Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 656 insertions, 0 deletions

diff --git a/drivers/crypto/virtio/virtio_crypto_algs.c b/drivers/crypto/virtio/virtio_crypto_algs.c
new file mode 100644
index 000000000..ae645c9d4
--- /dev/null
+++ b/drivers/crypto/virtio/virtio_crypto_algs.c
@@ -0,0 +1,656 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+ /* Algorithms supported by virtio crypto device
+  *
+  * Authors: Gonglei <arei.gonglei@huawei.com>
+  *
+  * Copyright 2016 HUAWEI TECHNOLOGIES CO., LTD.
+  */
+
+#include <linux/scatterlist.h>
+#include <crypto/algapi.h>
+#include <crypto/internal/skcipher.h>
+#include <linux/err.h>
+#include <crypto/scatterwalk.h>
+#include <linux/atomic.h>
+
+#include <uapi/linux/virtio_crypto.h>
+#include "virtio_crypto_common.h"
+
+
+struct virtio_crypto_skcipher_ctx {
+	struct crypto_engine_ctx enginectx;
+	struct virtio_crypto *vcrypto;
+	struct crypto_skcipher *tfm;
+
+	struct virtio_crypto_sym_session_info enc_sess_info;
+	struct virtio_crypto_sym_session_info dec_sess_info;
+};
+
+struct virtio_crypto_sym_request {
+	struct virtio_crypto_request base;
+
+	/* Cipher or aead */
+	uint32_t type;
+	struct virtio_crypto_skcipher_ctx *skcipher_ctx;
+	struct skcipher_request *skcipher_req;
+	uint8_t *iv;
+	/* Encryption? */
+	bool encrypt;
+};
+
+struct virtio_crypto_algo {
+	uint32_t algonum;
+	uint32_t service;
+	unsigned int active_devs;
+	struct skcipher_alg algo;
+};
+
+/*
+ * The algs_lock protects the below global virtio_crypto_active_devs
+ * and crypto algorithms registion.
+ */
+static DEFINE_MUTEX(algs_lock);
+static void virtio_crypto_skcipher_finalize_req(
+	struct virtio_crypto_sym_request *vc_sym_req,
+	struct skcipher_request *req,
+	int err);
+
+static void virtio_crypto_dataq_sym_callback
+		(struct virtio_crypto_request *vc_req, int len)
+{
+	struct virtio_crypto_sym_request *vc_sym_req =
+		container_of(vc_req, struct virtio_crypto_sym_request, base);
+	struct skcipher_request *ablk_req;
+	int error;
+
+	/* Finish the encrypt or decrypt process */
+	if (vc_sym_req->type == VIRTIO_CRYPTO_SYM_OP_CIPHER) {
+		switch (vc_req->status) {
+		case VIRTIO_CRYPTO_OK:
+			error = 0;
+			break;
+		case VIRTIO_CRYPTO_INVSESS:
+		case VIRTIO_CRYPTO_ERR:
+			error = -EINVAL;
+			break;
+		case VIRTIO_CRYPTO_BADMSG:
+			error = -EBADMSG;
+			break;
+		default:
+			error = -EIO;
+			break;
+		}
+		ablk_req = vc_sym_req->skcipher_req;
+		virtio_crypto_skcipher_finalize_req(vc_sym_req,
+							ablk_req, error);
+	}
+}
+
+static u64 virtio_crypto_alg_sg_nents_length(struct scatterlist *sg)
+{
+	u64 total = 0;
+
+	for (total = 0; sg; sg = sg_next(sg))
+		total += sg->length;
+
+	return total;
+}
+
+static int
+virtio_crypto_alg_validate_key(int key_len, uint32_t *alg)
+{
+	switch (key_len) {
+	case AES_KEYSIZE_128:
+	case AES_KEYSIZE_192:
+	case AES_KEYSIZE_256:
+		*alg = VIRTIO_CRYPTO_CIPHER_AES_CBC;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int virtio_crypto_alg_skcipher_init_session(
+		struct virtio_crypto_skcipher_ctx *ctx,
+		uint32_t alg, const uint8_t *key,
+		unsigned int keylen,
