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 */
47enum 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
55struct 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 */
78static int
79hv_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 */
93static 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 */
108static void hv_uio_rescind(struct vmbus_channel *channel)
109{
110	struct hv_device *hv_dev = channel->primary_channel->device_obj;
111	struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev);
112
113	/*
114	 * Turn off the interrupt file handle
115	 * Next read for event will return -EIO
116	 */
117	pdata->info.irq = 0;
118
119	/* Wake up reader */
120	uio_event_notify(&pdata->info);
121}
122
123/* Sysfs API to allow mmap of the ring buffers
124 * The ring buffer is allocated as contiguous memory by vmbus_open
125 */
126static int hv_uio_ring_mmap(struct file *filp, struct kobject *kobj,
127			    struct bin_attribute *attr,
128			    struct vm_area_struct *vma)
129{
130	struct vmbus_channel *channel
131		= container_of(kobj, struct vmbus_channel, kobj);
132	void *ring_buffer = page_address(channel->ringbuffer_page);
133
134	if (channel->state != CHANNEL_OPENED_STATE)
135		return -ENODEV;
136
137	return vm_iomap_memory(vma, virt_to_phys(ring_buffer),
138			       channel->ringbuffer_pagecount << PAGE_SHIFT);
139}
140
141static const struct bin_attribute ring_buffer_bin_attr = {
142	.attr = {
143		.name = "ring",
144		.mode = 0600,
145	},
146	.size = 2 * HV_RING_SIZE * PAGE_SIZE,
147	.mmap = hv_uio_ring_mmap,
148};
149
150/* Callback from VMBUS subsystem when new channel created. */
151static void
152hv_uio_new_channel(struct vmbus_channel *new_sc)
153{
154	struct hv_device *hv_dev = new_sc->primary_channel->device_obj;
155	struct device *device = &hv_dev->device;
156	const size_t ring_bytes = HV_RING_SIZE * PAGE_SIZE;
157	int ret;
158
159	/* Create host communication ring */
160	ret = vmbus_open(new_sc, ring_bytes, ring_bytes, NULL, 0,
161			 hv_uio_channel_cb, new_sc);
162	if (ret) {
163		dev_err(device, "vmbus_open subchannel failed: %d\n", ret);
164		return;
165	}
166
167	/* Disable interrupts on sub channel */
168	new_sc->inbound.ring_buffer->interrupt_mask = 1;
169	set_channel_read_mode(new_sc, HV_CALL_ISR);
170
171	ret = sysfs_create_bin_file(&new_sc->kobj, &ring_buffer_bin_attr);
172	if (ret) {
173		dev_err(device, "sysfs create ring bin file failed; %d\n", ret);
174		vmbus_close(new_sc);
175	}
176}
177
178/* free the reserved buffers for send and receive */
179static void
180hv_uio_cleanup(struct hv_device *dev, struct hv_uio_private_data *pdata)
181{
182	if (pdata->send_gpadl.gpadl_handle) {
183		vmbus_teardown_gpadl(dev->channel, &pdata->send_gpadl);
184		if (!pdata->send_gpadl.decrypted)
185			vfree(pdata->send_buf);
186	}
187
188	if (pdata->recv_gpadl.gpadl_handle) {
189		vmbus_teardown_gpadl(dev->channel, &pdata->recv_gpadl);
190		if (!pdata->recv_gpadl.decrypted)
191			vfree(pdata->recv_buf);
192	}
193}
194
195/* VMBus primary channel is opened on first use */
196static int
197hv_uio_open(struct uio_info *info, struct inode *inode)
198{
199	struct hv_uio_private_data *pdata
200		= container_of(info, struct hv_uio_private_data, info);
201	struct hv_device *dev = pdata->device;
202	int ret;
203
204	if (atomic_inc_return(&pdata->refcnt) != 1)
205		return 0;
206
207	vmbus_set_chn_rescind_callback(dev->channel, hv_uio_rescind);
208	vmbus_set_sc_create_callback(dev->channel, hv_uio_new_channel);
209
210	ret = vmbus_connect_ring(dev->channel,
211				 hv_uio_channel_cb, dev->channel);
212	if (ret == 0)
213		dev->channel->inbound.ring_buffer->interrupt_mask = 1;
214	else
215		atomic_dec(&pdata->refcnt);
216
217	return ret;
218}
219
220/* VMBus primary channel is closed on last close */
221static int
222hv_uio_release(struct uio_info *info, struct inode *inode)
223{
224	struct hv_uio_private_data *pdata
225		= container_of(info, struct hv_uio_private_data, info);
226	struct hv_device *dev = pdata->device;
227	int ret = 0;
228
229	if (atomic_dec_and_test(&pdata->refcnt))
230		ret = vmbus_disconnect_ring(dev->channel);
231
232	return ret;
233}
234
235static int
236hv_uio_probe(struct hv_device *dev,
237	     const struct hv_vmbus_device_id *dev_id)
238{
239	struct vmbus_channel *channel = dev->channel;
