1// SPDX-License-Identifier: GPL-2.0-or-later
2 /* Management for virtio crypto devices (refer to adf_dev_mgr.c)
3  *
4  * Copyright 2016 HUAWEI TECHNOLOGIES CO., LTD.
5  */
6
7#include <linux/mutex.h>
8#include <linux/list.h>
9#include <linux/module.h>
10
11#include <uapi/linux/virtio_crypto.h>
12#include "virtio_crypto_common.h"
13
14static LIST_HEAD(virtio_crypto_table);
15static uint32_t num_devices;
16
17/* The table_lock protects the above global list and num_devices */
18static DEFINE_MUTEX(table_lock);
19
20#define VIRTIO_CRYPTO_MAX_DEVICES 32
21
22
23/*
24 * virtcrypto_devmgr_add_dev() - Add vcrypto_dev to the acceleration
25 * framework.
26 * @vcrypto_dev:  Pointer to virtio crypto device.
27 *
28 * Function adds virtio crypto device to the global list.
29 * To be used by virtio crypto device specific drivers.
30 *
31 * Return: 0 on success, error code othewise.
32 */
33int virtcrypto_devmgr_add_dev(struct virtio_crypto *vcrypto_dev)
34{
35	struct list_head *itr;
36
37	mutex_lock(&table_lock);
38	if (num_devices == VIRTIO_CRYPTO_MAX_DEVICES) {
39		pr_info("virtio_crypto: only support up to %d devices\n",
40			    VIRTIO_CRYPTO_MAX_DEVICES);
41		mutex_unlock(&table_lock);
42		return -EFAULT;
43	}
44
45	list_for_each(itr, &virtio_crypto_table) {
46		struct virtio_crypto *ptr =
47				list_entry(itr, struct virtio_crypto, list);
48
49		if (ptr == vcrypto_dev) {
50			mutex_unlock(&table_lock);
51			return -EEXIST;
52		}
53	}
54	atomic_set(&vcrypto_dev->ref_count, 0);
55	list_add_tail(&vcrypto_dev->list, &virtio_crypto_table);
56	vcrypto_dev->dev_id = num_devices++;
57	mutex_unlock(&table_lock);
58	return 0;
59}
60
61struct list_head *virtcrypto_devmgr_get_head(void)
62{
63	return &virtio_crypto_table;
64}
65
66/*
67 * virtcrypto_devmgr_rm_dev() - Remove vcrypto_dev from the acceleration
68 * framework.
69 * @vcrypto_dev:  Pointer to virtio crypto device.
70 *
71 * Function removes virtio crypto device from the acceleration framework.
72 * To be used by virtio crypto device specific drivers.
73 *
74 * Return: void
75 */
76void virtcrypto_devmgr_rm_dev(struct virtio_crypto *vcrypto_dev)
77{
78	mutex_lock(&table_lock);
79	list_del(&vcrypto_dev->list);
80	num_devices--;
81	mutex_unlock(&table_lock);
82}
83
84/*
85 * virtcrypto_devmgr_get_first()
86 *
87 * Function returns the first virtio crypto device from the acceleration
88 * framework.
89 *
90 * To be used by virtio crypto device specific drivers.
91 *
92 * Return: pointer to vcrypto_dev or NULL if not found.
93 */
94struct virtio_crypto *virtcrypto_devmgr_get_first(void)
95{
96	struct virtio_crypto *dev = NULL;
97
98	mutex_lock(&table_lock);
99	if (!list_empty(&virtio_crypto_table))
100		dev = list_first_entry(&virtio_crypto_table,
101					struct virtio_crypto,
102				    list);
103	mutex_unlock(&table_lock);
104	return dev;
105}
106
107/*
108 * virtcrypto_dev_in_use() - Check whether vcrypto_dev is currently in use
109 * @vcrypto_dev: Pointer to virtio crypto device.
110 *
111 * To be used by virtio crypto device specific drivers.
