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[v21,1/2] virtio-crypto: Add virtio crypto device specification

Message ID 1509951193-25256-2-git-send-email-longpeng2@huawei.com
State New
Headers show
Series virtio-crypto: virtio crypto device specification | expand

Commit Message

Longpeng (Mike, Cloud Infrastructure Service Product Dept.) Nov. 6, 2017, 6:53 a.m. UTC 
From: Gonglei <arei.gonglei@huawei.com>

The virtio crypto device is a virtual crypto device (ie. hardware
crypto accelerator card). Currently, the virtio crypto device provides
the following crypto services: CIPHER, MAC, HASH, and AEAD.

In this patch, CIPHER, MAC, HASH, AEAD services are introduced.

VIRTIO-153

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
---
 acknowledgements.tex |    3 +
 content.tex          |    2 +
 virtio-crypto.tex    | 1426 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1431 insertions(+)
 create mode 100644 virtio-crypto.tex

Comments

Halil Pasic Nov. 8, 2017, 6:35 p.m. UTC | #1 
[..]

On 11/06/2017 07:53 AM, Longpeng(Mike) wrote:
> +\subsection{Device Operation}\label{sec:Device Types / Crypto Device / Device Operation}
> +
> +The operation of a virtio crypto device is driven by requests placed on the virtqueues.
> +Requests consist of a queue-type specific header (specifying among others the operation)
> +and an operation specific payload. The payload is generally composed of operation
> +parameters, output data, and input data. Operation parameters are crypto-service-specific
> +parameters, output data is the data that should be utilized in operations, and input
> +data is equal to "operation result + result data".
> +
> +If VIRTIO_CRYPTO_F_MUX_MODE is negotioated the device may support both session mode

s/negotioated/negotiated/

> +(See \ref{sec:Device Types / Crypto Device / Device Operation / Control Virtqueue / Session operation})
> +and stateless mode operation requests.
> +In stateless mode all operation parameters are supplied as a part of each request,
> +while in session mode, some or all operation parameters are managed within the
> +session. Stateless mode is guarded by feature bits 0-4 on a service level. If
> +stateless mode is negotiated for a service, the service is available both in
> +session and stateless mode; otherwise it's only available in session mode.
> +
> +\subsubsection{Operation Status}\label{sec:Device Types / Crypto Device / Device Operation / Operation status}
> +The device MUST return a status code as part of the operation (both session
> +operation and service operation) result. The valid operation status as follows:
> +
> +\begin{lstlisting}
> +enum VIRTIO_CRYPTO_STATUS {
> +    VIRTIO_CRYPTO_OK = 0,
> +    VIRTIO_CRYPTO_ERR = 1,
> +    VIRTIO_CRYPTO_BADMSG = 2,
> +    VIRTIO_CRYPTO_NOTSUPP = 3,
> +    VIRTIO_CRYPTO_INVSESS = 4,
> +    VIRTIO_CRYPTO_NOSPC = 5,
> +    VIRTIO_CRYPTO_MAX
> +};
> +\end{lstlisting}
> +
> +\begin{itemize*}
> +\item VIRTIO_CRYPTO_OK: success.
> +\item VIRTIO_CRYPTO_BADMSG: authentication failed (only when AEAD decryption).
> +\item VIRTIO_CRYPTO_NOTSUPP: operation or algorithm is unsupported.
> +\item VIRTIO_CRYPTO_INVSESS: invalid session ID when executing crypto operations.
> +\item VIRTIO_CRYPTO_NOSPC: no free session ID (only when the VIRTIO_CRYPTO_F_MUX_MODE
> +    feature bit is negotiated).
> +\item VIRTIO_CRYPTO_ERR: any failure not mentioned above occurs.
> +\end{itemize*}
> +
> +\subsubsection{Control Virtqueue}\label{sec:Device Types / Crypto Device / Device Operation / Control Virtqueue}
> +
> +The driver uses the control virtqueue to send control commands to the
> +device, such as session operations (See \ref{sec:Device Types / Crypto Device / Device Operation / Control Virtqueue / Session operation}).
> +
> +The header for controlq is of the following form:
> +\begin{lstlisting}
> +#define VIRTIO_CRYPTO_OPCODE(service, op)   (((service) << 8) | (op))
> +
> +struct virtio_crypto_ctrl_header {
> +#define VIRTIO_CRYPTO_CIPHER_CREATE_SESSION \
> +       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_CIPHER, 0x02)
> +#define VIRTIO_CRYPTO_CIPHER_DESTROY_SESSION \
> +       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_CIPHER, 0x03)
> +#define VIRTIO_CRYPTO_HASH_CREATE_SESSION \
> +       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_HASH, 0x02)
> +#define VIRTIO_CRYPTO_HASH_DESTROY_SESSION \
> +       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_HASH, 0x03)
> +#define VIRTIO_CRYPTO_MAC_CREATE_SESSION \
> +       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_MAC, 0x02)
> +#define VIRTIO_CRYPTO_MAC_DESTROY_SESSION \
> +       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_MAC, 0x03)
> +#define VIRTIO_CRYPTO_AEAD_CREATE_SESSION \
> +       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_AEAD, 0x02)
> +#define VIRTIO_CRYPTO_AEAD_DESTROY_SESSION \
> +       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_AEAD, 0x03)
> +    le32 opcode;
> +    /* algo should be service-specific algorithms */
> +    le32 algo;
> +    le32 flag;
> +    le32 reserved;
> +};
> +\end{lstlisting}
> +
> +The controlq request is composed of two parts:
> +\begin{lstlisting}
> +struct virtio_crypto_op_ctrl_req {
> +    struct virtio_crypto_ctrl_header header;
> +
> +    /* additional paramenter */
> +    u8 additional_para[addl_para_len];

What does additional paramenter mean? Even if I s/paramenter/parameter
id doesn't sit well. To me and in this context additional is kind
of like optional: because each member of a struct is trivially additional
in respect to the previous members, and there is no point in pointing
out additional. I would much rather go with something like:
u8 op_specific[]

I also don't find the addl_para_len used anywhere. Then IMHO we don't
need to introduce a name.

> +};
> +\end{lstlisting}
> +
> +The first is a general header (see above). And the second one, additional
> +paramenter, contains an crypto-service-specific structure, which could be one

s/paramenter/parameter

It's actually opcode specific, or? Or is there a destroy service?

