[RFC,v1,2/2] crypto/virtio-crypto: Register an algo only if it's supported

Commit Message

Farhan Ali June 8, 2018, 7:08 p.m. UTC

From: Farhan Ali <[e-mail]>

Register a crypto algo with the Linux crypto layer only if
the algorithm is supported by the backend virtio-crypto
device.

Also route crypto requests to a virtio-crypto
device, only if it can support the requested service and
algorithm.

Signed-off-by: Farhan Ali <[e-mail]>
---
 drivers/crypto/virtio/virtio_crypto_algs.c   | 110 ++++++++++++++++++---------
 drivers/crypto/virtio/virtio_crypto_common.h |  11 ++-
 drivers/crypto/virtio/virtio_crypto_mgr.c    |  81 ++++++++++++++++++--
 3 files changed, 158 insertions(+), 44 deletions(-)

Comments

Gonglei (Arei) June 11, 2018, 8:48 a.m. UTC | #1

> -----Original Message-----
> From: Farhan Ali [mailto:[e-mail]]
> Sent: Saturday, June 09, 2018 3:09 AM
> To: [e-mail]; [e-mail]
> Cc: [e-mail]; [e-mail]; Gonglei (Arei)
> <[e-mail]>; longpeng <[e-mail]>;
> [e-mail]; [e-mail]; [e-mail];
> [e-mail]
> Subject: [RFC v1 2/2] crypto/virtio-crypto: Register an algo only if it's supported
> 
> From: Farhan Ali <[e-mail]>
> 
> Register a crypto algo with the Linux crypto layer only if
> the algorithm is supported by the backend virtio-crypto
> device.
> 
> Also route crypto requests to a virtio-crypto
> device, only if it can support the requested service and
> algorithm.
> 
> Signed-off-by: Farhan Ali <[e-mail]>
> ---
>  drivers/crypto/virtio/virtio_crypto_algs.c   | 110
> ++++++++++++++++++---------
>  drivers/crypto/virtio/virtio_crypto_common.h |  11 ++-
>  drivers/crypto/virtio/virtio_crypto_mgr.c    |  81 ++++++++++++++++++--
>  3 files changed, 158 insertions(+), 44 deletions(-)
> 
> diff --git a/drivers/crypto/virtio/virtio_crypto_algs.c
> b/drivers/crypto/virtio/virtio_crypto_algs.c
> index ba190cf..fef112a 100644
> --- a/drivers/crypto/virtio/virtio_crypto_algs.c
> +++ b/drivers/crypto/virtio/virtio_crypto_algs.c
> @@ -49,12 +49,18 @@ struct virtio_crypto_sym_request {
>  	bool encrypt;
>  };
> 
> +struct virtio_crypto_algo {
> +	uint32_t algonum;
> +	uint32_t service;
> +	unsigned int active_devs;
> +	struct crypto_alg algo;
> +};
> +
>  /*
>   * The algs_lock protects the below global virtio_crypto_active_devs
>   * and crypto algorithms registion.
>   */
>  static DEFINE_MUTEX(algs_lock);
> -static unsigned int virtio_crypto_active_devs;
>  static void virtio_crypto_ablkcipher_finalize_req(
>  	struct virtio_crypto_sym_request *vc_sym_req,
>  	struct ablkcipher_request *req,
> @@ -312,13 +318,19 @@ static int virtio_crypto_ablkcipher_setkey(struct
> crypto_ablkcipher *tfm,
>  					 unsigned int keylen)
>  {
>  	struct virtio_crypto_ablkcipher_ctx *ctx = crypto_ablkcipher_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);
> +				      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\n");

We'd better change the above error message now. What about:
 " virtio_crypto: Could not find a virtio device in the system or unsupported algo" ?