+		int encrypt)
+{
+	struct scatterlist outhdr, key_sg, inhdr, *sgs[3];
+	struct virtio_crypto *vcrypto = ctx->vcrypto;
+	int op = encrypt ? VIRTIO_CRYPTO_OP_ENCRYPT : VIRTIO_CRYPTO_OP_DECRYPT;
+	int err;
+	unsigned int num_out = 0, num_in = 0;
+	struct virtio_crypto_op_ctrl_req *ctrl;
+	struct virtio_crypto_session_input *input;
+	struct virtio_crypto_sym_create_session_req *sym_create_session;
+	struct virtio_crypto_ctrl_request *vc_ctrl_req;
+
+	/*
+	 * Avoid to do DMA from the stack, switch to using
+	 * dynamically-allocated for the key
+	 */
+	uint8_t *cipher_key = kmemdup(key, keylen, GFP_ATOMIC);
+
+	if (!cipher_key)
+		return -ENOMEM;
+
+	vc_ctrl_req = kzalloc(sizeof(*vc_ctrl_req), GFP_KERNEL);
+	if (!vc_ctrl_req) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	/* Pad ctrl header */
+	ctrl = &vc_ctrl_req->ctrl;
+	ctrl->header.opcode = cpu_to_le32(VIRTIO_CRYPTO_CIPHER_CREATE_SESSION);
+	ctrl->header.algo = cpu_to_le32(alg);
+	/* Set the default dataqueue id to 0 */
+	ctrl->header.queue_id = 0;
+
+	input = &vc_ctrl_req->input;
+	input->status = cpu_to_le32(VIRTIO_CRYPTO_ERR);
+	/* Pad cipher's parameters */
+	sym_create_session = &ctrl->u.sym_create_session;
+	sym_create_session->op_type = cpu_to_le32(VIRTIO_CRYPTO_SYM_OP_CIPHER);
+	sym_create_session->u.cipher.para.algo = ctrl->header.algo;
+	sym_create_session->u.cipher.para.keylen = cpu_to_le32(keylen);
+	sym_create_session->u.cipher.para.op = cpu_to_le32(op);
+
+	sg_init_one(&outhdr, ctrl, sizeof(*ctrl));
+	sgs[num_out++] = &outhdr;
+
+	/* Set key */
+	sg_init_one(&key_sg, cipher_key, keylen);
+	sgs[num_out++] = &key_sg;
+
+	/* Return status and session id back */
+	sg_init_one(&inhdr, input, sizeof(*input));
+	sgs[num_out + num_in++] = &inhdr;
+
+	err = virtio_crypto_ctrl_vq_request(vcrypto, sgs, num_out, num_in, vc_ctrl_req);
+	if (err < 0)
+		goto out;
+
+	if (le32_to_cpu(input->status) != VIRTIO_CRYPTO_OK) {
+		pr_err("virtio_crypto: Create session failed status: %u\n",
+			le32_to_cpu(input->status));
+		err = -EINVAL;
+		goto out;
+	}
+
+	if (encrypt)
+		ctx->enc_sess_info.session_id = le64_to_cpu(input->session_id);
+	else
+		ctx->dec_sess_info.session_id = le64_to_cpu(input->session_id);
+
+	err = 0;
+out:
+	kfree(vc_ctrl_req);
+	kfree_sensitive(cipher_key);
+	return err;
+}
+
+static int virtio_crypto_alg_skcipher_close_session(
+		struct virtio_crypto_skcipher_ctx *ctx,
+		int encrypt)
+{
+	struct scatterlist outhdr, status_sg, *sgs[2];
+	struct virtio_crypto_destroy_session_req *destroy_session;
+	struct virtio_crypto *vcrypto = ctx->vcrypto;
+	int err;
+	unsigned int num_out = 0, num_in = 0;
+	struct virtio_crypto_op_ctrl_req *ctrl;
+	struct virtio_crypto_inhdr *ctrl_status;
+	struct virtio_crypto_ctrl_request *vc_ctrl_req;
+
+	vc_ctrl_req = kzalloc(sizeof(*vc_ctrl_req), GFP_KERNEL);
+	if (!vc_ctrl_req)
+		return -ENOMEM;
+
+	ctrl_status = &vc_ctrl_req->ctrl_status;
+	ctrl_status->status = VIRTIO_CRYPTO_ERR;
+	/* Pad ctrl header */
+	ctrl = &vc_ctrl_req->ctrl;
+	ctrl->header.opcode = cpu_to_le32(VIRTIO_CRYPTO_CIPHER_DESTROY_SESSION);
+	/* Set the default virtqueue id to 0 */
