */
120	hv_dev = chan->primary_channel ?
121		 chan->primary_channel->device_obj : chan->device_obj;
122	pdata = hv_get_drvdata(hv_dev);
123	uio_event_notify(&pdata->info);
124}
125
126/*
127 * Callback from vmbus_event when channel is rescinded.
128 * It is meant for rescind of primary channels only.
129 */
130static void hv_uio_rescind(struct vmbus_channel *channel)
131{
132	struct hv_device *hv_dev = channel->device_obj;
133	struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev);
134
135	/*
136	 * Turn off the interrupt file handle
137	 * Next read for event will return -EIO
138	 */
139	pdata->info.irq = 0;
140
141	/* Wake up reader */
142	uio_event_notify(&pdata->info);
143
144	/*
145	 * With rescind callback registered, rescind path will not unregister the device
146	 * from vmbus when the primary channel is rescinded.
147	 * Without it, rescind handling is incomplete and next onoffer msg does not come.
148	 * Unregister the device from vmbus here.
149	 */
150	vmbus_device_unregister(channel->device_obj);
151}
152
153/* Function used for mmap of ring buffer sysfs interface.
154 * The ring buffer is allocated as contiguous memory by vmbus_open
155 */
156static int
157hv_uio_ring_mmap(struct vmbus_channel *channel, struct vm_area_struct *vma)
158{
159	void *ring_buffer = page_address(channel->ringbuffer_page);
160
161	if (channel->state != CHANNEL_OPENED_STATE)
162		return -ENODEV;
163
164	return vm_iomap_memory(vma, virt_to_phys(ring_buffer),
165			       channel->ringbuffer_pagecount << PAGE_SHIFT);
166}
167
168/* Callback from VMBUS subsystem when new channel created. */
169static void
170hv_uio_new_channel(struct vmbus_channel *new_sc)
171{
172	struct hv_device *hv_dev = new_sc->primary_channel->device_obj;
173	struct device *device = &hv_dev->device;
174	const size_t ring_bytes = SZ_2M;
175	int ret;
176
177	/* Create host communication ring */
178	ret = vmbus_open(new_sc, ring_bytes, ring_bytes, NULL, 0,
179			 hv_uio_channel_cb, new_sc);
180	if (ret) {
181		dev_err(device, "vmbus_open subchannel failed: %d\n", ret);
182		return;
183	}
184
185	set_channel_read_mode(new_sc, HV_CALL_ISR);
186	ret = hv_create_ring_sysfs(new_sc, hv_uio_ring_mmap);
187	if (ret) {
188		dev_err(device, "sysfs create ring bin file failed; %d\n", ret);
189		vmbus_close(new_sc);
190	}
191}
192
193/* free the reserved buffers for send and receive */
194static void
195hv_uio_cleanup(struct hv_device *dev, struct hv_uio_private_data *pdata)
196{
197	if (pdata->send_gpadl.gpadl_handle) {
198		vmbus_teardown_gpadl(dev->channel, &pdata->send_gpadl);
199		if (!pdata->send_gpadl.decrypted)
200			vfree(pdata->send_buf);
201	}
202
203	if (pdata->recv_gpadl.gpadl_handle) {
204		vmbus_teardown_gpadl(dev->channel, &pdata->recv_gpadl);
205		if (!pdata->recv_gpadl.decrypted)
206			vfree(pdata->recv_buf);
207	}
208}
209
210/* VMBus primary channel is opened on first use */
211static int
212hv_uio_open(struct uio_info *info, struct inode *inode)
213{
214	struct hv_uio_private_data *pdata
215		= container_of(info, struct hv_uio_private_data, info);
216	struct hv_device *dev = pdata->device;
217	int ret;
218
219	if (atomic_inc_return(&pdata->refcnt) != 1)
