xref: /linux/drivers/crypto/virtio/virtio_crypto_skcipher_algs.c (revision 24bce201d79807b668bf9d9e0aca801c5c0d5f78)
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 		return -EINVAL;
243 	}
244 
245 	err = 0;
246 out:
247 	kfree(vc_ctrl_req);
248 	return err;
249 }
250 
251 static int virtio_crypto_alg_skcipher_init_sessions(
252 		struct virtio_crypto_skcipher_ctx *ctx,
253 		const uint8_t *key, unsigned int keylen)
254 {
255 	uint32_t alg;
256 	int ret;
257 	struct virtio_crypto *vcrypto = ctx->vcrypto;
258 
259 	if (keylen > vcrypto->max_cipher_key_len) {
260 		pr_err("virtio_crypto: the key is too long\n");
261 		return -EINVAL;
262 	}
263 
264 	if (virtio_crypto_alg_validate_key(keylen, &alg))
265 		return -EINVAL;
266 
267 	/* Create encryption session */
268 	ret = virtio_crypto_alg_skcipher_init_session(ctx,
269 			alg, key, keylen, 1);
270 	if (ret)
271 		return ret;
272 	/* Create decryption session */
273 	ret = virtio_crypto_alg_skcipher_init_session(ctx,
274 			alg, key, keylen, 0);
275 	if (ret) {
276 		virtio_crypto_alg_skcipher_close_session(ctx, 1);
277 		return ret;
278 	}
279 	return 0;
280 }
281 
282 /* Note: kernel crypto API realization */
283 static int virtio_crypto_skcipher_setkey(struct crypto_skcipher *tfm,
284 					 const uint8_t *key,
285 					 unsigned int keylen)
286 {
287 	struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
288 	uint32_t alg;
289 	int ret;
290 
291 	ret = virtio_crypto_alg_validate_key(keylen, &alg);
292 	if (ret)
293 		return ret;
294 
295 	if (!ctx->vcrypto) {
296 		/* New key */
297 		int node = virtio_crypto_get_current_node();
298 		struct virtio_crypto *vcrypto =
299 				      virtcrypto_get_dev_node(node,
300 				      VIRTIO_CRYPTO_SERVICE_CIPHER, alg);
301 		if (!vcrypto) {
302 			pr_err("virtio_crypto: Could not find a virtio device in the system or unsupported algo\n");
303 			return -ENODEV;
304 		}
305 
306 		ctx->vcrypto = vcrypto;
307 	} else {
308 		/* Rekeying, we should close the created sessions previously */
309 		virtio_crypto_alg_skcipher_close_session(ctx, 1);
310 		virtio_crypto_alg_skcipher_close_session(ctx, 0);
311 	}
312 
313 	ret = virtio_crypto_alg_skcipher_init_sessions(ctx, key, keylen);
314 	if (ret) {
315 		virtcrypto_dev_put(ctx->vcrypto);
316 		ctx->vcrypto = NULL;
317 
318 		return ret;
319 	}
320 
321 	return 0;
322 }
323 
324 static int
325 __virtio_crypto_skcipher_do_req(struct virtio_crypto_sym_request *vc_sym_req,
326 		struct skcipher_request *req,
327 		struct data_queue *data_vq)
328 {
329 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
330 	struct virtio_crypto_skcipher_ctx *ctx = vc_sym_req->skcipher_ctx;
331 	struct virtio_crypto_request *vc_req = &vc_sym_req->base;
332 	unsigned int ivsize = crypto_skcipher_ivsize(tfm);
333 	struct virtio_crypto *vcrypto = ctx->vcrypto;
334 	struct virtio_crypto_op_data_req *req_data;
335 	int src_nents, dst_nents;
336 	int err;
337 	unsigned long flags;
338 	struct scatterlist outhdr, iv_sg, status_sg, **sgs;
339 	u64 dst_len;
340 	unsigned int num_out = 0, num_in = 0;
341 	int sg_total;
342 	uint8_t *iv;
343 	struct scatterlist *sg;
344 
345 	src_nents = sg_nents_for_len(req->src, req->cryptlen);
346 	if (src_nents < 0) {