+	ctrl->header.queue_id = 0;
+
+	destroy_session = &ctrl->u.destroy_session;
+
+	if (encrypt)
+		destroy_session->session_id = cpu_to_le64(ctx->enc_sess_info.session_id);
+	else
+		destroy_session->session_id = cpu_to_le64(ctx->dec_sess_info.session_id);
+
+	sg_init_one(&outhdr, ctrl, sizeof(*ctrl));
+	sgs[num_out++] = &outhdr;
+
+	/* Return status and session id back */
+	sg_init_one(&status_sg, &ctrl_status->status, sizeof(ctrl_status->status));
+	sgs[num_out + num_in++] = &status_sg;
+
+	err = virtio_crypto_ctrl_vq_request(vcrypto, sgs, num_out, num_in, vc_ctrl_req);
+	if (err < 0)
+		goto out;
+
+	if (ctrl_status->status != VIRTIO_CRYPTO_OK) {
+		pr_err("virtio_crypto: Close session failed status: %u, session_id: 0x%llx\n",
+			ctrl_status->status, destroy_session->session_id);
+
+		err = -EINVAL;
+		goto out;
+	}
+
+	err = 0;
+out:
+	kfree(vc_ctrl_req);
+	return err;
+}
+
+static int virtio_crypto_alg_skcipher_init_sessions(
+		struct virtio_crypto_skcipher_ctx *ctx,
+		const uint8_t *key, unsigned int keylen)
+{
+	uint32_t alg;
+	int ret;
+	struct virtio_crypto *vcrypto = ctx->vcrypto;
+
+	if (keylen > vcrypto->max_cipher_key_len) {
+		pr_err("virtio_crypto: the key is too long\n");
+		return -EINVAL;
+	}
+
+	if (virtio_crypto_alg_validate_key(keylen, &alg))
+		return -EINVAL;
+
+	/* Create encryption session */
+	ret = virtio_crypto_alg_skcipher_init_session(ctx,
+			alg, key, keylen, 1);
+	if (ret)
+		return ret;
+	/* Create decryption session */
+	ret = virtio_crypto_alg_skcipher_init_session(ctx,
+			alg, key, keylen, 0);
+	if (ret) {
+		virtio_crypto_alg_skcipher_close_session(ctx, 1);
+		return ret;
+	}
+	return 0;
+}
+
+/* Note: kernel crypto API realization */
+static int virtio_crypto_skcipher_setkey(struct crypto_skcipher *tfm,
+					 const uint8_t *key,
+					 unsigned int keylen)
+{
+	struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
+	uint32_t alg;
+	int ret;
+
+	ret = virtio_crypto_alg_validate_key(keylen, &alg);
+	if (ret)
+		return ret;
+
+	if (!ctx->vcrypto) {
+		/* New key */
+		int node = virtio_crypto_get_current_node();
+		struct virtio_crypto *vcrypto =
+				      virtcrypto_get_dev_node(node,
+				      VIRTIO_CRYPTO_SERVICE_CIPHER, alg);
+		if (!vcrypto) {
+			pr_err("virtio_crypto: Could not find a virtio device in the system or unsupported algo\n");
+			return -ENODEV;
+		}
+
+		ctx->vcrypto = vcrypto;
+	} else {
+		/* Rekeying, we should close the created sessions previously */
+		virtio_crypto_alg_skcipher_close_session(ctx, 1);
+		virtio_crypto_alg_skcipher_close_session(ctx, 0);
+	}
+
+	ret = virtio_crypto_alg_skcipher_init_sessions(ctx, key, keylen);
+	if (ret) {
+		virtcrypto_dev_put(ctx->vcrypto);
+		ctx->vcrypto = NULL;
+
+		return ret;
+	}
+
+	return 0;
+}
+
+static int
+__virtio_crypto_skcipher_do_req(struct virtio_crypto_sym_request *vc_sym_req,
+		struct skcipher_request *req,
+		struct data_queue *data_vq)
+{
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct virtio_crypto_skcipher_ctx *ctx = vc_sym_req->skcipher_ctx;
+	struct virtio_crypto_request *vc_req = &vc_sym_req->base;