240	struct hv_uio_private_data *pdata;
241	void *ring_buffer;
242	int ret;
243
244	/* Communicating with host has to be via shared memory not hypercall */
245	if (!channel->offermsg.monitor_allocated) {
246		dev_err(&dev->device, "vmbus channel requires hypercall\n");
247		return -ENOTSUPP;
248	}
249
250	pdata = devm_kzalloc(&dev->device, sizeof(*pdata), GFP_KERNEL);
251	if (!pdata)
252		return -ENOMEM;
253
254	ret = vmbus_alloc_ring(channel, HV_RING_SIZE * PAGE_SIZE,
255			       HV_RING_SIZE * PAGE_SIZE);
256	if (ret)
257		return ret;
258
259	set_channel_read_mode(channel, HV_CALL_ISR);
260
261	/* Fill general uio info */
262	pdata->info.name = "uio_hv_generic";
263	pdata->info.version = DRIVER_VERSION;
264	pdata->info.irqcontrol = hv_uio_irqcontrol;
265	pdata->info.open = hv_uio_open;
266	pdata->info.release = hv_uio_release;
267	pdata->info.irq = UIO_IRQ_CUSTOM;
268	atomic_set(&pdata->refcnt, 0);
269
270	/* mem resources */
271	pdata->info.mem[TXRX_RING_MAP].name = "txrx_rings";
272	ring_buffer = page_address(channel->ringbuffer_page);
273	pdata->info.mem[TXRX_RING_MAP].addr
274		= (uintptr_t)virt_to_phys(ring_buffer);
275	pdata->info.mem[TXRX_RING_MAP].size
276		= channel->ringbuffer_pagecount << PAGE_SHIFT;
277	pdata->info.mem[TXRX_RING_MAP].memtype = UIO_MEM_IOVA;
278
279	pdata->info.mem[INT_PAGE_MAP].name = "int_page";
280	pdata->info.mem[INT_PAGE_MAP].addr
281		= (uintptr_t)vmbus_connection.int_page;
282	pdata->info.mem[INT_PAGE_MAP].size = PAGE_SIZE;
283	pdata->info.mem[INT_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
284
285	pdata->info.mem[MON_PAGE_MAP].name = "monitor_page";
286	pdata->info.mem[MON_PAGE_MAP].addr
287		= (uintptr_t)vmbus_connection.monitor_pages[1];
288	pdata->info.mem[MON_PAGE_MAP].size = PAGE_SIZE;
289	pdata->info.mem[MON_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
290
291	pdata->recv_buf = vzalloc(RECV_BUFFER_SIZE);
292	if (pdata->recv_buf == NULL) {
293		ret = -ENOMEM;
294		goto fail_free_ring;
295	}
296
297	ret = vmbus_establish_gpadl(channel, pdata->recv_buf,
298				    RECV_BUFFER_SIZE, &pdata->recv_gpadl);
299	if (ret) {
300		if (!pdata->recv_gpadl.decrypted)
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.gpadl_handle);
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		if (!pdata->send_gpadl.decrypted)
324			vfree(pdata->send_buf);
325		goto fail_close;
326	}
327
328	snprintf(pdata->send_name, sizeof(pdata->send_name),
329		 "send:%u", pdata->send_gpadl.gpadl_handle);
330	pdata->info.mem[SEND_BUF_MAP].name = pdata->send_name;
331	pdata->info.mem[SEND_BUF_MAP].addr
332		= (uintptr_t)pdata->send_buf;
333	pdata->info.mem[SEND_BUF_MAP].size = SEND_BUFFER_SIZE;
334	pdata->info.mem[SEND_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
335
336	pdata->info.priv = pdata;
337	pdata->device = dev;
338
339	ret = uio_register_device(&dev->device, &pdata->info);
340	if (ret) {
341		dev_err(&dev->device, "hv_uio register failed\n");
342		goto fail_close;
343	}
344
345	ret = sysfs_create_bin_file(&channel->kobj, &ring_buffer_bin_attr);
346	if (ret)
347		dev_notice(&dev->device,
348			   "sysfs create ring bin file failed; %d\n", ret);
349
350	hv_set_drvdata(dev, pdata);
351
352	return 0;
353
354fail_close:
355	hv_uio_cleanup(dev, pdata);
356fail_free_ring:
357	vmbus_free_ring(dev->channel);
358
359	return ret;
360}
361
362static void
363hv_uio_remove(struct hv_device *dev)
364{
365	struct hv_uio_private_data *pdata = hv_get_drvdata(dev);
366
367	if (!pdata)
368		return;
369
370	sysfs_remove_bin_file(&dev->channel->kobj, &ring_buffer_bin_attr);
371	uio_unregister_device(&pdata->info);
372	hv_uio_cleanup(dev, pdata);
373
374	vmbus_free_ring(dev->channel);
375}
376
377static struct hv_driver hv_uio_drv = {
378	.name = "uio_hv_generic",
379	.id_table = NULL, /* only dynamic id's */
380	.probe = hv_uio_probe,
381	.remove = hv_uio_remove,
382};
383
384static int __init
385hyperv_module_init(void)
386{
387	return vmbus_driver_register(&hv_uio_drv);
388}
389
390static void __exit
391hyperv_module_exit(void)
392{
393	vmbus_driver_unregister(&hv_uio_drv);
394}
395
396module_init(hyperv_module_init);
397module_exit(hyperv_module_exit);
398
399MODULE_VERSION(DRIVER_VERSION);
400MODULE_LICENSE("GPL v2");
401MODULE_AUTHOR(DRIVER_AUTHOR);
402MODULE_DESCRIPTION(DRIVER_DESC);
403