> +of the following types:
> +\begin{itemize*}
> +\item struct virtio_crypto_sym_create_session_req
> +\item struct virtio_crypto_hash_create_session_req
> +\item struct virtio_crypto_mac_create_session_req
> +\item struct virtio_crypto_aead_create_session_req
> +\item virtio_crypto_destroy_session_req
> +\end{itemize*}
> +
> +The size of the additional paramenter depends on the VIRTIO_CRYPTO_F_MUX_MODE

s/paramenter/parameter

> +feature bit:
> +\item If the VIRTIO_CRYPTO_F_MUX_MODE feature bit is NOT negotiated, the
> +    size of additional paramenter is fixed to 56 bytes, the data of the unused

s/paramenter/parameter

> +    part (if has) will be ingored.

s/ingored/ignored


> +\item If the VIRTIO_CRYPTO_F_MUX_MODE feature bit is negotiated, the size of
> +    additional paramenter is flexible, which is the same as the crypto-service-specific

s/paramenter/parameter

> +    structure used.
> +
> +\paragraph{Session operation}\label{sec:Device Types / Crypto Device / Device Operation / Control Virtqueue / Session operation}
> +
> +The session is a handle which describes the cryptographic parameters to be
> +applied to a number of buffers.
> +
> +The following structure stores the result of session creation set by the device:
> +
> +\begin{lstlisting}
> +struct virtio_crypto_session_input {
> +    /* Device-writable part */
> +    le64 session_id;
> +    le32 status;
> +    le32 padding;
> +};
> +\end{lstlisting}
> +
> +A request to destroy a session includes the following information:
> +
> +\begin{lstlisting}
> +struct virtio_crypto_destroy_session_req {
> +    /* Device-readable part */
> +    le64  session_id;
> +    /* Device-writable part */
> +    le32  status;
> +    le32  padding;
> +};
> +\end{lstlisting}
> +
> +\subparagraph{Session operation: HASH session}\label{sec:Device Types / Crypto Device / Device
> +Operation / Control Virtqueue / Session operation / Session operation: HASH session}
> +

Let me skip to the one actually implemented.

> +HASH session requests are as follows:
> +
> +\begin{lstlisting}
> +struct virtio_crypto_hash_session_para {
> +    /* See VIRTIO_CRYPTO_HASH_* above */
> +    le32 algo;
> +    /* hash result length */
> +    le32 hash_result_len;
> +};
> +struct virtio_crypto_hash_create_session_req {
> +    /* Device-readable part */
> +    struct virtio_crypto_hash_session_para para;
> +    /* Device-writable part */
> +    struct virtio_crypto_session_input input;
> +};
> +\end{lstlisting}
> +
> +The information required by HASH session creation is stored in the
> +virtio_crypto_hash_create_session_req structure, including the hash
> +parameters stored in \field{para}. \field{input} stores the result of
> +this operation.
> +
> +\subparagraph{Session operation: MAC session}\label{sec:Device Types / Crypto Device / Device
> +Operation / Control Virtqueue / Session operation / Session operation: MAC session}
> +
> +MAC session requests are as follows:
> +
> +\begin{lstlisting}
> +struct virtio_crypto_mac_session_para {
> +    /* See VIRTIO_CRYPTO_MAC_* above */
> +    le32 algo;
> +    /* hash result length */
> +    le32 hash_result_len;
> +    /* length of authenticated key */
> +    le32 auth_key_len;
> +    le32 padding;
> +};
> +
> +struct virtio_crypto_mac_create_session_req {
> +    /* Device-readable part */
> +    struct virtio_crypto_mac_session_para para;
> +    /* The authenticated key */
> +    u8 auth_key[auth_key_len];
> +
> +    /* Device-writable part */
> +    struct virtio_crypto_session_input input;
> +};
> +\end{lstlisting}
> +
> +The information required by MAC session creation is stored in the
> +virtio_crypto_mac_create_session_req structure, including the mac
> +parameters stored in \field{para} and the authenticated key in \field{auth_key}.
> +\field{input} stores the result of this operation.
> +
> +\subparagraph{Session operation: Symmetric algorithms session}\label{sec:Device Types / Crypto Device / Device
> +Operation / Control Virtqueue / Session operation / Session operation: Symmetric algorithms session}

Here we are!

> +
> +The request of symmetric session includes two parts, CIPHER algorithms
> +and chain algorithms (chaining CIPHER and HASH/MAC).

This sounds like concatenation and not either-or.
> +
> +CIPHER session requests are as follows:
> +
> +\begin{lstlisting}
> +struct virtio_crypto_cipher_session_para {
> +    /* See VIRTIO_CRYPTO_CIPHER* above */
> +    le32 algo;
> +    /* length of key */
> +    le32 keylen;
> +#define VIRTIO_CRYPTO_OP_ENCRYPT  1
> +#define VIRTIO_CRYPTO_OP_DECRYPT  2
> +    /* encryption or decryption */
> +    le32 op;
> +    le32 padding;
> +};
> +
> +struct virtio_crypto_cipher_session_req {
> +    /* Device-readable part */
> +    struct virtio_crypto_cipher_session_para para;
> +    /* The cipher key */
> +    u8 cipher_key[keylen];
> +

Is there a limit to the size of chiper_key. I don't see one in your
kernel code. OTOH given that virtio_crypto_sym_create_session_req
is one flavor of virtio_crypto_op_ctrl_req.additional_para and that
the later is 56 bytes in case no mux mode is supported, I think
there must be a limit to the size of cipher_key!

Please explain!

Looking at the kernel code again, it seems to me that chiper_key
starts at offset 72 == sizeof(struct virtio_crypto_op_ctrl_req)
where struct virtio_crypto_op_ctrl_req is defined in
include/uapi/linux/virtio_crypto.h. That would mean that this
guy is *not a part of* virtio_crypto_op_ctrl_req but comes
after it and is of variable size.

> +    /* Device-writable part */


Now I'm interested on what 'offset' does the device writable
part start. 

Of course technically we don't need to know this, because we
have a device-read-only or device-write-only indication on each
descriptor. So virtio_crypto_session_input starts with the first
device write only descriptor.