347 		pr_err("Invalid number of src SG.\n");
348 		return src_nents;
349 	}
350 
351 	dst_nents = sg_nents(req->dst);
352 
353 	pr_debug("virtio_crypto: Number of sgs (src_nents: %d, dst_nents: %d)\n",
354 			src_nents, dst_nents);
355 
356 	/* Why 3?  outhdr + iv + inhdr */
357 	sg_total = src_nents + dst_nents + 3;
358 	sgs = kcalloc_node(sg_total, sizeof(*sgs), GFP_KERNEL,
359 				dev_to_node(&vcrypto->vdev->dev));
360 	if (!sgs)
361 		return -ENOMEM;
362 
363 	req_data = kzalloc_node(sizeof(*req_data), GFP_KERNEL,
364 				dev_to_node(&vcrypto->vdev->dev));
365 	if (!req_data) {
366 		kfree(sgs);
367 		return -ENOMEM;
368 	}
369 
370 	vc_req->req_data = req_data;
371 	vc_sym_req->type = VIRTIO_CRYPTO_SYM_OP_CIPHER;
372 	/* Head of operation */
373 	if (vc_sym_req->encrypt) {
374 		req_data->header.session_id =
375 			cpu_to_le64(ctx->enc_sess_info.session_id);
376 		req_data->header.opcode =
377 			cpu_to_le32(VIRTIO_CRYPTO_CIPHER_ENCRYPT);
378 	} else {
379 		req_data->header.session_id =
380 			cpu_to_le64(ctx->dec_sess_info.session_id);
381 		req_data->header.opcode =
382 			cpu_to_le32(VIRTIO_CRYPTO_CIPHER_DECRYPT);
383 	}
384 	req_data->u.sym_req.op_type = cpu_to_le32(VIRTIO_CRYPTO_SYM_OP_CIPHER);
385 	req_data->u.sym_req.u.cipher.para.iv_len = cpu_to_le32(ivsize);
386 	req_data->u.sym_req.u.cipher.para.src_data_len =
387 			cpu_to_le32(req->cryptlen);
388 
389 	dst_len = virtio_crypto_alg_sg_nents_length(req->dst);
390 	if (unlikely(dst_len > U32_MAX)) {
391 		pr_err("virtio_crypto: The dst_len is beyond U32_MAX\n");
392 		err = -EINVAL;
393 		goto free;
394 	}
395 
396 	dst_len = min_t(unsigned int, req->cryptlen, dst_len);
397 	pr_debug("virtio_crypto: src_len: %u, dst_len: %llu\n",
398 			req->cryptlen, dst_len);
399 
400 	if (unlikely(req->cryptlen + dst_len + ivsize +
401 		sizeof(vc_req->status) > vcrypto->max_size)) {
402 		pr_err("virtio_crypto: The length is too big\n");
403 		err = -EINVAL;
404 		goto free;
405 	}
406 
407 	req_data->u.sym_req.u.cipher.para.dst_data_len =
408 			cpu_to_le32((uint32_t)dst_len);
409 
410 	/* Outhdr */
411 	sg_init_one(&outhdr, req_data, sizeof(*req_data));
412 	sgs[num_out++] = &outhdr;
413 
414 	/* IV */
415 
416 	/*
417 	 * Avoid to do DMA from the stack, switch to using
418 	 * dynamically-allocated for the IV
419 	 */
420 	iv = kzalloc_node(ivsize, GFP_ATOMIC,
421 				dev_to_node(&vcrypto->vdev->dev));
422 	if (!iv) {
423 		err = -ENOMEM;
424 		goto free;
425 	}
426 	memcpy(iv, req->iv, ivsize);
427 	if (!vc_sym_req->encrypt)
428 		scatterwalk_map_and_copy(req->iv, req->src,
429 					 req->cryptlen - AES_BLOCK_SIZE,
430 					 AES_BLOCK_SIZE, 0);
431 
432 	sg_init_one(&iv_sg, iv, ivsize);
433 	sgs[num_out++] = &iv_sg;
434 	vc_sym_req->iv = iv;
435 
436 	/* Source data */
437 	for (sg = req->src; src_nents; sg = sg_next(sg), src_nents--)
438 		sgs[num_out++] = sg;
439 
440 	/* Destination data */
441 	for (sg = req->dst; sg; sg = sg_next(sg))
442 		sgs[num_out + num_in++] = sg;
443 
444 	/* Status */
445 	sg_init_one(&status_sg, &vc_req->status, sizeof(vc_req->status));
446 	sgs[num_out + num_in++] = &status_sg;
447 
448 	vc_req->sgs = sgs;
449 
450 	spin_lock_irqsave(&data_vq->lock, flags);
451 	err = virtqueue_add_sgs(data_vq->vq, sgs, num_out,