+	unsigned int ivsize = crypto_skcipher_ivsize(tfm);
+	struct virtio_crypto *vcrypto = ctx->vcrypto;
+	struct virtio_crypto_op_data_req *req_data;
+	int src_nents, dst_nents;
+	int err;
+	unsigned long flags;
+	struct scatterlist outhdr, iv_sg, status_sg, **sgs;
+	u64 dst_len;
+	unsigned int num_out = 0, num_in = 0;
+	int sg_total;
+	uint8_t *iv;
+	struct scatterlist *sg;
+
+	src_nents = sg_nents_for_len(req->src, req->cryptlen);
+	if (src_nents < 0) {
+		pr_err("Invalid number of src SG.\n");
+		return src_nents;
+	}
+
+	dst_nents = sg_nents(req->dst);
+
+	pr_debug("virtio_crypto: Number of sgs (src_nents: %d, dst_nents: %d)\n",
+			src_nents, dst_nents);
+
+	/* Why 3?  outhdr + iv + inhdr */
+	sg_total = src_nents + dst_nents + 3;
+	sgs = kcalloc_node(sg_total, sizeof(*sgs), GFP_KERNEL,
+				dev_to_node(&vcrypto->vdev->dev));
+	if (!sgs)
+		return -ENOMEM;
+
+	req_data = kzalloc_node(sizeof(*req_data), GFP_KERNEL,
+				dev_to_node(&vcrypto->vdev->dev));
+	if (!req_data) {
+		kfree(sgs);
+		return -ENOMEM;
+	}
+
+	vc_req->req_data = req_data;
+	vc_sym_req->type = VIRTIO_CRYPTO_SYM_OP_CIPHER;
+	/* Head of operation */
+	if (vc_sym_req->encrypt) {
+		req_data->header.session_id =
+			cpu_to_le64(ctx->enc_sess_info.session_id);
+		req_data->header.opcode =
+			cpu_to_le32(VIRTIO_CRYPTO_CIPHER_ENCRYPT);
+	} else {
+		req_data->header.session_id =
+			cpu_to_le64(ctx->dec_sess_info.session_id);
+		req_data->header.opcode =
+			cpu_to_le32(VIRTIO_CRYPTO_CIPHER_DECRYPT);
+	}
+	req_data->u.sym_req.op_type = cpu_to_le32(VIRTIO_CRYPTO_SYM_OP_CIPHER);
+	req_data->u.sym_req.u.cipher.para.iv_len = cpu_to_le32(ivsize);
+	req_data->u.sym_req.u.cipher.para.src_data_len =
+			cpu_to_le32(req->cryptlen);
+
+	dst_len = virtio_crypto_alg_sg_nents_length(req->dst);
+	if (unlikely(dst_len > U32_MAX)) {
+		pr_err("virtio_crypto: The dst_len is beyond U32_MAX\n");
+		err = -EINVAL;
+		goto free;
+	}
+
+	dst_len = min_t(unsigned int, req->cryptlen, dst_len);
+	pr_debug("virtio_crypto: src_len: %u, dst_len: %llu\n",
+			req->cryptlen, dst_len);
+
+	if (unlikely(req->cryptlen + dst_len + ivsize +
+		sizeof(vc_req->status) > vcrypto->max_size)) {
+		pr_err("virtio_crypto: The length is too big\n");
+		err = -EINVAL;
+		goto free;
+	}
+
+	req_data->u.sym_req.u.cipher.para.dst_data_len =
+			cpu_to_le32((uint32_t)dst_len);
+
+	/* Outhdr */
+	sg_init_one(&outhdr, req_data, sizeof(*req_data));
+	sgs[num_out++] = &outhdr;
+
+	/* IV */
+
+	/*
+	 * Avoid to do DMA from the stack, switch to using
+	 * dynamically-allocated for the IV
+	 */
+	iv = kzalloc_node(ivsize, GFP_ATOMIC,
+				dev_to_node(&vcrypto->vdev->dev));
+	if (!iv) {
+		err = -ENOMEM;
+		goto free;
+	}
+	memcpy(iv, req->iv, ivsize);
+	if (!vc_sym_req->encrypt)
+		scatterwalk_map_and_copy(req->iv, req->src,
+					 req->cryptlen - AES_BLOCK_SIZE,
+					 AES_BLOCK_SIZE, 0);
+
+	sg_init_one(&iv_sg, iv, ivsize);
+	sgs[num_out++] = &iv_sg;
+	vc_sym_req->iv = iv;
+
+	/* Source data */
+	for (sg = req->src; src_nents; sg = sg_next(sg), src_nents--)
+		sgs[num_out++] = sg;
+
+	/* Destination data */