> +    struct virtio_crypto_session_input input;
> +};
> +\end{lstlisting}
> +
> +Algorithm chaining requests are as follows:
> +
> +\begin{lstlisting}
> +struct virtio_crypto_alg_chain_session_para {
> +#define VIRTIO_CRYPTO_SYM_ALG_CHAIN_ORDER_HASH_THEN_CIPHER  1
> +#define VIRTIO_CRYPTO_SYM_ALG_CHAIN_ORDER_CIPHER_THEN_HASH  2
> +    le32 alg_chain_order;
> +/* Plain hash */
> +#define VIRTIO_CRYPTO_SYM_HASH_MODE_PLAIN    1
> +/* Authenticated hash (mac) */
> +#define VIRTIO_CRYPTO_SYM_HASH_MODE_AUTH     2
> +/* Nested hash */
> +#define VIRTIO_CRYPTO_SYM_HASH_MODE_NESTED   3
> +    le32 hash_mode;
> +    struct virtio_crypto_cipher_session_para cipher_param;
> +
> +    /*
> +     * The additional_para is fixed to 16 bytes in length, it
> +     * contains a virtio_crypto_hash_session_para structure or
> +     * a virtio_crypto_mac_session_para structure and the data
> +     * of unused part (if has) will be ingored.
> +     */
> +#define VIRTIO_CRYPTO_ALG_CHAIN_SESS_PARA_SIZE  16
> +    u8 additional_para[VIRTIO_CRYPTO_ALG_CHAIN_SESS_PARA_SIZE];
> +
> +    /* length of the additional authenticated data (AAD) in bytes */
> +    le32 aad_len;
> +    le32 padding;
> +};
> +
> +struct virtio_crypto_alg_chain_session_req {
> +    /* Device-readable part */
> +    struct virtio_crypto_alg_chain_session_para para;
> +    /* The cipher key */
> +    u8 cipher_key[keylen];
> +    /* The authenticated key */
> +    u8 auth_key[auth_key_len];
> +
> +    /* Device-writable part */
> +    struct virtio_crypto_session_input input;
> +};
> +\end{lstlisting}
> +
> +Symmetric algorithm requests are as follows:
> +
> +\begin{lstlisting}
> +struct virtio_crypto_sym_create_session_req {
> +    /*
> +     * The additional_para is fixed to 48 bytes in length, it
> +     * contains a virtio_crypto_cipher_session_req structure or
> +     * a virtio_crypto_alg_chain_session_req structure and the
> +     * data of unused part (if has) will be ingored.
> +     */
> +#define VIRTIO_CRYPTO_SYM_CREATE_SESS_PARA_SIZE  48
> +    u8 additional_para[VIRTIO_CRYPTO_SYM_CREATE_SESS_PARA_SIZE];
> +
> +    /* Device-readable part */
> +
> +/* No operation */
> +#define VIRTIO_CRYPTO_SYM_OP_NONE  0
> +/* Cipher only operation on the data */
> +#define VIRTIO_CRYPTO_SYM_OP_CIPHER  1
> +/* Chain any cipher with any hash or mac operation. The order
> +   depends on the value of alg_chain_order param */
> +#define VIRTIO_CRYPTO_SYM_OP_ALGORITHM_CHAINING  2
> +    le32 op_type;
> +    le32 padding;
> +};
> +\end{lstlisting}
> +
> +The information required by symmetric algorithms session creation is stored in the
> +virtio_crypto_sym_create_session_req structure, including the symmetric operation
> +type in \field{op_type} and the cipher parameters stored in \field{cipher} or the
> +algorithm chaining paramenters in \field{chain}.
> +
> +The driver can set the \field{op_type} field in struct virtio_crypto_sym_create_session_req
> +as follows: VIRTIO_CRYPTO_SYM_OP_NONE: no operation; VIRTIO_CRYPTO_SYM_OP_CIPHER: Cipher only
> +operation on the data; VIRTIO_CRYPTO_SYM_OP_ALGORITHM_CHAINING: Chain any cipher with any hash
> +or mac operation.
> +

Based on the stuff written here, it ain't obvious to me at which offset does
the device writable part (that is virtio_crypto_session_input) start.

From your kernel code, it seems to me that it starts at offset 72 + keylen.


To sum it up I'm awfully dissatisfied. Maybe I made some mistake somewhere,
and that's why things don't make sense.

I would really appreciate somebody else having a look, and telling:
is it possible to figure out the message formats and create an inter-operable
implementation based on this text (and without looking at the Linux/QEMU code)?


> +\subparagraph{Session operation: AEAD session}\label{sec:Device Types / Crypto Device / Device
> +Operation / Control Virtqueue / Session operation / Session operation: AEAD session}

Further review does not make sense at the moment. If it's just my train of thought
that got derailed, please put it back on the rails first.

Regards,
Halil

[..]
Gonglei (Arei) Nov. 13, 2017, 7:17 a.m. UTC | #2 
Hi,

>

> > +The controlq request is composed of two parts:

> > +\begin{lstlisting}

> > +struct virtio_crypto_op_ctrl_req {

> > +    struct virtio_crypto_ctrl_header header;

> > +

> > +    /* additional paramenter */

> > +    u8 additional_para[addl_para_len];

> 

> What does additional paramenter mean? Even if I s/paramenter/parameter

> id doesn't sit well. To me and in this context additional is kind

> of like optional: because each member of a struct is trivially additional

> in respect to the previous members, and there is no point in pointing

> out additional. I would much rather go with something like:

> u8 op_specific[]

> 

> I also don't find the addl_para_len used anywhere. Then IMHO we don't

> need to introduce a name.

> 


I'd like to say that the additional_para[addl_para_len] is just a placeholder,
which is explained by the below content. I'm fine with op_specific[] too.

> > +};

> > +\end{lstlisting}

> > +

> > +The first is a general header (see above). And the second one, additional

> > +paramenter, contains an crypto-service-specific structure, which could be

> one

> 

> s/paramenter/parameter

> 

> It's actually opcode specific, or? Or is there a destroy service?

> 

We can choose the specific request (structure) as the *op_specific* according to opcode.

> > +of the following types:

> > +\begin{itemize*}

> > +\item struct virtio_crypto_sym_create_session_req

> > +\item struct virtio_crypto_hash_create_session_req

> > +\item struct virtio_crypto_mac_create_session_req

> > +\item struct virtio_crypto_aead_create_session_req

> > +\item virtio_crypto_destroy_session_req

> > +\end{itemize*}

> > +

> > +The size of the additional paramenter depends on the

> VIRTIO_CRYPTO_F_MUX_MODE

> 

> s/paramenter/parameter

> 

> > +feature bit:

> > +\item If the VIRTIO_CRYPTO_F_MUX_MODE feature bit is NOT negotiated,

> the

> > +    size of additional paramenter is fixed to 56 bytes, the data of the

> unused

> 

> s/paramenter/parameter

> 

> > +    part (if has) will be ingored.

> 

> s/ingored/ignored

> 

> 

> > +\item If the VIRTIO_CRYPTO_F_MUX_MODE feature bit is negotiated, the

> size of

> > +    additional paramenter is flexible, which is the same as the

> crypto-service-specific

> 

> s/paramenter/parameter

> 

> > +    structure used.

> > +

> > +\paragraph{Session operation}\label{sec:Device Types / Crypto Device /

> Device Operation / Control Virtqueue / Session operation}

> > +

> > +The session is a handle which describes the cryptographic parameters to be

> > +applied to a number of buffers.

> > +

> > +The following structure stores the result of session creation set by the

> device:

> > +

> > +\begin{lstlisting}

> > +struct virtio_crypto_session_input {

> > +    /* Device-writable part */

> > +    le64 session_id;

> > +    le32 status;

> > +    le32 padding;

> > +};

> > +\end{lstlisting}

> > +

> > +A request to destroy a session includes the following information:

> > +

> > +\begin{lstlisting}

> > +struct virtio_crypto_destroy_session_req {

> > +    /* Device-readable part */

> > +    le64  session_id;

> > +    /* Device-writable part */

> > +    le32  status;

> > +    le32  padding;

> > +};

> > +\end{lstlisting}

> > +

> > +\subparagraph{Session operation: HASH session}\label{sec:Device Types /

> Crypto Device / Device

> > +Operation / Control Virtqueue / Session operation / Session operation: HASH

> session}

> > +

> 

> Let me skip to the one actually implemented.

> 

> > +

> > +The request of symmetric session includes two parts, CIPHER algorithms

> > +and chain algorithms (chaining CIPHER and HASH/MAC).

> 

> This sounds like concatenation and not either-or.

