1 // SPDX-License-Identifier: GPL-2.0-or-later
2  /* Algorithms supported by virtio crypto device
3   *
4   * Authors: Gonglei <arei.gonglei@huawei.com>
5   *
6   * Copyright 2016 HUAWEI TECHNOLOGIES CO., LTD.
7   */
8 
9 #include <linux/scatterlist.h>
10 #include <crypto/algapi.h>
11 #include <crypto/internal/skcipher.h>
12 #include <linux/err.h>
13 #include <crypto/scatterwalk.h>
14 #include <linux/atomic.h>
15 
16 #include <uapi/linux/virtio_crypto.h>
17 #include "virtio_crypto_common.h"
18 
19 
20 struct virtio_crypto_skcipher_ctx {
21 	struct crypto_engine_ctx enginectx;
22 	struct virtio_crypto *vcrypto;
23 	struct crypto_skcipher *tfm;
24 
25 	struct virtio_crypto_sym_session_info enc_sess_info;
26 	struct virtio_crypto_sym_session_info dec_sess_info;
27 };
28 
29 struct virtio_crypto_sym_request {
30 	struct virtio_crypto_request base;
31 
32 	/* Cipher or aead */
33 	uint32_t type;
34 	struct virtio_crypto_skcipher_ctx *skcipher_ctx;
35 	struct skcipher_request *skcipher_req;
36 	uint8_t *iv;
37 	/* Encryption? */
38 	bool encrypt;
39 };
40 
41 struct virtio_crypto_algo {
42 	uint32_t algonum;
43 	uint32_t service;
44 	unsigned int active_devs;
45 	struct skcipher_alg algo;
46 };
47 
48 /*
49  * The algs_lock protects the below global virtio_crypto_active_devs
50  * and crypto algorithms registion.
51  */
52 static DEFINE_MUTEX(algs_lock);
53 static void virtio_crypto_skcipher_finalize_req(
54 	struct virtio_crypto_sym_request *vc_sym_req,
55 	struct skcipher_request *req,
56 	int err);
57 
58 static void virtio_crypto_dataq_sym_callback
59 		(struct virtio_crypto_request *vc_req, int len)
60 {
61 	struct virtio_crypto_sym_request *vc_sym_req =
62 		container_of(vc_req, struct virtio_crypto_sym_request, base);
63 	struct skcipher_request *ablk_req;
64 	int error;
65 
66 	/* Finish the encrypt or decrypt process */
67 	if (vc_sym_req->type == VIRTIO_CRYPTO_SYM_OP_CIPHER) {
68 		switch (vc_req->status) {
69 		case VIRTIO_CRYPTO_OK:
70 			error = 0;
71 			break;
72 		case VIRTIO_CRYPTO_INVSESS:
73 		case VIRTIO_CRYPTO_ERR:
74 			error = -EINVAL;
75 			break;
76 		case VIRTIO_CRYPTO_BADMSG:
77 			error = -EBADMSG;
78 			break;
79 		default:
80 			error = -EIO;
81 			break;
82 		}
83 		ablk_req = vc_sym_req->skcipher_req;
84 		virtio_crypto_skcipher_finalize_req(vc_sym_req,
85 							ablk_req, error);
86 	}
87 }
88 
89 static u64 virtio_crypto_alg_sg_nents_length(struct scatterlist *sg)
90 {
91 	u64 total = 0;
92 
93 	for (total = 0; sg; sg = sg_next(sg))
94 		total += sg->length;
95 
96 	return total;
97 }
98 
99 static int
100 virtio_crypto_alg_validate_key(int key_len, uint32_t *alg)
101 {
102 	switch (key_len) {
103 	case AES_KEYSIZE_128:
104 	case AES_KEYSIZE_192:
105 	case AES_KEYSIZE_256:
106 		*alg = VIRTIO_CRYPTO_CIPHER_AES_CBC;
107 		break;
108 	default:
109 		return -EINVAL;
110 	}
111 	return 0;
112 }
113 