452 				num_in, vc_req, GFP_ATOMIC);
453 	virtqueue_kick(data_vq->vq);
454 	spin_unlock_irqrestore(&data_vq->lock, flags);
455 	if (unlikely(err < 0))
456 		goto free_iv;
457 
458 	return 0;
459 
460 free_iv:
461 	kfree_sensitive(iv);
462 free:
463 	kfree_sensitive(req_data);
464 	kfree(sgs);
465 	return err;
466 }
467 
468 static int virtio_crypto_skcipher_encrypt(struct skcipher_request *req)
469 {
470 	struct crypto_skcipher *atfm = crypto_skcipher_reqtfm(req);
471 	struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(atfm);
472 	struct virtio_crypto_sym_request *vc_sym_req =
473 				skcipher_request_ctx(req);
474 	struct virtio_crypto_request *vc_req = &vc_sym_req->base;
475 	struct virtio_crypto *vcrypto = ctx->vcrypto;
476 	/* Use the first data virtqueue as default */
477 	struct data_queue *data_vq = &vcrypto->data_vq[0];
478 
479 	if (!req->cryptlen)
480 		return 0;
481 	if (req->cryptlen % AES_BLOCK_SIZE)
482 		return -EINVAL;
483 
484 	vc_req->dataq = data_vq;
485 	vc_req->alg_cb = virtio_crypto_dataq_sym_callback;
486 	vc_sym_req->skcipher_ctx = ctx;
487 	vc_sym_req->skcipher_req = req;
488 	vc_sym_req->encrypt = true;
489 
490 	return crypto_transfer_skcipher_request_to_engine(data_vq->engine, req);
491 }
492 
493 static int virtio_crypto_skcipher_decrypt(struct skcipher_request *req)
494 {
495 	struct crypto_skcipher *atfm = crypto_skcipher_reqtfm(req);
496 	struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(atfm);
497 	struct virtio_crypto_sym_request *vc_sym_req =
498 				skcipher_request_ctx(req);
499 	struct virtio_crypto_request *vc_req = &vc_sym_req->base;
500 	struct virtio_crypto *vcrypto = ctx->vcrypto;
501 	/* Use the first data virtqueue as default */
502 	struct data_queue *data_vq = &vcrypto->data_vq[0];
503 
504 	if (!req->cryptlen)
505 		return 0;
506 	if (req->cryptlen % AES_BLOCK_SIZE)
507 		return -EINVAL;
508 
509 	vc_req->dataq = data_vq;
510 	vc_req->alg_cb = virtio_crypto_dataq_sym_callback;
511 	vc_sym_req->skcipher_ctx = ctx;
512 	vc_sym_req->skcipher_req = req;
513 	vc_sym_req->encrypt = false;
514 
515 	return crypto_transfer_skcipher_request_to_engine(data_vq->engine, req);
516 }
517 
518 static int virtio_crypto_skcipher_init(struct crypto_skcipher *tfm)
519 {
520 	struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
521 
522 	crypto_skcipher_set_reqsize(tfm, sizeof(struct virtio_crypto_sym_request));
523 	ctx->tfm = tfm;
524 
525 	ctx->enginectx.op.do_one_request = virtio_crypto_skcipher_crypt_req;
526 	ctx->enginectx.op.prepare_request = NULL;
527 	ctx->enginectx.op.unprepare_request = NULL;
528 	return 0;
529 }
530 
531 static void virtio_crypto_skcipher_exit(struct crypto_skcipher *tfm)
532 {
533 	struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
534 
535 	if (!ctx->vcrypto)
536 		return;
537 
538 	virtio_crypto_alg_skcipher_close_session(ctx, 1);
539 	virtio_crypto_alg_skcipher_close_session(ctx, 0);
540 	virtcrypto_dev_put(ctx->vcrypto);
541 	ctx->vcrypto = NULL;
542 }
543 
544 int virtio_crypto_skcipher_crypt_req(
545 	struct crypto_engine *engine, void *vreq)
546 {
547 	struct skcipher_request *req = container_of(vreq, struct skcipher_request, base);
548 	struct virtio_crypto_sym_request *vc_sym_req =
549 				skcipher_request_ctx(req);