> > +

> > +CIPHER session requests are as follows:

> > +

> > +\begin{lstlisting}

> > +struct virtio_crypto_cipher_session_para {

> > +    /* See VIRTIO_CRYPTO_CIPHER* above */

> > +    le32 algo;

> > +    /* length of key */

> > +    le32 keylen;

> > +#define VIRTIO_CRYPTO_OP_ENCRYPT  1

> > +#define VIRTIO_CRYPTO_OP_DECRYPT  2

> > +    /* encryption or decryption */

> > +    le32 op;

> > +    le32 padding;

> > +};

> > +

> > +struct virtio_crypto_cipher_session_req {

> > +    /* Device-readable part */

> > +    struct virtio_crypto_cipher_session_para para;

> > +    /* The cipher key */

> > +    u8 cipher_key[keylen];

> > +

> 

> Is there a limit to the size of chiper_key. I don't see one in your

> kernel code. OTOH given that virtio_crypto_sym_create_session_req

> is one flavor of virtio_crypto_op_ctrl_req.additional_para and that

> the later is 56 bytes in case no mux mode is supported, I think

> there must be a limit to the size of cipher_key!

> 

Of course the size of cipher_key is limited, firstly the max length is defined
in virtio crypto's configuration, see

struct virtio_crypto_config {
  ... ...
    /* Maximum length of cipher key */
    uint32_t max_cipher_key_len;
  ... ...
};

Secondly the real cipher_key size for a specific request, is in struct virtio_crypto_cipher_session_para,

struct virtio_crypto_cipher_session_para {
   ... ...
    /* length of key */
    le32 keylen;
   ... ...
};

That means a size of cipher_key is variable, which is assigned in each request.

> Please explain!

> 

> Looking at the kernel code again, it seems to me that chiper_key

> starts at offset 72 == sizeof(struct virtio_crypto_op_ctrl_req)

> where struct virtio_crypto_op_ctrl_req is defined in

> include/uapi/linux/virtio_crypto.h. That would mean that this

> guy is *not a part of* virtio_crypto_op_ctrl_req but comes

> after it and is of variable size.

> 

> > +    /* Device-writable part */

> 

> 

> Now I'm interested on what 'offset' does the device writable

> part start.

> 

> Of course technically we don't need to know this, because we

> have a device-read-only or device-write-only indication on each

> descriptor. So virtio_crypto_session_input starts with the first

> device write only descriptor.

> 

You are right. We definitely don't need to know this. Pls see Qemu code:
virtio_crypto_handle_request():

    /* We always touch the last byte, so just see how big in_iov is. */
    request->in_len = iov_size(in_iov, in_num);
    request->in = (void *)in_iov[in_num - 1].iov_base
              + in_iov[in_num - 1].iov_len
              - sizeof(struct virtio_crypto_inhdr);
    iov_discard_back(in_iov, &in_num, sizeof(struct virtio_crypto_inhdr));

The above in_iov means device-writable iov.

> > +    struct virtio_crypto_session_input input;

> > +};

> > +\end{lstlisting}

> > +

> > +Algorithm chaining requests are as follows:

> > +

> > +\begin{lstlisting}

> > +struct virtio_crypto_alg_chain_session_para {

> > +#define VIRTIO_CRYPTO_SYM_ALG_CHAIN_ORDER_HASH_THEN_CIPHER

> 1

> > +#define VIRTIO_CRYPTO_SYM_ALG_CHAIN_ORDER_CIPHER_THEN_HASH

> 2


[skip]

> > +The driver can set the \field{op_type} field in struct

> virtio_crypto_sym_create_session_req

> > +as follows: VIRTIO_CRYPTO_SYM_OP_NONE: no operation;

> VIRTIO_CRYPTO_SYM_OP_CIPHER: Cipher only

> > +operation on the data; VIRTIO_CRYPTO_SYM_OP_ALGORITHM_CHAINING:

> Chain any cipher with any hash

> > +or mac operation.

> > +

> 

> Based on the stuff written here, it ain't obvious to me at which offset does

> the device writable part (that is virtio_crypto_session_input) start.

> 


Why do we need to know the offset? IMO we only need to follow the spec arrangement to 
fill the specific request packet will not be a problem, such as general header + out_data + in_data. 
Driver first complete read-only part, then the writable part. The device then parses the 
request packet this way. Why do we need to write this offset in the spec?

> From your kernel code, it seems to me that it starts at offset 72 + keylen.

> 

> 

> To sum it up I'm awfully dissatisfied. Maybe I made some mistake somewhere,

> and that's why things don't make sense.

> 

> I would really appreciate somebody else having a look, and telling:

> is it possible to figure out the message formats and create an inter-operable

> implementation based on this text (and without looking at the Linux/QEMU

> code)?

> 

Yes, we need some other comments about this.

Thanks,
-Gonglei
> 

> > +\subparagraph{Session operation: AEAD session}\label{sec:Device Types /

> Crypto Device / Device

> > +Operation / Control Virtqueue / Session operation / Session operation: AEAD

> session}

> 

> Further review does not make sense at the moment. If it's just my train of

> thought

> that got derailed, please put it back on the rails first.

> 

> Regards,

> Halil

> 

> [..]

> 

> 

> ---------------------------------------------------------------------

> To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org

> For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org
Halil Pasic Nov. 13, 2017, 1:08 p.m. UTC | #3 
On 11/13/2017 08:17 AM, Gonglei (Arei) wrote:
>>> +struct virtio_crypto_cipher_session_req {
>>> +    /* Device-readable part */
>>> +    struct virtio_crypto_cipher_session_para para;
>>> +    /* The cipher key */
>>> +    u8 cipher_key[keylen];
>>> +
>> Is there a limit to the size of chiper_key. I don't see one in your
>> kernel code. OTOH given that virtio_crypto_sym_create_session_req
>> is one flavor of virtio_crypto_op_ctrl_req.additional_para and that
>> the later is 56 bytes in case no mux mode is supported, I think
>> there must be a limit to the size of cipher_key!
>>
> Of course the size of cipher_key is limited, firstly the max length is defined
> in virtio crypto's configuration, see
> 
> struct virtio_crypto_config {
>   ... ...
>     /* Maximum length of cipher key */
>     uint32_t max_cipher_key_len;
>   ... ...
> };
> 

So for the current qemu implementation it's 64 bytes.

> Secondly the real cipher_key size for a specific request, is in struct virtio_crypto_cipher_session_para,
> 
> struct virtio_crypto_cipher_session_para {
>    ... ...
>     /* length of key */
>     le32 keylen;
>    ... ...
> };
> 
> That means a size of cipher_key is variable, which is assigned in each request.

Of course I understood that. There are two problems I was trying
to point out, and you ignored both.

1. The more important one I was explicit about. Sadly you ignored
that part of my mail. I will mark it as *Problem 1* down below.

2. If there is a limit to the size, then there should be a driver
normative statement ("Driver Requirements") that states this limit
MUST be respected. I didn't find this statement.
> 
>> Please explain!
>>
>> Looking at the kernel code again, it seems to me that chiper_key
>> starts at offset 72 == sizeof(struct virtio_crypto_op_ctrl_req)
>> where struct virtio_crypto_op_ctrl_req is defined in
>> include/uapi/linux/virtio_crypto.h. That would mean that this
>> guy is *not a part of* virtio_crypto_op_ctrl_req but comes
>> after it and is of variable size.