Regards,
-Gonglei

Farhan Ali June 12, 2018, 5:07 p.m. UTC | #2

On 06/11/2018 04:48 AM, Gonglei (Arei) wrote:
> 
> 
>> -----Original Message-----
>> From: Farhan Ali [mailto:[e-mail]]
>> Sent: Saturday, June 09, 2018 3:09 AM
>> To: [e-mail]; [e-mail]
>> Cc: [e-mail]; [e-mail]; Gonglei (Arei)
>> <[e-mail]>; longpeng <[e-mail]>;
>> [e-mail]; [e-mail]; [e-mail];
>> [e-mail]
>> Subject: [RFC v1 2/2] crypto/virtio-crypto: Register an algo only if it's supported
>>
>> From: Farhan Ali <[e-mail]>
>>
>> Register a crypto algo with the Linux crypto layer only if
>> the algorithm is supported by the backend virtio-crypto
>> device.
>>
>> Also route crypto requests to a virtio-crypto
>> device, only if it can support the requested service and
>> algorithm.
>>
>> Signed-off-by: Farhan Ali <[e-mail]>
>> ---
>>   drivers/crypto/virtio/virtio_crypto_algs.c   | 110
>> ++++++++++++++++++---------
>>   drivers/crypto/virtio/virtio_crypto_common.h |  11 ++-
>>   drivers/crypto/virtio/virtio_crypto_mgr.c    |  81 ++++++++++++++++++--
>>   3 files changed, 158 insertions(+), 44 deletions(-)
>>
>> diff --git a/drivers/crypto/virtio/virtio_crypto_algs.c
>> b/drivers/crypto/virtio/virtio_crypto_algs.c
>> index ba190cf..fef112a 100644
>> --- a/drivers/crypto/virtio/virtio_crypto_algs.c
>> +++ b/drivers/crypto/virtio/virtio_crypto_algs.c
>> @@ -49,12 +49,18 @@ struct virtio_crypto_sym_request {
>>   	bool encrypt;
>>   };
>>
>> +struct virtio_crypto_algo {
>> +	uint32_t algonum;
>> +	uint32_t service;
>> +	unsigned int active_devs;
>> +	struct crypto_alg algo;
>> +};
>> +
>>   /*
>>    * The algs_lock protects the below global virtio_crypto_active_devs
>>    * and crypto algorithms registion.
>>    */
>>   static DEFINE_MUTEX(algs_lock);
>> -static unsigned int virtio_crypto_active_devs;
>>   static void virtio_crypto_ablkcipher_finalize_req(
>>   	struct virtio_crypto_sym_request *vc_sym_req,
>>   	struct ablkcipher_request *req,
>> @@ -312,13 +318,19 @@ static int virtio_crypto_ablkcipher_setkey(struct
>> crypto_ablkcipher *tfm,
>>   					 unsigned int keylen)
>>   {
>>   	struct virtio_crypto_ablkcipher_ctx *ctx = crypto_ablkcipher_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);
>> +				      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\n");
> 
> We'd better change the above error message now. What about:
>   " virtio_crypto: Could not find a virtio device in the system or unsupported algo" ?
> 
> Regards,
> -Gonglei


Sure, I will update the error message. But other than that does the rest 
of the code looks good to you?

Thanks
Farhan

> 
> 
> 
>

Gonglei (Arei) June 13, 2018, 12:31 a.m. UTC | #3

> -----Original Message-----

> From: Farhan Ali [mailto:[e-mail]]

> Sent: Wednesday, June 13, 2018 1:08 AM

> To: Gonglei (Arei) <[e-mail]>; [e-mail];

> [e-mail]

> Cc: [e-mail]; [e-mail]; longpeng

> <[e-mail]>; [e-mail]; [e-mail];

> [e-mail]

> Subject: Re: [RFC v1 2/2] crypto/virtio-crypto: Register an algo only if it's

> supported

> 

> 

> 

> On 06/11/2018 04:48 AM, Gonglei (Arei) wrote:

> >

> >

> >> -----Original Message-----

> >> From: Farhan Ali [mailto:[e-mail]]

> >> Sent: Saturday, June 09, 2018 3:09 AM

> >> To: [e-mail]; [e-mail]

> >> Cc: [e-mail]; [e-mail]; Gonglei (Arei)

> >> <[e-mail]>; longpeng <[e-mail]>;

> >> [e-mail]; [e-mail]; [e-mail];

> >> [e-mail]

> >> Subject: [RFC v1 2/2] crypto/virtio-crypto: Register an algo only if it's

> supported

> >>

> >> From: Farhan Ali <[e-mail]>

> >>

> >> Register a crypto algo with the Linux crypto layer only if

> >> the algorithm is supported by the backend virtio-crypto

> >> device.

> >>

> >> Also route crypto requests to a virtio-crypto

> >> device, only if it can support the requested service and

> >> algorithm.

> >>

> >> Signed-off-by: Farhan Ali <[e-mail]>

> >> ---

> >>   drivers/crypto/virtio/virtio_crypto_algs.c   | 110

> >> ++++++++++++++++++---------

> >>   drivers/crypto/virtio/virtio_crypto_common.h |  11 ++-

> >>   drivers/crypto/virtio/virtio_crypto_mgr.c    |  81

> ++++++++++++++++++--

> >>   3 files changed, 158 insertions(+), 44 deletions(-)

> >>

> >> diff --git a/drivers/crypto/virtio/virtio_crypto_algs.c

> >> b/drivers/crypto/virtio/virtio_crypto_algs.c

> >> index ba190cf..fef112a 100644

> >> --- a/drivers/crypto/virtio/virtio_crypto_algs.c

> >> +++ b/drivers/crypto/virtio/virtio_crypto_algs.c

> >> @@ -49,12 +49,18 @@ struct virtio_crypto_sym_request {

> >>   	bool encrypt;

> >>   };

> >>

> >> +struct virtio_crypto_algo {

> >> +	uint32_t algonum;

> >> +	uint32_t service;

> >> +	unsigned int active_devs;

> >> +	struct crypto_alg algo;

> >> +};

> >> +

> >>   /*

> >>    * The algs_lock protects the below global virtio_crypto_active_devs

> >>    * and crypto algorithms registion.

> >>    */

> >>   static DEFINE_MUTEX(algs_lock);

> >> -static unsigned int virtio_crypto_active_devs;

> >>   static void virtio_crypto_ablkcipher_finalize_req(

> >>   	struct virtio_crypto_sym_request *vc_sym_req,

> >>   	struct ablkcipher_request *req,

> >> @@ -312,13 +318,19 @@ static int virtio_crypto_ablkcipher_setkey(struct

> >> crypto_ablkcipher *tfm,

> >>   					 unsigned int keylen)

> >>   {

> >>   	struct virtio_crypto_ablkcipher_ctx *ctx =

> crypto_ablkcipher_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);

> >> +				      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\n");

> >

> > We'd better change the above error message now. What about:

> >   " virtio_crypto: Could not find a virtio device in the system or unsupported

> algo" ?

> >

> > Regards,

> > -Gonglei

> 

> 

> Sure, I will update the error message. But other than that does the rest

> of the code looks good to you?

> 

Yes, good work. You can add my ack in v2:

Acked-by: Gonglei <[e-mail]>


Regards,
-Gonglei

Patch

diff --git a/drivers/crypto/virtio/virtio_crypto_algs.c b/drivers/crypto/virtio/virtio_crypto_algs.c
index ba190cf..fef112a 100644
--- a/drivers/crypto/virtio/virtio_crypto_algs.c
+++ b/drivers/crypto/virtio/virtio_crypto_algs.c
@@ -49,12 +49,18 @@  struct virtio_crypto_sym_request {
 	bool encrypt;
 };
 