112 *
113 * Return: 1 when device is in use, 0 otherwise.
114 */
115int virtcrypto_dev_in_use(struct virtio_crypto *vcrypto_dev)
116{
117	return atomic_read(&vcrypto_dev->ref_count) != 0;
118}
119
120/*
121 * virtcrypto_dev_get() - Increment vcrypto_dev reference count
122 * @vcrypto_dev: Pointer to virtio crypto device.
123 *
124 * Increment the vcrypto_dev refcount and if this is the first time
125 * incrementing it during this period the vcrypto_dev is in use,
126 * increment the module refcount too.
127 * To be used by virtio crypto device specific drivers.
128 *
129 * Return: 0 when successful, EFAULT when fail to bump module refcount
130 */
131int virtcrypto_dev_get(struct virtio_crypto *vcrypto_dev)
132{
133	if (atomic_add_return(1, &vcrypto_dev->ref_count) == 1)
134		if (!try_module_get(vcrypto_dev->owner))
135			return -EFAULT;
136	return 0;
137}
138
139/*
140 * virtcrypto_dev_put() - Decrement vcrypto_dev reference count
141 * @vcrypto_dev: Pointer to virtio crypto device.
142 *
143 * Decrement the vcrypto_dev refcount and if this is the last time
144 * decrementing it during this period the vcrypto_dev is in use,
145 * decrement the module refcount too.
146 * To be used by virtio crypto device specific drivers.
147 *
148 * Return: void
149 */
150void virtcrypto_dev_put(struct virtio_crypto *vcrypto_dev)
151{
152	if (atomic_sub_return(1, &vcrypto_dev->ref_count) == 0)
153		module_put(vcrypto_dev->owner);
154}
155
156/*
157 * virtcrypto_dev_started() - Check whether device has started
158 * @vcrypto_dev: Pointer to virtio crypto device.
159 *
160 * To be used by virtio crypto device specific drivers.
161 *
162 * Return: 1 when the device has started, 0 otherwise
163 */
164int virtcrypto_dev_started(struct virtio_crypto *vcrypto_dev)
165{
166	return (vcrypto_dev->status & VIRTIO_CRYPTO_S_HW_READY);
167}
168
169/*
170 * virtcrypto_get_dev_node() - Get vcrypto_dev on the node.
171 * @node:  Node id the driver works.
172 * @service: Crypto service that needs to be supported by the
173 *	      dev
174 * @algo: The algorithm number that needs to be supported by the
175 *	  dev
176 *
177 * Function returns the virtio crypto device used fewest on the node,
178 * and supports the given crypto service and algorithm.
179 *
180 * To be used by virtio crypto device specific drivers.
181 *
182 * Return: pointer to vcrypto_dev or NULL if not found.
183 */
184struct virtio_crypto *virtcrypto_get_dev_node(int node, uint32_t service,
185					      uint32_t algo)
186{
187	struct virtio_crypto *vcrypto_dev = NULL, *tmp_dev;
188	unsigned long best = ~0;
189	unsigned long ctr;
190
191	mutex_lock(&table_lock);
192	list_for_each_entry(tmp_dev, virtcrypto_devmgr_get_head(), list) {
193
194		if ((node == dev_to_node(&tmp_dev->vdev->dev) ||
195		     dev_to_node(&tmp_dev->vdev->dev) < 0) &&
196		    virtcrypto_dev_started(tmp_dev) &&
197		    virtcrypto_algo_is_supported(tmp_dev, service, algo)) {
198			ctr = atomic_read(&tmp_dev->ref_count);
199			if (best > ctr) {
200				vcrypto_dev = tmp_dev;
201				best = ctr;
202			}
203		}
204	}
205
206	if (!vcrypto_dev) {
207		pr_info("virtio_crypto: Could not find a device on node %d\n",
208				node);
209		/* Get any started device */
210		list_for_each_entry(tmp_dev,
211				virtcrypto_devmgr_get_head(), list) {
212			if (virtcrypto_dev_started(tmp_dev) &&
213			    virtcrypto_algo_is_supported(tmp_dev,
214			    service, algo)) {
215				vcrypto_dev = tmp_dev;
216				break;
217			}
218		}
219	}
220	mutex_unlock(&table_lock);
221	if (!vcrypto_dev)
222		return NULL;
223
224	virtcrypto_dev_get(vcrypto_dev);
225	return vcrypto_dev;
226}
227
228/*
229 * virtcrypto_dev_start() - Start virtio crypto device
230 * @vcrypto:    Pointer to virtio crypto device.