220		return 0;
221
222	vmbus_set_chn_rescind_callback(dev->channel, hv_uio_rescind);
223	vmbus_set_sc_create_callback(dev->channel, hv_uio_new_channel);
224
225	ret = vmbus_connect_ring(dev->channel,
226				 hv_uio_channel_cb, dev->channel);
227	if (ret)
228		atomic_dec(&pdata->refcnt);
229
230	return ret;
231}
232
233/* VMBus primary channel is closed on last close */
234static int
235hv_uio_release(struct uio_info *info, struct inode *inode)
236{
237	struct hv_uio_private_data *pdata
238		= container_of(info, struct hv_uio_private_data, info);
239	struct hv_device *dev = pdata->device;
240	int ret = 0;
241
242	if (atomic_dec_and_test(&pdata->refcnt))
243		ret = vmbus_disconnect_ring(dev->channel);
244
245	return ret;
246}
247
248static int
249hv_uio_probe(struct hv_device *dev,
250	     const struct hv_vmbus_device_id *dev_id)
251{
252	struct vmbus_channel *channel = dev->channel;
253	struct hv_uio_private_data *pdata;
254	void *ring_buffer;
255	int ret;
256	size_t ring_size = hv_dev_ring_size(channel);
257
258	if (!ring_size)
259		ring_size = SZ_2M;
260
261	/* Adjust ring size if necessary to have it page aligned */
262	ring_size = VMBUS_RING_SIZE(ring_size);
263
264	pdata = devm_kzalloc(&dev->device, sizeof(*pdata), GFP_KERNEL);
265	if (!pdata)
266		return -ENOMEM;
267
268	ret = vmbus_alloc_ring(channel, ring_size, ring_size);
269	if (ret)
270		return ret;
271
272	set_channel_read_mode(channel, HV_CALL_ISR);
273
274	/* Fill general uio info */
275	pdata->info.name = "uio_hv_generic";
276	pdata->info.version = DRIVER_VERSION;
277	pdata->info.irqcontrol = hv_uio_irqcontrol;
278	pdata->info.open = hv_uio_open;
279	pdata->info.release = hv_uio_release;
280	pdata->info.irq = UIO_IRQ_CUSTOM;
281	atomic_set(&pdata->refcnt, 0);
282
283	/* mem resources */
284	pdata->info.mem[TXRX_RING_MAP].name = "txrx_rings";
285	ring_buffer = page_address(channel->ringbuffer_page);
286	pdata->info.mem[TXRX_RING_MAP].addr
287		= (uintptr_t)virt_to_phys(ring_buffer);
288	pdata->info.mem[TXRX_RING_MAP].size
289		= channel->ringbuffer_pagecount << PAGE_SHIFT;
290	pdata->info.mem[TXRX_RING_MAP].memtype = UIO_MEM_IOVA;
291
292	pdata->info.mem[INT_PAGE_MAP].name = "int_page";
293	pdata->info.mem[INT_PAGE_MAP].addr
294		= (uintptr_t)vmbus_connection.int_page;
295	pdata->info.mem[INT_PAGE_MAP].size = HV_HYP_PAGE_SIZE;
296	pdata->info.mem[INT_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
297
298	pdata->info.mem[MON_PAGE_MAP].name = "monitor_page";
299	pdata->info.mem[MON_PAGE_MAP].addr
300		= (uintptr_t)vmbus_connection.monitor_pages[1];
301	pdata->info.mem[MON_PAGE_MAP].size = HV_HYP_PAGE_SIZE;
302	pdata->info.mem[MON_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
303
304	if (channel->device_id == HV_NIC) {
305		pdata->recv_buf = vzalloc(RECV_BUFFER_SIZE);
306		if (!pdata->recv_buf) {
307			ret = -ENOMEM;
308			goto fail_free_ring;
309		}
310
311		ret = vmbus_establish_gpadl(channel, pdata->recv_buf,
312					    RECV_BUFFER_SIZE, &pdata->recv_gpadl);
313		if (ret) {
314			if (!pdata->recv_gpadl.decrypted)
315				vfree(pdata->recv_buf);
316			goto fail_close;
317		}
318
319		/* put Global Physical Address Label in name */
