summaryrefslogtreecommitdiffstats
path: root/drivers/virt/acrn/ioeventfd.c
blob: ac4037e9f947ec95c4395de56764b30d3fa14ce0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
// SPDX-License-Identifier: GPL-2.0
/*
 * ACRN HSM eventfd - use eventfd objects to signal expected I/O requests
 *
 * Copyright (C) 2020 Intel Corporation. All rights reserved.
 *
 * Authors:
 *	Shuo Liu <shuo.a.liu@intel.com>
 *	Yakui Zhao <yakui.zhao@intel.com>
 */

#include <linux/eventfd.h>
#include <linux/slab.h>

#include "acrn_drv.h"

/**
 * struct hsm_ioeventfd - Properties of HSM ioeventfd
 * @list:	Entry within &acrn_vm.ioeventfds of ioeventfds of a VM
 * @eventfd:	Eventfd of the HSM ioeventfd
 * @addr:	Address of I/O range
 * @data:	Data for matching
 * @length:	Length of I/O range
 * @type:	Type of I/O range (ACRN_IOREQ_TYPE_MMIO/ACRN_IOREQ_TYPE_PORTIO)
 * @wildcard:	Data matching or not
 */
struct hsm_ioeventfd {
	struct list_head	list;
	struct eventfd_ctx	*eventfd;
	u64			addr;
	u64			data;
	int			length;
	int			type;
	bool			wildcard;
};

static inline int ioreq_type_from_flags(int flags)
{
	return flags & ACRN_IOEVENTFD_FLAG_PIO ?
		       ACRN_IOREQ_TYPE_PORTIO : ACRN_IOREQ_TYPE_MMIO;
}

static void acrn_ioeventfd_shutdown(struct acrn_vm *vm, struct hsm_ioeventfd *p)
{
	lockdep_assert_held(&vm->ioeventfds_lock);

	eventfd_ctx_put(p->eventfd);
	list_del(&p->list);
	kfree(p);
}

static bool hsm_ioeventfd_is_conflict(struct acrn_vm *vm,
				      struct hsm_ioeventfd *ioeventfd)
{
	struct hsm_ioeventfd *p;

	lockdep_assert_held(&vm->ioeventfds_lock);

	/* Either one is wildcard, the data matching will be skipped. */
	list_for_each_entry(p, &vm->ioeventfds, list)
		if (p->eventfd == ioeventfd->eventfd &&
		    p->addr == ioeventfd->addr &&
		    p->type == ioeventfd->type &&
		    (p->wildcard || ioeventfd->wildcard ||
			p->data == ioeventfd->data))
			return true;

	return false;
}

/*
 * Assign an eventfd to a VM and create a HSM ioeventfd associated with the
 * eventfd. The properties of the HSM ioeventfd are built from a &struct
 * acrn_ioeventfd.
 */
static int acrn_ioeventfd_assign(struct acrn_vm *vm,
				 struct acrn_ioeventfd *args)
{
	struct eventfd_ctx *eventfd;
	struct hsm_ioeventfd *p;
	int ret;

	/* Check for range overflow */
	if (args->addr + args->len < args->addr)
		return -EINVAL;

	/*
	 * Currently, acrn_ioeventfd is used to support vhost. 1,2,4,8 width
	 * accesses can cover vhost's requirements.
	 */
	if (!(args->len == 1 || args->len == 2 ||
	      args->len == 4 || args->len == 8))
		return -EINVAL;

	eventfd = eventfd_ctx_fdget(args->fd);
	if (IS_ERR(eventfd))
		return PTR_ERR(eventfd);

	p = kzalloc(sizeof(*p), GFP_KERNEL);
	if (!p) {
		ret = -ENOMEM;
		goto fail;
	}

	INIT_LIST_HEAD(&p->list);
	p->addr = args->addr;
	p->length = args->len;
	p->eventfd = eventfd;
	p->type = ioreq_type_from_flags(args->flags);

	/*
	 * ACRN_IOEVENTFD_FLAG_DATAMATCH flag is set in virtio 1.0 support, the
	 * writing of notification register of each virtqueue may trigger the
	 * notification. There is no data matching requirement.
	 */
	if (args->flags & ACRN_IOEVENTFD_FLAG_DATAMATCH)
		p->data = args->data;
	else
		p->wildcard = true;

	mutex_lock(&vm->ioeventfds_lock);

	if (hsm_ioeventfd_is_conflict(vm, p)) {
		ret = -EEXIST;
		goto unlock_fail;
	}

	/* register the I/O range into ioreq client */
	ret = acrn_ioreq_range_add(vm->ioeventfd_client, p->type,
				   p->addr, p->addr + p->length - 1);
	if (ret < 0)
		goto unlock_fail;

	list_add_tail(&p->list, &vm->ioeventfds);
	mutex_unlock(&vm->ioeventfds_lock);