*Problem 1*

Now consider the part where the whole request is described

"""
+The controlq request is composed of two parts:
+\begin{lstlisting}
+struct virtio_crypto_op_ctrl_req {
+    struct virtio_crypto_ctrl_header header;
+
+    /* additional paramenter */
+    u8 additional_para[addl_para_len];
+};
+\end{lstlisting}
+
+The first is a general header (see above). And the second one, additional
+paramenter, contains an crypto-service-specific structure, which could be one
+of the following types:
+\begin{itemize*}
+\item struct virtio_crypto_sym_create_session_req
+\item struct virtio_crypto_hash_create_session_req
+\item struct virtio_crypto_mac_create_session_req
+\item struct virtio_crypto_aead_create_session_req
+\item virtio_crypto_destroy_session_req
+\end{itemize*}
+
+The size of the additional paramenter depends on the VIRTIO_CRYPTO_F_MUX_MODE
+feature bit:
+\item If the VIRTIO_CRYPTO_F_MUX_MODE feature bit is NOT negotiated, the
+    size of additional paramenter is fixed to 56 bytes, the data of the unused
+    part (if has) will be ingored.
+\item If the VIRTIO_CRYPTO_F_MUX_MODE feature bit is negotiated, the size of
+    additional paramenter is flexible, which is the same as the crypto-service-specific
+    structure used.
"""

There it's said that the whole request is header + additional_para and that
if VIRTIO_CRYPTO_F_MUX_MODE feature bit is NOT negotiated additional para
is 56 bytes. Let's assume the key is part of the additional parameter.
But you can't put 64 bytes into 56 bytes. So as I say above
*the key is not part of virtio_crypto_op_ctrl_req* neiter as described
in this spec nor as defined in uapi/linux/virtio_crypto.h. That means
the communication protocol description (more precisely the message format
description) in the spec is broken. QED

In my opinion this is a big issue.


>>
>>> +    /* Device-writable part */
>>
>> Now I'm interested on what 'offset' does the device writable
>> part start.
>>
>> Of course technically we don't need to know this, because we
>> have a device-read-only or device-write-only indication on each
>> descriptor. So virtio_crypto_session_input starts with the first
>> device write only descriptor.
>>
> You are right. We definitely don't need to know this. Pls see Qemu code:
> virtio_crypto_handle_request():
> 
>     /* We always touch the last byte, so just see how big in_iov is. */
>     request->in_len = iov_size(in_iov, in_num);
>     request->in = (void *)in_iov[in_num - 1].iov_base
>               + in_iov[in_num - 1].iov_len
>               - sizeof(struct virtio_crypto_inhdr);
>     iov_discard_back(in_iov, &in_num, sizeof(struct virtio_crypto_inhdr));
> 
> The above in_iov means device-writable iov.
> 

I've seen that code. Thanks.

>>> +    struct virtio_crypto_session_input input;
>>> +};
>>> +\end{lstlisting}
>>> +
>>> +Algorithm chaining requests are as follows:
>>> +
>>> +\begin{lstlisting}
>>> +struct virtio_crypto_alg_chain_session_para {
>>> +#define VIRTIO_CRYPTO_SYM_ALG_CHAIN_ORDER_HASH_THEN_CIPHER
>> 1
>>> +#define VIRTIO_CRYPTO_SYM_ALG_CHAIN_ORDER_CIPHER_THEN_HASH
>> 2
> [skip]
> 
>>> +The driver can set the \field{op_type} field in struct
>> virtio_crypto_sym_create_session_req
>>> +as follows: VIRTIO_CRYPTO_SYM_OP_NONE: no operation;
>> VIRTIO_CRYPTO_SYM_OP_CIPHER: Cipher only
>>> +operation on the data; VIRTIO_CRYPTO_SYM_OP_ALGORITHM_CHAINING:
>> Chain any cipher with any hash
>>> +or mac operation.
>>> +
>> Based on the stuff written here, it ain't obvious to me at which offset does
>> the device writable part (that is virtio_crypto_session_input) start.
>>
> Why do we need to know the offset? IMO we only need to follow the spec arrangement to 
> fill the specific request packet will not be a problem, such as general header + out_data + in_data. 
> Driver first complete read-only part, then the writable part. The device then parses the 
> request packet this way. Why do we need to write this offset in the spec?
> 

We actually don't. That is just what I've said a couple of lines before.
But we do need to know at which offset the key is (or any other piece of
information within the device readable and the device writable part).

Maybe it was not smart from me to ask this question.

I understood this specification as if it were trying to describe a message
format as structs, which are basically supposed to define the offset of the
individual fields. So for a guy trying to figure out the spec (because he
wants to implement it) asking himself at what offset a certain piece
of info is, is natural IMHO.

I don't think the placement of virtio_crypto_session_input is adequately
described. Please point me to the fragment if I've missed it. IMHO a
straightforward way to describe it would be that virtio_crypto_session_input
starts at the data address designated by the first device writable descriptor.

Regards,
Halil

>> From your kernel code, it seems to me that it starts at offset 72 + keylen.
>>
>>
>> To sum it up I'm awfully dissatisfied. Maybe I made some mistake somewhere,
>> and that's why things don't make sense.
>>
>> I would really appreciate somebody else having a look, and telling:
>> is it possible to figure out the message formats and create an inter-operable
>> implementation based on this text (and without looking at the Linux/QEMU
>> code)?
>>
> Yes, we need some other comments about this.
> > Thanks,
> -Gonglei
Gonglei (Arei) Nov. 13, 2017, 1:42 p.m. UTC | #4 
Hello Halil,

Thanks for your feedback. 

> 

> On 11/13/2017 08:17 AM, Gonglei (Arei) wrote:

> >>> +struct virtio_crypto_cipher_session_req {

> >>> +    /* Device-readable part */

> >>> +    struct virtio_crypto_cipher_session_para para;

> >>> +    /* The cipher key */

> >>> +    u8 cipher_key[keylen];

> >>> +

> >> Is there a limit to the size of chiper_key. I don't see one in your

> >> kernel code. OTOH given that virtio_crypto_sym_create_session_req

> >> is one flavor of virtio_crypto_op_ctrl_req.additional_para and that

> >> the later is 56 bytes in case no mux mode is supported, I think

> >> there must be a limit to the size of cipher_key!

> >>

> > Of course the size of cipher_key is limited, firstly the max length is defined

> > in virtio crypto's configuration, see

> >

> > struct virtio_crypto_config {

> >   ... ...

> >     /* Maximum length of cipher key */

> >     uint32_t max_cipher_key_len;

> >   ... ...

> > };

> >

> 

> So for the current qemu implementation it's 64 bytes.

> 

> > Secondly the real cipher_key size for a specific request, is in struct

> virtio_crypto_cipher_session_para,

> >

> > struct virtio_crypto_cipher_session_para {

> >    ... ...

> >     /* length of key */

> >     le32 keylen;

> >    ... ...