320		snprintf(pdata->recv_name, sizeof(pdata->recv_name),
321			 "recv:%u", pdata->recv_gpadl.gpadl_handle);
322		pdata->info.mem[RECV_BUF_MAP].name = pdata->recv_name;
323		pdata->info.mem[RECV_BUF_MAP].addr = (uintptr_t)pdata->recv_buf;
324		pdata->info.mem[RECV_BUF_MAP].size = RECV_BUFFER_SIZE;
325		pdata->info.mem[RECV_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
326
327		pdata->send_buf = vzalloc(SEND_BUFFER_SIZE);
328		if (!pdata->send_buf) {
329			ret = -ENOMEM;
330			goto fail_close;
331		}
332
333		ret = vmbus_establish_gpadl(channel, pdata->send_buf,
334					    SEND_BUFFER_SIZE, &pdata->send_gpadl);
335		if (ret) {
336			if (!pdata->send_gpadl.decrypted)
337				vfree(pdata->send_buf);
338			goto fail_close;
339		}
340
341		snprintf(pdata->send_name, sizeof(pdata->send_name),
342			 "send:%u", pdata->send_gpadl.gpadl_handle);
343		pdata->info.mem[SEND_BUF_MAP].name = pdata->send_name;
344		pdata->info.mem[SEND_BUF_MAP].addr = (uintptr_t)pdata->send_buf;
345		pdata->info.mem[SEND_BUF_MAP].size = SEND_BUFFER_SIZE;
346		pdata->info.mem[SEND_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
347	}
348
349	pdata->info.priv = pdata;
350	pdata->device = dev;
351
352	ret = uio_register_device(&dev->device, &pdata->info);
353	if (ret) {
354		dev_err(&dev->device, "hv_uio register failed\n");
355		goto fail_close;
356	}
357
358	/*
359	 * This internally calls sysfs_update_group, which returns a non-zero value if it executes
360	 * before sysfs_create_group. This is expected as the 'ring' will be created later in
361	 * vmbus_device_register() -> vmbus_add_channel_kobj(). Thus, no need to check the return
362	 * value and print warning.
363	 *
364	 * Creating/exposing sysfs in driver probe is not encouraged as it can lead to race
365	 * conditions with userspace. For backward compatibility, "ring" sysfs could not be removed
366	 * or decoupled from uio_hv_generic probe. Userspace programs can make use of inotify
367	 * APIs to make sure that ring is created.
368	 */
369	hv_create_ring_sysfs(channel, hv_uio_ring_mmap);
370
371	hv_set_drvdata(dev, pdata);
372
373	return 0;
374
375fail_close:
376	hv_uio_cleanup(dev, pdata);
377fail_free_ring:
378	vmbus_free_ring(dev->channel);
379
380	return ret;
381}
382
383static void
384hv_uio_remove(struct hv_device *dev)
385{
386	struct hv_uio_private_data *pdata = hv_get_drvdata(dev);
387
388	if (!pdata)
389		return;
390
391	hv_remove_ring_sysfs(dev->channel);
392	uio_unregister_device(&pdata->info);
393	hv_uio_cleanup(dev, pdata);
394
395	vmbus_free_ring(dev->channel);
396}
397
398static struct hv_driver hv_uio_drv = {
399	.name = "uio_hv_generic",
400	.id_table = NULL, /* only dynamic id's */
401	.probe = hv_uio_probe,
402	.remove = hv_uio_remove,
403};
404
405static int __init
406hyperv_module_init(void)
407{
408	return vmbus_driver_register(&hv_uio_drv);
409}
410
411static void __exit
412hyperv_module_exit(void)
413{
414	vmbus_driver_unregister(&hv_uio_drv);
415}
416
417module_init(hyperv_module_init);
418module_exit(hyperv_module_exit);
419
420MODULE_VERSION(DRIVER_VERSION);
421MODULE_LICENSE("GPL v2");
422MODULE_AUTHOR(DRIVER_AUTHOR);
423MODULE_DESCRIPTION(DRIVER_DESC);