+struct virtio_crypto_algo {
+	uint32_t algonum;
+	uint32_t service;
+	unsigned int active_devs;
+	struct crypto_alg algo;
+};
+
 /*
  * The algs_lock protects the below global virtio_crypto_active_devs
  * and crypto algorithms registion.
  */
 static DEFINE_MUTEX(algs_lock);
-static unsigned int virtio_crypto_active_devs;
 static void virtio_crypto_ablkcipher_finalize_req(
 	struct virtio_crypto_sym_request *vc_sym_req,
 	struct ablkcipher_request *req,
@@ -312,13 +318,19 @@  static int virtio_crypto_ablkcipher_setkey(struct crypto_ablkcipher *tfm,
 					 unsigned int keylen)
 {
 	struct virtio_crypto_ablkcipher_ctx *ctx = crypto_ablkcipher_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);
+				      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\n");
 			return -ENODEV;
@@ -571,57 +583,85 @@  static void virtio_crypto_ablkcipher_finalize_req(
 	virtcrypto_clear_request(&vc_sym_req->base);
 }
 
-static struct crypto_alg virtio_crypto_algs[] = { {
-	.cra_name = "cbc(aes)",
-	.cra_driver_name = "virtio_crypto_aes_cbc",
-	.cra_priority = 150,
-	.cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
-	.cra_blocksize = AES_BLOCK_SIZE,
-	.cra_ctxsize  = sizeof(struct virtio_crypto_ablkcipher_ctx),
-	.cra_alignmask = 0,
-	.cra_module = THIS_MODULE,
-	.cra_type = &crypto_ablkcipher_type,
-	.cra_init = virtio_crypto_ablkcipher_init,
-	.cra_exit = virtio_crypto_ablkcipher_exit,
-	.cra_u = {
-	   .ablkcipher = {
-			.setkey = virtio_crypto_ablkcipher_setkey,
-			.decrypt = virtio_crypto_ablkcipher_decrypt,
-			.encrypt = virtio_crypto_ablkcipher_encrypt,
-			.min_keysize = AES_MIN_KEY_SIZE,
-			.max_keysize = AES_MAX_KEY_SIZE,
-			.ivsize = AES_BLOCK_SIZE,
+static struct virtio_crypto_algo virtio_crypto_algs[] = { {
+	.algonum = VIRTIO_CRYPTO_CIPHER_AES_CBC,
+	.service = VIRTIO_CRYPTO_SERVICE_CIPHER,
+	.algo = {
+		.cra_name = "cbc(aes)",
+		.cra_driver_name = "virtio_crypto_aes_cbc",
+		.cra_priority = 150,
+		.cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
+		.cra_blocksize = AES_BLOCK_SIZE,
+		.cra_ctxsize  = sizeof(struct virtio_crypto_ablkcipher_ctx),
+		.cra_alignmask = 0,
+		.cra_module = THIS_MODULE,
+		.cra_type = &crypto_ablkcipher_type,
+		.cra_init = virtio_crypto_ablkcipher_init,
+		.cra_exit = virtio_crypto_ablkcipher_exit,
+		.cra_u = {
+			.ablkcipher = {
+				.setkey = virtio_crypto_ablkcipher_setkey,
+				.decrypt = virtio_crypto_ablkcipher_decrypt,
+				.encrypt = virtio_crypto_ablkcipher_encrypt,
+				.min_keysize = AES_MIN_KEY_SIZE,
+				.max_keysize = AES_MAX_KEY_SIZE,
+				.ivsize = AES_BLOCK_SIZE,
+			},
 		},
 	},
 } };
 
-int virtio_crypto_algs_register(void)
+int virtio_crypto_algs_register(struct virtio_crypto *vcrypto)
 {
 	int ret = 0;
+	int i = 0;
 
 	mutex_lock(&algs_lock);
-	if (++virtio_crypto_active_devs != 1)
-		goto unlock;
 