114 static int virtio_crypto_alg_skcipher_init_session(
115 		struct virtio_crypto_skcipher_ctx *ctx,
116 		uint32_t alg, const uint8_t *key,
117 		unsigned int keylen,
118 		int encrypt)
119 {
120 	struct scatterlist outhdr, key_sg, inhdr, *sgs[3];
121 	struct virtio_crypto *vcrypto = ctx->vcrypto;
122 	int op = encrypt ? VIRTIO_CRYPTO_OP_ENCRYPT : VIRTIO_CRYPTO_OP_DECRYPT;
123 	int err;
124 	unsigned int num_out = 0, num_in = 0;
125 	struct virtio_crypto_op_ctrl_req *ctrl;
126 	struct virtio_crypto_session_input *input;
127 	struct virtio_crypto_sym_create_session_req *sym_create_session;
128 	struct virtio_crypto_ctrl_request *vc_ctrl_req;
129 
130 	/*
131 	 * Avoid to do DMA from the stack, switch to using
132 	 * dynamically-allocated for the key
133 	 */
134 	uint8_t *cipher_key = kmemdup(key, keylen, GFP_ATOMIC);
135 
136 	if (!cipher_key)
137 		return -ENOMEM;
138 
139 	vc_ctrl_req = kzalloc(sizeof(*vc_ctrl_req), GFP_KERNEL);
140 	if (!vc_ctrl_req) {
141 		err = -ENOMEM;
142 		goto out;
143 	}
144 
145 	/* Pad ctrl header */
146 	ctrl = &vc_ctrl_req->ctrl;
147 	ctrl->header.opcode = cpu_to_le32(VIRTIO_CRYPTO_CIPHER_CREATE_SESSION);
148 	ctrl->header.algo = cpu_to_le32(alg);
149 	/* Set the default dataqueue id to 0 */
150 	ctrl->header.queue_id = 0;
151 
152 	input = &vc_ctrl_req->input;
153 	input->status = cpu_to_le32(VIRTIO_CRYPTO_ERR);
154 	/* Pad cipher's parameters */
155 	sym_create_session = &ctrl->u.sym_create_session;
156 	sym_create_session->op_type = cpu_to_le32(VIRTIO_CRYPTO_SYM_OP_CIPHER);
157 	sym_create_session->u.cipher.para.algo = ctrl->header.algo;
158 	sym_create_session->u.cipher.para.keylen = cpu_to_le32(keylen);
159 	sym_create_session->u.cipher.para.op = cpu_to_le32(op);
160 
161 	sg_init_one(&outhdr, ctrl, sizeof(*ctrl));
162 	sgs[num_out++] = &outhdr;
163 
164 	/* Set key */
165 	sg_init_one(&key_sg, cipher_key, keylen);
166 	sgs[num_out++] = &key_sg;
167 
168 	/* Return status and session id back */
169 	sg_init_one(&inhdr, input, sizeof(*input));
170 	sgs[num_out + num_in++] = &inhdr;
171 
172 	err = virtio_crypto_ctrl_vq_request(vcrypto, sgs, num_out, num_in, vc_ctrl_req);
173 	if (err < 0)
174 		goto out;
175 
176 	if (le32_to_cpu(input->status) != VIRTIO_CRYPTO_OK) {
177 		pr_err("virtio_crypto: Create session failed status: %u\n",
178 			le32_to_cpu(input->status));
179 		err = -EINVAL;
180 		goto out;
181 	}
182 
183 	if (encrypt)
184 		ctx->enc_sess_info.session_id = le64_to_cpu(input->session_id);
185 	else
186 		ctx->dec_sess_info.session_id = le64_to_cpu(input->session_id);
187 
188 	err = 0;
189 out:
190 	kfree(vc_ctrl_req);
191 	kfree_sensitive(cipher_key);
192 	return err;
193 }
194 
195 static int virtio_crypto_alg_skcipher_close_session(
196 		struct virtio_crypto_skcipher_ctx *ctx,
197 		int encrypt)
198 {
199 	struct scatterlist outhdr, status_sg, *sgs[2];