	return 0;

unlock_fail:
	mutex_unlock(&vm->ioeventfds_lock);
	kfree(p);
fail:
	eventfd_ctx_put(eventfd);
	return ret;
}

static int acrn_ioeventfd_deassign(struct acrn_vm *vm,
				   struct acrn_ioeventfd *args)
{
	struct hsm_ioeventfd *p;
	struct eventfd_ctx *eventfd;

	eventfd = eventfd_ctx_fdget(args->fd);
	if (IS_ERR(eventfd))
		return PTR_ERR(eventfd);

	mutex_lock(&vm->ioeventfds_lock);
	list_for_each_entry(p, &vm->ioeventfds, list) {
		if (p->eventfd != eventfd)
			continue;

		acrn_ioreq_range_del(vm->ioeventfd_client, p->type,
				     p->addr, p->addr + p->length - 1);
		acrn_ioeventfd_shutdown(vm, p);
		break;
	}
	mutex_unlock(&vm->ioeventfds_lock);

	eventfd_ctx_put(eventfd);
	return 0;
}

static struct hsm_ioeventfd *hsm_ioeventfd_match(struct acrn_vm *vm, u64 addr,
						 u64 data, int len, int type)
{
	struct hsm_ioeventfd *p = NULL;

	lockdep_assert_held(&vm->ioeventfds_lock);

	list_for_each_entry(p, &vm->ioeventfds, list) {
		if (p->type == type && p->addr == addr && p->length >= len &&
		    (p->wildcard || p->data == data))
			return p;
	}

	return NULL;
}

static int acrn_ioeventfd_handler(struct acrn_ioreq_client *client,
				  struct acrn_io_request *req)
{
	struct hsm_ioeventfd *p;
	u64 addr, val;
	int size;

	if (req->type == ACRN_IOREQ_TYPE_MMIO) {
		/*
		 * I/O requests are dispatched by range check only, so a
		 * acrn_ioreq_client need process both READ and WRITE accesses
		 * of same range. READ accesses are safe to be ignored here
		 * because virtio PCI devices write the notify registers for
		 * notification.
		 */
		if (req->reqs.mmio_request.direction == ACRN_IOREQ_DIR_READ) {
			/* reading does nothing and return 0 */
			req->reqs.mmio_request.value = 0;
			return 0;
		}
		addr = req->reqs.mmio_request.address;
		size = req->reqs.mmio_request.size;
		val = req->reqs.mmio_request.value;
	} else {
		if (req->reqs.pio_request.direction == ACRN_IOREQ_DIR_READ) {
			/* reading does nothing and return 0 */
			req->reqs.pio_request.value = 0;
			return 0;
		}
		addr = req->reqs.pio_request.address;
		size = req->reqs.pio_request.size;
		val = req->reqs.pio_request.value;
	}

	mutex_lock(&client->vm->ioeventfds_lock);
	p = hsm_ioeventfd_match(client->vm, addr, val, size, req->type);
	if (p)
		eventfd_signal(p->eventfd, 1);
	mutex_unlock(&client->vm->ioeventfds_lock);

	return 0;
}

int acrn_ioeventfd_config(struct acrn_vm *vm, struct acrn_ioeventfd *args)
{
	int ret;

	if (args->flags & ACRN_IOEVENTFD_FLAG_DEASSIGN)
		ret = acrn_ioeventfd_deassign(vm, args);
	else
		ret = acrn_ioeventfd_assign(vm, args);

	return ret;
}

int acrn_ioeventfd_init(struct acrn_vm *vm)
{
	char name[ACRN_NAME_LEN];

	mutex_init(&vm->ioeventfds_lock);
	INIT_LIST_HEAD(&vm->ioeventfds);
	snprintf(name, sizeof(name), "ioeventfd-%u", vm->vmid);
	vm->ioeventfd_client = acrn_ioreq_client_create(vm,
							acrn_ioeventfd_handler,
							NULL, false, name);
	if (!vm->ioeventfd_client) {
		dev_err(acrn_dev.this_device, "Failed to create ioeventfd ioreq client!\n");
		return -EINVAL;
	}

	dev_dbg(acrn_dev.this_device, "VM %u ioeventfd init.\n", vm->vmid);
	return 0;
}

void acrn_ioeventfd_deinit(struct acrn_vm *vm)
{
	struct hsm_ioeventfd *p, *next;

	dev_dbg(acrn_dev.this_device, "VM %u ioeventfd deinit.\n", vm->vmid);
	acrn_ioreq_client_destroy(vm->ioeventfd_client);
	mutex_lock(&vm->ioeventfds_lock);
	list_for_each_entry_safe(p, next, &vm->ioeventfds, list)
		acrn_ioeventfd_shutdown(vm, p);
	mutex_unlock(&vm->ioeventfds_lock);
}