550 	struct virtio_crypto_request *vc_req = &vc_sym_req->base;
551 	struct data_queue *data_vq = vc_req->dataq;
552 	int ret;
553 
554 	ret = __virtio_crypto_skcipher_do_req(vc_sym_req, req, data_vq);
555 	if (ret < 0)
556 		return ret;
557 
558 	virtqueue_kick(data_vq->vq);
559 
560 	return 0;
561 }
562 
563 static void virtio_crypto_skcipher_finalize_req(
564 	struct virtio_crypto_sym_request *vc_sym_req,
565 	struct skcipher_request *req,
566 	int err)
567 {
568 	if (vc_sym_req->encrypt)
569 		scatterwalk_map_and_copy(req->iv, req->dst,
570 					 req->cryptlen - AES_BLOCK_SIZE,
571 					 AES_BLOCK_SIZE, 0);
572 	kfree_sensitive(vc_sym_req->iv);
573 	virtcrypto_clear_request(&vc_sym_req->base);
574 
575 	crypto_finalize_skcipher_request(vc_sym_req->base.dataq->engine,
576 					   req, err);
577 }
578 
579 static struct virtio_crypto_algo virtio_crypto_algs[] = { {
580 	.algonum = VIRTIO_CRYPTO_CIPHER_AES_CBC,
581 	.service = VIRTIO_CRYPTO_SERVICE_CIPHER,
582 	.algo = {
583 		.base.cra_name		= "cbc(aes)",
584 		.base.cra_driver_name	= "virtio_crypto_aes_cbc",
585 		.base.cra_priority	= 150,
586 		.base.cra_flags		= CRYPTO_ALG_ASYNC |
587 					  CRYPTO_ALG_ALLOCATES_MEMORY,
588 		.base.cra_blocksize	= AES_BLOCK_SIZE,
589 		.base.cra_ctxsize	= sizeof(struct virtio_crypto_skcipher_ctx),
590 		.base.cra_module	= THIS_MODULE,
591 		.init			= virtio_crypto_skcipher_init,
592 		.exit			= virtio_crypto_skcipher_exit,
593 		.setkey			= virtio_crypto_skcipher_setkey,
594 		.decrypt		= virtio_crypto_skcipher_decrypt,
595 		.encrypt		= virtio_crypto_skcipher_encrypt,
596 		.min_keysize		= AES_MIN_KEY_SIZE,
597 		.max_keysize		= AES_MAX_KEY_SIZE,
598 		.ivsize			= AES_BLOCK_SIZE,
599 	},
600 } };
601 
602 int virtio_crypto_skcipher_algs_register(struct virtio_crypto *vcrypto)
603 {
604 	int ret = 0;
605 	int i = 0;
606 
607 	mutex_lock(&algs_lock);
608 
609 	for (i = 0; i < ARRAY_SIZE(virtio_crypto_algs); i++) {
610 
611 		uint32_t service = virtio_crypto_algs[i].service;
612 		uint32_t algonum = virtio_crypto_algs[i].algonum;
613 
614 		if (!virtcrypto_algo_is_supported(vcrypto, service, algonum))
615 			continue;
616 
617 		if (virtio_crypto_algs[i].active_devs == 0) {
618 			ret = crypto_register_skcipher(&virtio_crypto_algs[i].algo);
619 			if (ret)
620 				goto unlock;
621 		}
622 
623 		virtio_crypto_algs[i].active_devs++;
624 		dev_info(&vcrypto->vdev->dev, "Registered algo %s\n",
625 			 virtio_crypto_algs[i].algo.base.cra_name);
626 	}
627 
628 unlock:
629 	mutex_unlock(&algs_lock);
630 	return ret;
631 }
632 
633 void virtio_crypto_skcipher_algs_unregister(struct virtio_crypto *vcrypto)
634 {
635 	int i = 0;
636 
637 	mutex_lock(&algs_lock);
638 
639 	for (i = 0; i < ARRAY_SIZE(virtio_crypto_algs); i++) {
640 
641 		uint32_t service = virtio_crypto_algs[i].service;
642 		uint32_t algonum = virtio_crypto_algs[i].algonum;
643 
644 		if (virtio_crypto_algs[i].active_devs == 0 ||
645 		    !virtcrypto_algo_is_supported(vcrypto, service, algonum))
646 			continue;
647 
648 		if (virtio_crypto_algs[i].active_devs == 1)
649 			crypto_unregister_skcipher(&virtio_crypto_algs[i].algo);
650 
651 		virtio_crypto_algs[i].active_devs--;
652 	}
653 
654 	mutex_unlock(&algs_lock);
655 }
656