200 	struct virtio_crypto_destroy_session_req *destroy_session;
201 	struct virtio_crypto *vcrypto = ctx->vcrypto;
202 	int err;
203 	unsigned int num_out = 0, num_in = 0;
204 	struct virtio_crypto_op_ctrl_req *ctrl;
205 	struct virtio_crypto_inhdr *ctrl_status;
206 	struct virtio_crypto_ctrl_request *vc_ctrl_req;
207 
208 	vc_ctrl_req = kzalloc(sizeof(*vc_ctrl_req), GFP_KERNEL);
209 	if (!vc_ctrl_req)
210 		return -ENOMEM;
211 
212 	ctrl_status = &vc_ctrl_req->ctrl_status;
213 	ctrl_status->status = VIRTIO_CRYPTO_ERR;
214 	/* Pad ctrl header */
215 	ctrl = &vc_ctrl_req->ctrl;
216 	ctrl->header.opcode = cpu_to_le32(VIRTIO_CRYPTO_CIPHER_DESTROY_SESSION);
217 	/* Set the default virtqueue id to 0 */
218 	ctrl->header.queue_id = 0;
219 
220 	destroy_session = &ctrl->u.destroy_session;
221 
222 	if (encrypt)
223 		destroy_session->session_id = cpu_to_le64(ctx->enc_sess_info.session_id);
224 	else
225 		destroy_session->session_id = cpu_to_le64(ctx->dec_sess_info.session_id);
226 
227 	sg_init_one(&outhdr, ctrl, sizeof(*ctrl));
228 	sgs[num_out++] = &outhdr;
229 
230 	/* Return status and session id back */
231 	sg_init_one(&status_sg, &ctrl_status->status, sizeof(ctrl_status->status));
232 	sgs[num_out + num_in++] = &status_sg;
233 
234 	err = virtio_crypto_ctrl_vq_request(vcrypto, sgs, num_out, num_in, vc_ctrl_req);
235 	if (err < 0)
236 		goto out;
237 
238 	if (ctrl_status->status != VIRTIO_CRYPTO_OK) {
239 		pr_err("virtio_crypto: Close session failed status: %u, session_id: 0x%llx\n",
240 			ctrl_status->status, destroy_session->session_id);
241 
242 		err = -EINVAL;
243 		goto out;
244 	}
245 
246 	err = 0;
247 out:
248 	kfree(vc_ctrl_req);
249 	return err;
250 }
251 
252 static int virtio_crypto_alg_skcipher_init_sessions(
253 		struct virtio_crypto_skcipher_ctx *ctx,
254 		const uint8_t *key, unsigned int keylen)
255 {
256 	uint32_t alg;
257 	int ret;
258 	struct virtio_crypto *vcrypto = ctx->vcrypto;
259 
260 	if (keylen > vcrypto->max_cipher_key_len) {
261 		pr_err("virtio_crypto: the key is too long\n");
262 		return -EINVAL;
263 	}
264 
265 	if (virtio_crypto_alg_validate_key(keylen, &alg))
266 		return -EINVAL;
267 
268 	/* Create encryption session */
269 	ret = virtio_crypto_alg_skcipher_init_session(ctx,
270 			alg, key, keylen, 1);
271 	if (ret)
272 		return ret;
273 	/* Create decryption session */
274 	ret = virtio_crypto_alg_skcipher_init_session(ctx,
275 			alg, key, keylen, 0);
276 	if (ret) {
277 		virtio_crypto_alg_skcipher_close_session(ctx, 1);
278 		return ret;
279 	}
280 	return 0;
281 }
282 
283 /* Note: kernel crypto API realization */
284 static int virtio_crypto_skcipher_setkey(struct crypto_skcipher *tfm,
285 					 const uint8_t *key,
286 					 unsigned int keylen)
287 {
288 	struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
289 	uint32_t alg;
290 	int ret;
291 
292 	ret = virtio_crypto_alg_validate_key(keylen, &alg);