> > };

> >

> > That means a size of cipher_key is variable, which is assigned in each request.

> 

> Of course I understood that. There are two problems I was trying

> to point out, and you ignored both.

> 

> 1. The more important one I was explicit about. Sadly you ignored

> that part of my mail. I will mark it as *Problem 1* down below.

> 

> 2. If there is a limit to the size, then there should be a driver

> normative statement ("Driver Requirements") that states this limit

> MUST be respected. I didn't find this statement.


We can add it.

> >

> >> Please explain!

> >>

> >> Looking at the kernel code again, it seems to me that chiper_key

> >> starts at offset 72 == sizeof(struct virtio_crypto_op_ctrl_req)

> >> where struct virtio_crypto_op_ctrl_req is defined in

> >> include/uapi/linux/virtio_crypto.h. That would mean that this

> >> guy is *not a part of* virtio_crypto_op_ctrl_req but comes

> >> after it and is of variable size.

> 

> *Problem 1*

> 

> Now consider the part where the whole request is described

> 

> """

> +The controlq request is composed of two parts:

> +\begin{lstlisting}

> +struct virtio_crypto_op_ctrl_req {

> +    struct virtio_crypto_ctrl_header header;

> +

> +    /* additional paramenter */

> +    u8 additional_para[addl_para_len];

> +};

> +\end{lstlisting}

> +

> +The first is a general header (see above). And the second one, additional

> +paramenter, contains an crypto-service-specific structure, which could be one

> +of the following types:

> +\begin{itemize*}

> +\item struct virtio_crypto_sym_create_session_req

> +\item struct virtio_crypto_hash_create_session_req

> +\item struct virtio_crypto_mac_create_session_req

> +\item struct virtio_crypto_aead_create_session_req

> +\item virtio_crypto_destroy_session_req

> +\end{itemize*}

> +

> +The size of the additional paramenter depends on the

> VIRTIO_CRYPTO_F_MUX_MODE

> +feature bit:

> +\item If the VIRTIO_CRYPTO_F_MUX_MODE feature bit is NOT negotiated,

> the

> +    size of additional paramenter is fixed to 56 bytes, the data of the unused

> +    part (if has) will be ingored.

> +\item If the VIRTIO_CRYPTO_F_MUX_MODE feature bit is negotiated, the

> size of

> +    additional paramenter is flexible, which is the same as the

> crypto-service-specific

> +    structure used.

> """

> 

> There it's said that the whole request is header + additional_para and that

> if VIRTIO_CRYPTO_F_MUX_MODE feature bit is NOT negotiated additional

> para

> is 56 bytes. Let's assume the key is part of the additional parameter.

> But you can't put 64 bytes into 56 bytes. So as I say above

> *the key is not part of virtio_crypto_op_ctrl_req* neiter as described

> in this spec nor as defined in uapi/linux/virtio_crypto.h. That means

> the communication protocol description (more precisely the message format

> description) in the spec is broken. QED

> 

> In my opinion this is a big issue.

> 

OK, I get your point now. Sorry about that. :(

We should update the description about cipher_key and something like that.
The key is indeed not a part of virtio_crypto_op_ctrl_req in the realization, is
a separate entry in the descriptor table.

> 

> >>

> >>> +    /* Device-writable part */

> >>

> >> Now I'm interested on what 'offset' does the device writable

> >> part start.

> >>

> >> Of course technically we don't need to know this, because we

> >> have a device-read-only or device-write-only indication on each

> >> descriptor. So virtio_crypto_session_input starts with the first

> >> device write only descriptor.

> >>

> > You are right. We definitely don't need to know this. Pls see Qemu code:

> > virtio_crypto_handle_request():

> >

> >     /* We always touch the last byte, so just see how big in_iov is. */

> >     request->in_len = iov_size(in_iov, in_num);

> >     request->in = (void *)in_iov[in_num - 1].iov_base

> >               + in_iov[in_num - 1].iov_len

> >               - sizeof(struct virtio_crypto_inhdr);

> >     iov_discard_back(in_iov, &in_num, sizeof(struct virtio_crypto_inhdr));

> >

> > The above in_iov means device-writable iov.

> >

> 

> I've seen that code. Thanks.

> 

> >>> +    struct virtio_crypto_session_input input;

> >>> +};

> >>> +\end{lstlisting}

> >>> +

> >>> +Algorithm chaining requests are as follows:

> >>> +

> >>> +\begin{lstlisting}

> >>> +struct virtio_crypto_alg_chain_session_para {

> >>> +#define

> VIRTIO_CRYPTO_SYM_ALG_CHAIN_ORDER_HASH_THEN_CIPHER

> >> 1

> >>> +#define

> VIRTIO_CRYPTO_SYM_ALG_CHAIN_ORDER_CIPHER_THEN_HASH

> >> 2

> > [skip]

> >

> >>> +The driver can set the \field{op_type} field in struct

> >> virtio_crypto_sym_create_session_req

> >>> +as follows: VIRTIO_CRYPTO_SYM_OP_NONE: no operation;

> >> VIRTIO_CRYPTO_SYM_OP_CIPHER: Cipher only

> >>> +operation on the data;

> VIRTIO_CRYPTO_SYM_OP_ALGORITHM_CHAINING:

> >> Chain any cipher with any hash

> >>> +or mac operation.

> >>> +

> >> Based on the stuff written here, it ain't obvious to me at which offset does

> >> the device writable part (that is virtio_crypto_session_input) start.

> >>

> > Why do we need to know the offset? IMO we only need to follow the spec

> arrangement to

> > fill the specific request packet will not be a problem, such as general header +

> out_data + in_data.

> > Driver first complete read-only part, then the writable part. The device then

> parses the

> > request packet this way. Why do we need to write this offset in the spec?

> >

> 

> We actually don't. That is just what I've said a couple of lines before.

> But we do need to know at which offset the key is (or any other piece of

> information within the device readable and the device writable part).

> 

> Maybe it was not smart from me to ask this question.

> 

> I understood this specification as if it were trying to describe a message

> format as structs, which are basically supposed to define the offset of the

> individual fields. So for a guy trying to figure out the spec (because he

> wants to implement it) asking himself at what offset a certain piece

> of info is, is natural IMHO.

> 

OK, I agree. The cipher key offset is 72. Will add some more description about those
parameters.

> I don't think the placement of virtio_crypto_session_input is adequately

> described. Please point me to the fragment if I've missed it. IMHO a

> straightforward way to describe it would be that virtio_crypto_session_input

> starts at the data address designated by the first device writable descriptor.

> 

Make sense to me. Thanks!

> Regards,

> Halil

> 

> >> From your kernel code, it seems to me that it starts at offset 72 + keylen.

> >>

> >>

> >> To sum it up I'm awfully dissatisfied. Maybe I made some mistake

> somewhere,

> >> and that's why things don't make sense.

> >>

> >> I would really appreciate somebody else having a look, and telling:

> >> is it possible to figure out the message formats and create an inter-operable

> >> implementation based on this text (and without looking at the Linux/QEMU

> >> code)?

> >>

> > Yes, we need some other comments about this.