231 *
232 * Function notifies all the registered services that the virtio crypto device
233 * is ready to be used.
234 * To be used by virtio crypto device specific drivers.
235 *
236 * Return: 0 on success, EFAULT when fail to register algorithms
237 */
238int virtcrypto_dev_start(struct virtio_crypto *vcrypto)
239{
240	if (virtio_crypto_skcipher_algs_register(vcrypto)) {
241		pr_err("virtio_crypto: Failed to register crypto skcipher algs\n");
242		return -EFAULT;
243	}
244
245	if (virtio_crypto_akcipher_algs_register(vcrypto)) {
246		pr_err("virtio_crypto: Failed to register crypto akcipher algs\n");
247		virtio_crypto_skcipher_algs_unregister(vcrypto);
248		return -EFAULT;
249	}
250
251	return 0;
252}
253
254/*
255 * virtcrypto_dev_stop() - Stop virtio crypto device
256 * @vcrypto:    Pointer to virtio crypto device.
257 *
258 * Function notifies all the registered services that the virtio crypto device
259 * is ready to be used.
260 * To be used by virtio crypto device specific drivers.
261 *
262 * Return: void
263 */
264void virtcrypto_dev_stop(struct virtio_crypto *vcrypto)
265{
266	virtio_crypto_skcipher_algs_unregister(vcrypto);
267	virtio_crypto_akcipher_algs_unregister(vcrypto);
268}
269
270/*
271 * vcrypto_algo_is_supported()
272 * @vcrypto: Pointer to virtio crypto device.
273 * @service: The bit number for service validate.
274 *	      See VIRTIO_CRYPTO_SERVICE_*
275 * @algo : The bit number for the algorithm to validate.
276 *
277 *
278 * Validate if the virtio crypto device supports a service and
279 * algo.
280 *
281 * Return true if device supports a service and algo.
282 */
283
284bool virtcrypto_algo_is_supported(struct virtio_crypto *vcrypto,
285				  uint32_t service,
286				  uint32_t algo)
287{
288	uint32_t service_mask = 1u << service;
289	uint32_t algo_mask = 0;
290	bool low = true;
291
292	if (algo > 31) {
293		algo -= 32;
294		low = false;
295	}
296
297	if (!(vcrypto->crypto_services & service_mask))
298		return false;
299
300	switch (service) {
301	case VIRTIO_CRYPTO_SERVICE_CIPHER:
302		if (low)
303			algo_mask = vcrypto->cipher_algo_l;
304		else
305			algo_mask = vcrypto->cipher_algo_h;
306		break;
307
308	case VIRTIO_CRYPTO_SERVICE_HASH:
309		algo_mask = vcrypto->hash_algo;
310		break;
311
312	case VIRTIO_CRYPTO_SERVICE_MAC:
313		if (low)
314			algo_mask = vcrypto->mac_algo_l;
315		else
316			algo_mask = vcrypto->mac_algo_h;
317		break;
318
319	case VIRTIO_CRYPTO_SERVICE_AEAD:
320		algo_mask = vcrypto->aead_algo;
321		break;
322
323	case VIRTIO_CRYPTO_SERVICE_AKCIPHER:
324		algo_mask = vcrypto->akcipher_algo;
325		break;
326	}
327
328	if (!(algo_mask & (1u << algo)))
329		return false;
330
331	return true;
332}
333