293 	if (ret)
294 		return ret;
295 
296 	if (!ctx->vcrypto) {
297 		/* New key */
298 		int node = virtio_crypto_get_current_node();
299 		struct virtio_crypto *vcrypto =
300 				      virtcrypto_get_dev_node(node,
301 				      VIRTIO_CRYPTO_SERVICE_CIPHER, alg);
302 		if (!vcrypto) {
303 			pr_err("virtio_crypto: Could not find a virtio device in the system or unsupported algo\n");
304 			return -ENODEV;
305 		}
306 
307 		ctx->vcrypto = vcrypto;
308 	} else {
309 		/* Rekeying, we should close the created sessions previously */
310 		virtio_crypto_alg_skcipher_close_session(ctx, 1);
311 		virtio_crypto_alg_skcipher_close_session(ctx, 0);
312 	}
313 
314 	ret = virtio_crypto_alg_skcipher_init_sessions(ctx, key, keylen);
315 	if (ret) {
316 		virtcrypto_dev_put(ctx->vcrypto);
317 		ctx->vcrypto = NULL;
318 
319 		return ret;
320 	}
321 
322 	return 0;
323 }
324 
325 static int
326 __virtio_crypto_skcipher_do_req(struct virtio_crypto_sym_request *vc_sym_req,
327 		struct skcipher_request *req,
328 		struct data_queue *data_vq)
329 {
330 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
331 	struct virtio_crypto_skcipher_ctx *ctx = vc_sym_req->skcipher_ctx;
332 	struct virtio_crypto_request *vc_req = &vc_sym_req->base;
333 	unsigned int ivsize = crypto_skcipher_ivsize(tfm);
334 	struct virtio_crypto *vcrypto = ctx->vcrypto;
335 	struct virtio_crypto_op_data_req *req_data;
336 	int src_nents, dst_nents;
337 	int err;
338 	unsigned long flags;
339 	struct scatterlist outhdr, iv_sg, status_sg, **sgs;
340 	u64 dst_len;
341 	unsigned int num_out = 0, num_in = 0;
342 	int sg_total;
343 	uint8_t *iv;
344 	struct scatterlist *sg;
345 
346 	src_nents = sg_nents_for_len(req->src, req->cryptlen);
347 	if (src_nents < 0) {
348 		pr_err("Invalid number of src SG.\n");
349 		return src_nents;
350 	}
351 
352 	dst_nents = sg_nents(req->dst);
353 
354 	pr_debug("virtio_crypto: Number of sgs (src_nents: %d, dst_nents: %d)\n",
355 			src_nents, dst_nents);
356 
357 	/* Why 3?  outhdr + iv + inhdr */
358 	sg_total = src_nents + dst_nents + 3;
359 	sgs = kcalloc_node(sg_total, sizeof(*sgs), GFP_KERNEL,
360 				dev_to_node(&vcrypto->vdev->dev));
361 	if (!sgs)
362 		return -ENOMEM;
363 
364 	req_data = kzalloc_node(sizeof(*req_data), GFP_KERNEL,
365 				dev_to_node(&vcrypto->vdev->dev));
366 	if (!req_data) {
367 		kfree(sgs);
368 		return -ENOMEM;
369 	}
370 
371 	vc_req->req_data = req_data;
372 	vc_sym_req->type = VIRTIO_CRYPTO_SYM_OP_CIPHER;
373 	/* Head of operation */
374 	if (vc_sym_req->encrypt) {
375 		req_data->header.session_id =
376 			cpu_to_le64(ctx->enc_sess_info.session_id);
377 		req_data->header.opcode =
378 			cpu_to_le32(VIRTIO_CRYPTO_CIPHER_ENCRYPT);
379 	} else {
380 		req_data->header.session_id =
381 			cpu_to_le64(ctx->dec_sess_info.session_id);
382 		req_data->header.opcode =
383 			cpu_to_le32(VIRTIO_CRYPTO_CIPHER_DECRYPT);