> > > Thanks,

> > -Gonglei
diff mbox series

Patch

diff --git a/acknowledgements.tex b/acknowledgements.tex
index 6c86d12..c4b6844 100644
--- a/acknowledgements.tex
+++ b/acknowledgements.tex
@@ -26,6 +26,8 @@  Sasha Levin,	Oracle	\newline
 Sergey Tverdyshev,	Thales e-Security	\newline
 Stefan Hajnoczi,	Red Hat	\newline
 Tom Lyon,	Samya Systems, Inc.	\newline
+Lei Gong,	Huawei	\newline
+Peng Long,	Huawei	\newline
 \end{oasistitlesection}
 
 The following non-members have provided valuable feedback on this
@@ -43,4 +45,5 @@  Laura Novich, Red Hat	\newline
 Patrick Durusau,	Technical Advisory Board, OASIS	\newline
 Thomas Huth,	IBM	\newline
 Yan Vugenfirer, Red Hat / Daynix	\newline
+Halil Pasic,	IBM	\newline
 \end{oasistitlesection}
diff --git a/content.tex b/content.tex
index d989d98..7710f8c 100644
--- a/content.tex
+++ b/content.tex
@@ -5641,6 +5641,8 @@  descriptor for the \field{sense_len}, \field{residual},
 \field{status_qualifier}, \field{status}, \field{response} and
 \field{sense} fields.
 
+\input{virtio-crypto.tex}
+
 \chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits}
 