-	ret = crypto_register_algs(virtio_crypto_algs,
-			ARRAY_SIZE(virtio_crypto_algs));
-	if (ret)
-		virtio_crypto_active_devs--;
+	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_alg(&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.cra_name);
+	}
 
 unlock:
 	mutex_unlock(&algs_lock);
 	return ret;
 }
 
-void virtio_crypto_algs_unregister(void)
+void virtio_crypto_algs_unregister(struct virtio_crypto *vcrypto)
 {
+	int i = 0;
+
 	mutex_lock(&algs_lock);
-	if (--virtio_crypto_active_devs != 0)
-		goto unlock;
 
-	crypto_unregister_algs(virtio_crypto_algs,
-			ARRAY_SIZE(virtio_crypto_algs));
+	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_alg(&virtio_crypto_algs[i].algo);
+
+		virtio_crypto_algs[i].active_devs--;
+	}
 
-unlock:
 	mutex_unlock(&algs_lock);
 }
diff --git a/drivers/crypto/virtio/virtio_crypto_common.h b/drivers/crypto/virtio/virtio_crypto_common.h
index 05eca12e..76d49ec 100644
--- a/drivers/crypto/virtio/virtio_crypto_common.h
+++ b/drivers/crypto/virtio/virtio_crypto_common.h
@@ -116,7 +116,12 @@  int virtcrypto_dev_in_use(struct virtio_crypto *vcrypto_dev);
 int virtcrypto_dev_get(struct virtio_crypto *vcrypto_dev);
 void virtcrypto_dev_put(struct virtio_crypto *vcrypto_dev);
 int virtcrypto_dev_started(struct virtio_crypto *vcrypto_dev);
-struct virtio_crypto *virtcrypto_get_dev_node(int node);
+bool virtcrypto_algo_is_supported(struct virtio_crypto *vcrypto_dev,
+				  uint32_t service,
+				  uint32_t algo);
+struct virtio_crypto *virtcrypto_get_dev_node(int node,
+					      uint32_t service,
+					      uint32_t algo);
 int virtcrypto_dev_start(struct virtio_crypto *vcrypto);
 void virtcrypto_dev_stop(struct virtio_crypto *vcrypto);
 int virtio_crypto_ablkcipher_crypt_req(
@@ -136,7 +141,7 @@  static inline int virtio_crypto_get_current_node(void)
 	return node;
 }
 
-int virtio_crypto_algs_register(void);
-void virtio_crypto_algs_unregister(void);
+int virtio_crypto_algs_register(struct virtio_crypto *vcrypto);
+void virtio_crypto_algs_unregister(struct virtio_crypto *vcrypto);
 
 #endif /* _VIRTIO_CRYPTO_COMMON_H */
diff --git a/drivers/crypto/virtio/virtio_crypto_mgr.c b/drivers/crypto/virtio/virtio_crypto_mgr.c
index a69ff71..d70de3a 100644
--- a/drivers/crypto/virtio/virtio_crypto_mgr.c
+++ b/drivers/crypto/virtio/virtio_crypto_mgr.c
@@ -181,14 +181,20 @@  int virtcrypto_dev_started(struct virtio_crypto *vcrypto_dev)
 /*
  * virtcrypto_get_dev_node() - Get vcrypto_dev on the node.
  * @node:  Node id the driver works.
+ * @service: Crypto service that needs to be supported by the
+ *	      dev
+ * @algo: The algorithm number that needs to be supported by the
+ *	  dev
  *
- * Function returns the virtio crypto device used fewest on the node.
+ * Function returns the virtio crypto device used fewest on the node,
+ * and supports the given crypto service and algorithm.
  *
  * To be used by virtio crypto device specific drivers.
  *
  * Return: pointer to vcrypto_dev or NULL if not found.
  */
-struct virtio_crypto *virtcrypto_get_dev_node(int node)
+struct virtio_crypto *virtcrypto_get_dev_node(int node, uint32_t service,
+					      uint32_t algo)
 {
 	struct virtio_crypto *vcrypto_dev = NULL, *tmp_dev;
 	unsigned long best = ~0;
@@ -199,7 +205,8 @@  struct virtio_crypto *virtcrypto_get_dev_node(int node)
 