384 	}
385 	req_data->u.sym_req.op_type = cpu_to_le32(VIRTIO_CRYPTO_SYM_OP_CIPHER);
386 	req_data->u.sym_req.u.cipher.para.iv_len = cpu_to_le32(ivsize);
387 	req_data->u.sym_req.u.cipher.para.src_data_len =
388 			cpu_to_le32(req->cryptlen);
389 
390 	dst_len = virtio_crypto_alg_sg_nents_length(req->dst);
391 	if (unlikely(dst_len > U32_MAX)) {
392 		pr_err("virtio_crypto: The dst_len is beyond U32_MAX\n");
393 		err = -EINVAL;
394 		goto free;
395 	}
396 
397 	dst_len = min_t(unsigned int, req->cryptlen, dst_len);
398 	pr_debug("virtio_crypto: src_len: %u, dst_len: %llu\n",
399 			req->cryptlen, dst_len);
400 
401 	if (unlikely(req->cryptlen + dst_len + ivsize +
402 		sizeof(vc_req->status) > vcrypto->max_size)) {
403 		pr_err("virtio_crypto: The length is too big\n");
404 		err = -EINVAL;
405 		goto free;
406 	}
407 
408 	req_data->u.sym_req.u.cipher.para.dst_data_len =
409 			cpu_to_le32((uint32_t)dst_len);
410 
411 	/* Outhdr */
412 	sg_init_one(&outhdr, req_data, sizeof(*req_data));
413 	sgs[num_out++] = &outhdr;
414 
415 	/* IV */
416 
417 	/*
418 	 * Avoid to do DMA from the stack, switch to using
419 	 * dynamically-allocated for the IV
420 	 */
421 	iv = kzalloc_node(ivsize, GFP_ATOMIC,
422 				dev_to_node(&vcrypto->vdev->dev));
423 	if (!iv) {
424 		err = -ENOMEM;
425 		goto free;
426 	}
427 	memcpy(iv, req->iv, ivsize);
428 	if (!vc_sym_req->encrypt)
429 		scatterwalk_map_and_copy(req->iv, req->src,
430 					 req->cryptlen - AES_BLOCK_SIZE,
431 					 AES_BLOCK_SIZE, 0);
432 
433 	sg_init_one(&iv_sg, iv, ivsize);
434 	sgs[num_out++] = &iv_sg;
435 	vc_sym_req->iv = iv;
436 
437 	/* Source data */
438 	for (sg = req->src; src_nents; sg = sg_next(sg), src_nents--)
439 		sgs[num_out++] = sg;
440 
441 	/* Destination data */
442 	for (sg = req->dst; sg; sg = sg_next(sg))
443 		sgs[num_out + num_in++] = sg;
444 
445 	/* Status */
446 	sg_init_one(&status_sg, &vc_req->status, sizeof(vc_req->status));
447 	sgs[num_out + num_in++] = &status_sg;
448 
449 	vc_req->sgs = sgs;
450 
451 	spin_lock_irqsave(&data_vq->lock, flags);
452 	err = virtqueue_add_sgs(data_vq->vq, sgs, num_out,
453 				num_in, vc_req, GFP_ATOMIC);
454 	virtqueue_kick(data_vq->vq);
455 	spin_unlock_irqrestore(&data_vq->lock, flags);
456 	if (unlikely(err < 0))
457 		goto free_iv;
458 
459 	return 0;
460 
461 free_iv:
462 	kfree_sensitive(iv);
463 free:
464 	kfree_sensitive(req_data);
465 	kfree(sgs);
466 	return err;
467 }
468 
469 static int virtio_crypto_skcipher_encrypt(struct skcipher_request *req)
470 {
471 	struct crypto_skcipher *atfm = crypto_skcipher_reqtfm(req);
472 	struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(atfm);
473 	struct virtio_crypto_sym_request *vc_sym_req =
474 				skcipher_request_ctx(req);
475 	struct virtio_crypto_request *vc_req = &vc_sym_req->base;
476 	struct virtio_crypto *vcrypto = ctx->vcrypto;