+	for (sg = req->dst; sg; sg = sg_next(sg))
+		sgs[num_out + num_in++] = sg;
+
+	/* Status */
+	sg_init_one(&status_sg, &vc_req->status, sizeof(vc_req->status));
+	sgs[num_out + num_in++] = &status_sg;
+
+	vc_req->sgs = sgs;
+
+	spin_lock_irqsave(&data_vq->lock, flags);
+	err = virtqueue_add_sgs(data_vq->vq, sgs, num_out,
+				num_in, vc_req, GFP_ATOMIC);
+	virtqueue_kick(data_vq->vq);
+	spin_unlock_irqrestore(&data_vq->lock, flags);
+	if (unlikely(err < 0))
+		goto free_iv;
+
+	return 0;
+
+free_iv:
+	kfree_sensitive(iv);
+free:
+	kfree_sensitive(req_data);
+	kfree(sgs);
+	return err;
+}
+
+static int virtio_crypto_skcipher_encrypt(struct skcipher_request *req)
+{
+	struct crypto_skcipher *atfm = crypto_skcipher_reqtfm(req);
+	struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(atfm);
+	struct virtio_crypto_sym_request *vc_sym_req =
+				skcipher_request_ctx(req);
+	struct virtio_crypto_request *vc_req = &vc_sym_req->base;
+	struct virtio_crypto *vcrypto = ctx->vcrypto;
+	/* Use the first data virtqueue as default */
+	struct data_queue *data_vq = &vcrypto->data_vq[0];
+
+	if (!req->cryptlen)
+		return 0;
+	if (req->cryptlen % AES_BLOCK_SIZE)
+		return -EINVAL;
+
+	vc_req->dataq = data_vq;
+	vc_req->alg_cb = virtio_crypto_dataq_sym_callback;
+	vc_sym_req->skcipher_ctx = ctx;
+	vc_sym_req->skcipher_req = req;
+	vc_sym_req->encrypt = true;
+
+	return crypto_transfer_skcipher_request_to_engine(data_vq->engine, req);
+}
+
+static int virtio_crypto_skcipher_decrypt(struct skcipher_request *req)
+{
+	struct crypto_skcipher *atfm = crypto_skcipher_reqtfm(req);
+	struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(atfm);
+	struct virtio_crypto_sym_request *vc_sym_req =
+				skcipher_request_ctx(req);
+	struct virtio_crypto_request *vc_req = &vc_sym_req->base;
+	struct virtio_crypto *vcrypto = ctx->vcrypto;
+	/* Use the first data virtqueue as default */
+	struct data_queue *data_vq = &vcrypto->data_vq[0];
+
+	if (!req->cryptlen)
+		return 0;
+	if (req->cryptlen % AES_BLOCK_SIZE)
+		return -EINVAL;
+
+	vc_req->dataq = data_vq;
+	vc_req->alg_cb = virtio_crypto_dataq_sym_callback;
+	vc_sym_req->skcipher_ctx = ctx;
+	vc_sym_req->skcipher_req = req;
+	vc_sym_req->encrypt = false;
+
+	return crypto_transfer_skcipher_request_to_engine(data_vq->engine, req);
+}
+
+static int virtio_crypto_skcipher_init(struct crypto_skcipher *tfm)
+{
+	struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+	crypto_skcipher_set_reqsize(tfm, sizeof(struct virtio_crypto_sym_request));
+	ctx->tfm = tfm;
+
+	ctx->enginectx.op.do_one_request = virtio_crypto_skcipher_crypt_req;
+	ctx->enginectx.op.prepare_request = NULL;
+	ctx->enginectx.op.unprepare_request = NULL;
+	return 0;
+}
+
+static void virtio_crypto_skcipher_exit(struct crypto_skcipher *tfm)
+{
+	struct virtio_crypto_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+	if (!ctx->vcrypto)
+		return;
+
+	virtio_crypto_alg_skcipher_close_session(ctx, 1);
+	virtio_crypto_alg_skcipher_close_session(ctx, 0);
+	virtcrypto_dev_put(ctx->vcrypto);
+	ctx->vcrypto = NULL;
+}
+
+int virtio_crypto_skcipher_crypt_req(