 		if ((node == dev_to_node(&tmp_dev->vdev->dev) ||
 		     dev_to_node(&tmp_dev->vdev->dev) < 0) &&
-		    virtcrypto_dev_started(tmp_dev)) {
+		    virtcrypto_dev_started(tmp_dev) &&
+		    virtcrypto_algo_is_supported(tmp_dev, service, algo)) {
 			ctr = atomic_read(&tmp_dev->ref_count);
 			if (best > ctr) {
 				vcrypto_dev = tmp_dev;
@@ -214,7 +221,9 @@  struct virtio_crypto *virtcrypto_get_dev_node(int node)
 		/* Get any started device */
 		list_for_each_entry(tmp_dev,
 				virtcrypto_devmgr_get_head(), list) {
-			if (virtcrypto_dev_started(tmp_dev)) {
+			if (virtcrypto_dev_started(tmp_dev) &&
+			    virtcrypto_algo_is_supported(tmp_dev,
+			    service, algo)) {
 				vcrypto_dev = tmp_dev;
 				break;
 			}
@@ -240,7 +249,7 @@  struct virtio_crypto *virtcrypto_get_dev_node(int node)
  */
 int virtcrypto_dev_start(struct virtio_crypto *vcrypto)
 {
-	if (virtio_crypto_algs_register()) {
+	if (virtio_crypto_algs_register(vcrypto)) {
 		pr_err("virtio_crypto: Failed to register crypto algs\n");
 		return -EFAULT;
 	}
@@ -260,5 +269,65 @@  int virtcrypto_dev_start(struct virtio_crypto *vcrypto)
  */
 void virtcrypto_dev_stop(struct virtio_crypto *vcrypto)
 {
-	virtio_crypto_algs_unregister();
+	virtio_crypto_algs_unregister(vcrypto);
+}
+
+/*
+ * vcrypto_algo_is_supported()
+ * @vcrypto: Pointer to virtio crypto device.
+ * @service: The bit number for service validate.
+ *	      See VIRTIO_CRYPTO_SERVICE_*
+ * @algo : The bit number for the algorithm to validate.
+ *
+ *
+ * Validate if the virtio crypto device supports a service and
+ * algo.
+ *
+ * Return true if device supports a service and algo.
+ */
+
+bool virtcrypto_algo_is_supported(struct virtio_crypto *vcrypto,
+				  uint32_t service,
+				  uint32_t algo)
+{
+	uint32_t service_mask = 1u << service;
+	uint32_t algo_mask = 0;
+	bool low = true;
+
+	if (algo > 31) {
+		algo -= 32;
+		low = false;
+	}
+
+	if (!(vcrypto->crypto_services & service_mask))
+		return false;
+
+	switch (service) {
+	case VIRTIO_CRYPTO_SERVICE_CIPHER:
+		if (low)
+			algo_mask = vcrypto->cipher_algo_l;
+		else
+			algo_mask = vcrypto->cipher_algo_h;
+		break;
+
+	case VIRTIO_CRYPTO_SERVICE_HASH:
+		algo_mask = vcrypto->hash_algo;
+		break;
+
+	case VIRTIO_CRYPTO_SERVICE_MAC:
+		if (low)
+			algo_mask = vcrypto->mac_algo_l;
+		else
+			algo_mask = vcrypto->mac_algo_h;
+		break;
+
+	case VIRTIO_CRYPTO_SERVICE_AEAD:
+		algo_mask = vcrypto->aead_algo;
+		break;
+	}
+
+	if (!(algo_mask & (1u << algo)))
+		return false;
+
+	return true;
 }