477 	/* Use the first data virtqueue as default */
478 	struct data_queue *data_vq = &vcrypto->data_vq[0];
479 
480 	if (!req->cryptlen)
481 		return 0;
482 	if (req->cryptlen % AES_BLOCK_SIZE)
483 		return -EINVAL;
484 
485 	vc_req->dataq = data_vq;
486 	vc_req->alg_cb = virtio_crypto_dataq_sym_callback;
487 	vc_sym_req->skcipher_ctx = ctx;
488 	vc_sym_req->skcipher_req = req;
489 	vc_sym_req->encrypt = true;
490 
491 	return crypto_transfer_skcipher_request_to_engine(data_vq->engine, req);
492 }
493 
494 static int virtio_crypto_skcipher_decrypt(struct skcipher_request *req)
495 {
496 	struct crypto_skcipher *atfm = crypto_skcipher_reqtfm(req);
497 	struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(atfm);
498 	struct virtio_crypto_sym_request *vc_sym_req =
499 				skcipher_request_ctx(req);
500 	struct virtio_crypto_request *vc_req = &vc_sym_req->base;
501 	struct virtio_crypto *vcrypto = ctx->vcrypto;
502 	/* Use the first data virtqueue as default */
503 	struct data_queue *data_vq = &vcrypto->data_vq[0];
504 
505 	if (!req->cryptlen)
506 		return 0;
507 	if (req->cryptlen % AES_BLOCK_SIZE)
508 		return -EINVAL;
509 
510 	vc_req->dataq = data_vq;
511 	vc_req->alg_cb = virtio_crypto_dataq_sym_callback;
512 	vc_sym_req->skcipher_ctx = ctx;
513 	vc_sym_req->skcipher_req = req;
514 	vc_sym_req->encrypt = false;
515 
516 	return crypto_transfer_skcipher_request_to_engine(data_vq->engine, req);
517 }
518 
519 static int virtio_crypto_skcipher_init(struct crypto_skcipher *tfm)
520 {
521 	struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
522 
523 	crypto_skcipher_set_reqsize(tfm, sizeof(struct virtio_crypto_sym_request));
524 	ctx->tfm = tfm;
525 
526 	ctx->enginectx.op.do_one_request = virtio_crypto_skcipher_crypt_req;
527 	ctx->enginectx.op.prepare_request = NULL;
528 	ctx->enginectx.op.unprepare_request = NULL;
529 	return 0;
530 }
531 
532 static void virtio_crypto_skcipher_exit(struct crypto_skcipher *tfm)
533 {
534 	struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
535 
536 	if (!ctx->vcrypto)
537 		return;
538 
539 	virtio_crypto_alg_skcipher_close_session(ctx, 1);
540 	virtio_crypto_alg_skcipher_close_session(ctx, 0);
541 	virtcrypto_dev_put(ctx->vcrypto);
542 	ctx->vcrypto = NULL;
543 }
544 
545 int virtio_crypto_skcipher_crypt_req(
546 	struct crypto_engine *engine, void *vreq)
547 {
548 	struct skcipher_request *req = container_of(vreq, struct skcipher_request, base);
549 	struct virtio_crypto_sym_request *vc_sym_req =
550 				skcipher_request_ctx(req);
551 	struct virtio_crypto_request *vc_req = &vc_sym_req->base;
552 	struct data_queue *data_vq = vc_req->dataq;
553 	int ret;
554 
555 	ret = __virtio_crypto_skcipher_do_req(vc_sym_req, req, data_vq);
556 	if (ret < 0)
557 		return ret;
558 
559 	virtqueue_kick(data_vq->vq);
560 
561 	return 0;
562 }
563 
564 static void virtio_crypto_skcipher_finalize_req(