+	struct crypto_engine *engine, void *vreq)
+{
+	struct skcipher_request *req = container_of(vreq, struct skcipher_request, base);
+	struct virtio_crypto_sym_request *vc_sym_req =
+				skcipher_request_ctx(req);
+	struct virtio_crypto_request *vc_req = &vc_sym_req->base;
+	struct data_queue *data_vq = vc_req->dataq;
+	int ret;
+
+	ret = __virtio_crypto_skcipher_do_req(vc_sym_req, req, data_vq);
+	if (ret < 0)
+		return ret;
+
+	virtqueue_kick(data_vq->vq);
+
+	return 0;
+}
+
+static void virtio_crypto_skcipher_finalize_req(
+	struct virtio_crypto_sym_request *vc_sym_req,
+	struct skcipher_request *req,
+	int err)
+{
+	if (vc_sym_req->encrypt)
+		scatterwalk_map_and_copy(req->iv, req->dst,
+					 req->cryptlen - AES_BLOCK_SIZE,
+					 AES_BLOCK_SIZE, 0);
+	kfree_sensitive(vc_sym_req->iv);
+	virtcrypto_clear_request(&vc_sym_req->base);
+
+	crypto_finalize_skcipher_request(vc_sym_req->base.dataq->engine,
+					   req, err);
+}
+
+static struct virtio_crypto_algo virtio_crypto_algs[] = { {
+	.algonum = VIRTIO_CRYPTO_CIPHER_AES_CBC,
+	.service = VIRTIO_CRYPTO_SERVICE_CIPHER,
+	.algo = {
+		.base.cra_name		= "cbc(aes)",
+		.base.cra_driver_name	= "virtio_crypto_aes_cbc",
+		.base.cra_priority	= 150,
+		.base.cra_flags		= CRYPTO_ALG_ASYNC |
+					  CRYPTO_ALG_ALLOCATES_MEMORY,
+		.base.cra_blocksize	= AES_BLOCK_SIZE,
+		.base.cra_ctxsize	= sizeof(struct virtio_crypto_skcipher_ctx),
+		.base.cra_module	= THIS_MODULE,
+		.init			= virtio_crypto_skcipher_init,
+		.exit			= virtio_crypto_skcipher_exit,
+		.setkey			= virtio_crypto_skcipher_setkey,
+		.decrypt		= virtio_crypto_skcipher_decrypt,
+		.encrypt		= virtio_crypto_skcipher_encrypt,
+		.min_keysize		= AES_MIN_KEY_SIZE,
+		.max_keysize		= AES_MAX_KEY_SIZE,
+		.ivsize			= AES_BLOCK_SIZE,
+	},
+} };
+
+int virtio_crypto_algs_register(struct virtio_crypto *vcrypto)
+{
+	int ret = 0;
+	int i = 0;
+
+	mutex_lock(&algs_lock);
+
+	for (i = 0; i < ARRAY_SIZE(virtio_crypto_algs); i++) {
+
+		uint32_t service = virtio_crypto_algs[i].service;
+		uint32_t algonum = virtio_crypto_algs[i].algonum;
+
+		if (!virtcrypto_algo_is_supported(vcrypto, service, algonum))
+			continue;
+
+		if (virtio_crypto_algs[i].active_devs == 0) {
+			ret = crypto_register_skcipher(&virtio_crypto_algs[i].algo);
+			if (ret)
+				goto unlock;
+		}
+
+		virtio_crypto_algs[i].active_devs++;
+		dev_info(&vcrypto->vdev->dev, "Registered algo %s\n",
+			 virtio_crypto_algs[i].algo.base.cra_name);
+	}
+
+unlock:
+	mutex_unlock(&algs_lock);
+	return ret;
+}
+
+void virtio_crypto_algs_unregister(struct virtio_crypto *vcrypto)
+{
+	int i = 0;
+
+	mutex_lock(&algs_lock);
+
+	for (i = 0; i < ARRAY_SIZE(virtio_crypto_algs); i++) {
+
+		uint32_t service = virtio_crypto_algs[i].service;
+		uint32_t algonum = virtio_crypto_algs[i].algonum;
+
+		if (virtio_crypto_algs[i].active_devs == 0 ||
+		    !virtcrypto_algo_is_supported(vcrypto, service, algonum))
+			continue;
+
+		if (virtio_crypto_algs[i].active_devs == 1)
+			crypto_unregister_skcipher(&virtio_crypto_algs[i].algo);
+
+		virtio_crypto_algs[i].active_devs--;
+	}
+
+	mutex_unlock(&algs_lock);
+}