565 	struct virtio_crypto_sym_request *vc_sym_req,
566 	struct skcipher_request *req,
567 	int err)
568 {
569 	if (vc_sym_req->encrypt)
570 		scatterwalk_map_and_copy(req->iv, req->dst,
571 					 req->cryptlen - AES_BLOCK_SIZE,
572 					 AES_BLOCK_SIZE, 0);
573 	kfree_sensitive(vc_sym_req->iv);
574 	virtcrypto_clear_request(&vc_sym_req->base);
575 
576 	crypto_finalize_skcipher_request(vc_sym_req->base.dataq->engine,
577 					   req, err);
578 }
579 
580 static struct virtio_crypto_algo virtio_crypto_algs[] = { {
581 	.algonum = VIRTIO_CRYPTO_CIPHER_AES_CBC,
582 	.service = VIRTIO_CRYPTO_SERVICE_CIPHER,
583 	.algo = {
584 		.base.cra_name		= "cbc(aes)",
585 		.base.cra_driver_name	= "virtio_crypto_aes_cbc",
586 		.base.cra_priority	= 150,
587 		.base.cra_flags		= CRYPTO_ALG_ASYNC |
588 					  CRYPTO_ALG_ALLOCATES_MEMORY,
589 		.base.cra_blocksize	= AES_BLOCK_SIZE,
590 		.base.cra_ctxsize	= sizeof(struct virtio_crypto_skcipher_ctx),
591 		.base.cra_module	= THIS_MODULE,
592 		.init			= virtio_crypto_skcipher_init,
593 		.exit			= virtio_crypto_skcipher_exit,
594 		.setkey			= virtio_crypto_skcipher_setkey,
595 		.decrypt		= virtio_crypto_skcipher_decrypt,
596 		.encrypt		= virtio_crypto_skcipher_encrypt,
597 		.min_keysize		= AES_MIN_KEY_SIZE,
598 		.max_keysize		= AES_MAX_KEY_SIZE,
599 		.ivsize			= AES_BLOCK_SIZE,
600 	},
601 } };
602 
603 int virtio_crypto_skcipher_algs_register(struct virtio_crypto *vcrypto)
604 {
605 	int ret = 0;
606 	int i = 0;
607 
608 	mutex_lock(&algs_lock);
609 
610 	for (i = 0; i < ARRAY_SIZE(virtio_crypto_algs); i++) {
611 
612 		uint32_t service = virtio_crypto_algs[i].service;
613 		uint32_t algonum = virtio_crypto_algs[i].algonum;
614 
615 		if (!virtcrypto_algo_is_supported(vcrypto, service, algonum))
616 			continue;
617 
618 		if (virtio_crypto_algs[i].active_devs == 0) {
619 			ret = crypto_register_skcipher(&virtio_crypto_algs[i].algo);
620 			if (ret)
621 				goto unlock;
622 		}
623 
624 		virtio_crypto_algs[i].active_devs++;
625 		dev_info(&vcrypto->vdev->dev, "Registered algo %s\n",
626 			 virtio_crypto_algs[i].algo.base.cra_name);
627 	}
628 
629 unlock:
630 	mutex_unlock(&algs_lock);
631 	return ret;
632 }
633 
634 void virtio_crypto_skcipher_algs_unregister(struct virtio_crypto *vcrypto)
635 {
636 	int i = 0;
637 
638 	mutex_lock(&algs_lock);
639 
640 	for (i = 0; i < ARRAY_SIZE(virtio_crypto_algs); i++) {
641 
642 		uint32_t service = virtio_crypto_algs[i].service;
643 		uint32_t algonum = virtio_crypto_algs[i].algonum;
644 
645 		if (virtio_crypto_algs[i].active_devs == 0 ||
646 		    !virtcrypto_algo_is_supported(vcrypto, service, algonum))
647 			continue;
648 
649 		if (virtio_crypto_algs[i].active_devs == 1)
650 			crypto_unregister_skcipher(&virtio_crypto_algs[i].algo);
651 
652 		virtio_crypto_algs[i].active_devs--;
653 	}
654 
655 	mutex_unlock(&algs_lock);
656 }
657