 Currently there are three device-independent feature bits defined:
diff --git a/virtio-crypto.tex b/virtio-crypto.tex
new file mode 100644
index 0000000..361c9ab
--- /dev/null
+++ b/virtio-crypto.tex
@@ -0,0 +1,1426 @@ 
+\section{Crypto Device}\label{sec:Device Types / Crypto Device}
+
+The virtio crypto device is a virtual cryptography device as well as a
+virtual cryptographic accelerator. The virtio crypto device provides the
+following crypto services: CIPHER, MAC, HASH, and AEAD. Virtio crypto
+devices have a single control queue and at least one data queue. Crypto
+operation requests are placed into a data queue, and serviced by the
+device. Some crypto operation requests are only valid in the context of a
+session. The role of the control queue is facilitating control operation
+requests. Sessions management is realized with control operation
+requests.
+
+\subsection{Device ID}\label{sec:Device Types / Crypto Device / Device ID}
+
+20
+
+\subsection{Virtqueues}\label{sec:Device Types / Crypto Device / Virtqueues}
+
+\begin{description}
+\item[0] dataq1
+\item[\ldots]
+\item[N-1] dataqN
+\item[N] controlq
+\end{description}
+
+N is set by \field{max_dataqueues}.
+
+\subsection{Feature bits}\label{sec:Device Types / Crypto Device / Feature bits}
+
+\begin{description}
+\item VIRTIO_CRYPTO_F_MUX_MODE (0) multiplexing mode is available.
+\item VIRTIO_CRYPTO_F_CIPHER_STATELESS_MODE (1) stateless mode is available for CIPHER service.
+\item VIRTIO_CRYPTO_F_HASH_STATELESS_MODE (2) stateless mode is available for HASH service.
+\item VIRTIO_CRYPTO_F_MAC_STATELESS_MODE (3) stateless mode is available for MAC service.
+\item VIRTIO_CRYPTO_F_AEAD_STATELESS_MODE (4) stateless mode is available for AEAD service.
+\end{description}
+
+\subsubsection{Feature bit requirements}\label{sec:Device Types / Crypto Device / Feature bits}
+
+Some crypto feature bits require other crypto feature bits
+(see \ref{drivernormative:Basic Facilities of a Virtio Device / Feature Bits}):
+
+\begin{description}
+\item[VIRTIO_CRYPTO_F_CIPHER_STATELESS_MODE] Requires VIRTIO_CRYPTO_F_MUX_MODE.
+\item[VIRTIO_CRYPTO_F_HASH_STATELESS_MODE] Requires VIRTIO_CRYPTO_F_MUX_MODE.
+\item[VIRTIO_CRYPTO_F_MAC_STATELESS_MODE] Requires VIRTIO_CRYPTO_F_MUX_MODE.
+\item[VIRTIO_CRYPTO_F_AEAD_STATELESS_MODE] Requires VIRTIO_CRYPTO_F_MUX_MODE.
+\end{description}
+
+\subsection{Supported crypto services}\label{sec:Device Types / Crypto Device / Supported crypto services}
+
+The following crypto services are defined:
+
+\begin{lstlisting}
+/* CIPHER service */
+#define VIRTIO_CRYPTO_SERVICE_CIPHER 0
+/* HASH service */
+#define VIRTIO_CRYPTO_SERVICE_HASH   1
+/* MAC (Message Authentication Codes) service */
+#define VIRTIO_CRYPTO_SERVICE_MAC    2
+/* AEAD (Authenticated Encryption with Associated Data) service */
+#define VIRTIO_CRYPTO_SERVICE_AEAD   3
+\end{lstlisting}
+
+The above constants designate bits used to indicate the which of crypto services are
+offered by the device as described in, see \ref{sec:Device Types / Crypto Device / Device configuration layout}.
+
+\subsubsection{CIPHER services}\label{sec:Device Types / Crypto Device / Supported crypto services / CIPHER services}
+
+The following CIPHER algorithms are defined:
+
+\begin{lstlisting}
+#define VIRTIO_CRYPTO_NO_CIPHER                 0
+#define VIRTIO_CRYPTO_CIPHER_ARC4               1
+#define VIRTIO_CRYPTO_CIPHER_AES_ECB            2
+#define VIRTIO_CRYPTO_CIPHER_AES_CBC            3
+#define VIRTIO_CRYPTO_CIPHER_AES_CTR            4
+#define VIRTIO_CRYPTO_CIPHER_DES_ECB            5
+#define VIRTIO_CRYPTO_CIPHER_DES_CBC            6
+#define VIRTIO_CRYPTO_CIPHER_3DES_ECB           7
+#define VIRTIO_CRYPTO_CIPHER_3DES_CBC           8
+#define VIRTIO_CRYPTO_CIPHER_3DES_CTR           9
+#define VIRTIO_CRYPTO_CIPHER_KASUMI_F8          10
+#define VIRTIO_CRYPTO_CIPHER_SNOW3G_UEA2        11
+#define VIRTIO_CRYPTO_CIPHER_AES_F8             12
+#define VIRTIO_CRYPTO_CIPHER_AES_XTS            13
+#define VIRTIO_CRYPTO_CIPHER_ZUC_EEA3           14
+\end{lstlisting}
+
+The above constants have two usages:
+\begin{enumerate}
+\item As bit numbers, used to tell the driver which CIPHER algorithms
+are supported by the device, see \ref{sec:Device Types / Crypto Device / Device configuration layout}.
+\item As values, used to designate the algorithm in (CIPHER type) crypto
+operation requests, see \ref{sec:Device Types / Crypto Device / Device Operation / Control Virtqueue / Session operation}.
+\end{enumerate}
+
+\subsubsection{HASH services}\label{sec:Device Types / Crypto Device / Supported crypto services / HASH services}
+
+The following HASH algorithms are defined:
+
+\begin{lstlisting}
+#define VIRTIO_CRYPTO_NO_HASH            0
+#define VIRTIO_CRYPTO_HASH_MD5           1
+#define VIRTIO_CRYPTO_HASH_SHA1          2
+#define VIRTIO_CRYPTO_HASH_SHA_224       3
+#define VIRTIO_CRYPTO_HASH_SHA_256       4
+#define VIRTIO_CRYPTO_HASH_SHA_384       5
+#define VIRTIO_CRYPTO_HASH_SHA_512       6
+#define VIRTIO_CRYPTO_HASH_SHA3_224      7
+#define VIRTIO_CRYPTO_HASH_SHA3_256      8
+#define VIRTIO_CRYPTO_HASH_SHA3_384      9
+#define VIRTIO_CRYPTO_HASH_SHA3_512      10
+#define VIRTIO_CRYPTO_HASH_SHA3_SHAKE128      11
+#define VIRTIO_CRYPTO_HASH_SHA3_SHAKE256      12
+\end{lstlisting}
+
+The above constants have two usages:
+\begin{enumerate}
+\item As bit numbers, used to tell the driver which HASH algorithms
+are supported by the device, see \ref{sec:Device Types / Crypto Device / Device configuration layout}.
+\item As values, used to designate the algorithm in (HASH type) crypto
+operation requires, see \ref{sec:Device Types / Crypto Device / Device Operation / Control Virtqueue / Session operation}.
+\end{enumerate}
+
+\subsubsection{MAC services}\label{sec:Device Types / Crypto Device / Supported crypto services / MAC services}
+
+The following MAC algorithms are defined:
+
+\begin{lstlisting}
+#define VIRTIO_CRYPTO_NO_MAC                       0
+#define VIRTIO_CRYPTO_MAC_HMAC_MD5                 1
+#define VIRTIO_CRYPTO_MAC_HMAC_SHA1                2
+#define VIRTIO_CRYPTO_MAC_HMAC_SHA_224             3
+#define VIRTIO_CRYPTO_MAC_HMAC_SHA_256             4
+#define VIRTIO_CRYPTO_MAC_HMAC_SHA_384             5
+#define VIRTIO_CRYPTO_MAC_HMAC_SHA_512             6
+#define VIRTIO_CRYPTO_MAC_CMAC_3DES                25
+#define VIRTIO_CRYPTO_MAC_CMAC_AES                 26
+#define VIRTIO_CRYPTO_MAC_KASUMI_F9                27
+#define VIRTIO_CRYPTO_MAC_SNOW3G_UIA2              28
+#define VIRTIO_CRYPTO_MAC_GMAC_AES                 41
+#define VIRTIO_CRYPTO_MAC_GMAC_TWOFISH             42
+#define VIRTIO_CRYPTO_MAC_CBCMAC_AES               49
+#define VIRTIO_CRYPTO_MAC_CBCMAC_KASUMI_F9         50
+#define VIRTIO_CRYPTO_MAC_XCBC_AES                 53
+#define VIRTIO_CRYPTO_MAC_ZUC_EIA3                 54
+\end{lstlisting}
+
+The above constants have two usages:
+\begin{enumerate}
+\item As bit numbers, used to tell the driver which MAC algorithms
+are supported by the device, see \ref{sec:Device Types / Crypto Device / Device configuration layout}.
+\item As values, used to designate the algorithm in (MAC type) crypto
+operation requests, see \ref{sec:Device Types / Crypto Device / Device Operation / Control Virtqueue / Session operation}.
+\end{enumerate}
+
+\subsubsection{AEAD services}\label{sec:Device Types / Crypto Device / Supported crypto services / AEAD services}
+
+The following AEAD algorithms are defined:
+
+\begin{lstlisting}
+#define VIRTIO_CRYPTO_NO_AEAD     0
+#define VIRTIO_CRYPTO_AEAD_GCM    1
+#define VIRTIO_CRYPTO_AEAD_CCM    2
+#define VIRTIO_CRYPTO_AEAD_CHACHA20_POLY1305  3
+\end{lstlisting}
+
+The above constants have two usages:
+\begin{enumerate}
+\item As bit numbers, used to tell the driver which AEAD algorithms
+are supported by the device, see \ref{sec:Device Types / Crypto Device / Device configuration layout}.
+\item As values, used to designate the algorithm in (DEAD type) crypto
+operation requests, see \ref{sec:Device Types / Crypto Device / Device Operation / Control Virtqueue / Session operation}.
+\end{enumerate}
+
+\subsection{Device configuration layout}\label{sec:Device Types / Crypto Device / Device configuration layout}
+
+\begin{lstlisting}
+struct virtio_crypto_config {
+    le32 status;
+    le32 max_dataqueues;
+    le32 crypto_services;
+    /* Detailed algorithms mask */
+    le32 cipher_algo_l;
+    le32 cipher_algo_h;
+    le32 hash_algo;
+    le32 mac_algo_l;
+    le32 mac_algo_h;
+    le32 aead_algo;
+    /* Maximum length of cipher key in bytes */
+    le32 max_cipher_key_len;
+    /* Maximum length of authenticated key in bytes */
+    le32 max_auth_key_len;
+    le32 reserved;
+    /* Maximum size of each crypto request's content in bytes */
+    le64 max_size;
+};
+\end{lstlisting}
+
+\begin{description}
+\item Currently, only one \field(status) bit is defined: VIRTIO_CRYPTO_S_HW_READY
+    set indicates that the device is ready to process requests, this bit is read-only
+    for the driver
+\begin{lstlisting}
+#define VIRTIO_CRYPTO_S_HW_READY  (1 << 0)
+\end{lstlisting}
+
+\item[\field{max_dataqueues}] is the maximum number of data virtqueues that can
+    be configured by the device. The driver MAY use only one data queue, or it
+    can use more to achieve better performance.
+
+\item[\field{crypto_services}] crypto service offered, see \ref{sec:Device Types / Crypto Device / Supported crypto services}.
+
+\item[\field{cipher_algo_l}] CIPHER algorithms bits 0-31, see \ref{sec:Device Types / Crypto Device / Supported crypto services  / CIPHER services}.
+
+\item[\field{cipher_algo_h}] CIPHER algorithms bits 32-63, see \ref{sec:Device Types / Crypto Device / Supported crypto services  / CIPHER services}.
+
+\item[\field{hash_algo}] HASH algorithms bits, see \ref{sec:Device Types / Crypto Device / Supported crypto services  / HASH services}.
+
+\item[\field{mac_algo_l}] MAC algorithms bits 0-31, see \ref{sec:Device Types / Crypto Device / Supported crypto services  / MAC services}.
+
+\item[\field{mac_algo_h}] MAC algorithms bits 32-63, see \ref{sec:Device Types / Crypto Device / Supported crypto services  / MAC services}.
+
+\item[\field{aead_algo}] AEAD algorithms bits, see \ref{sec:Device Types / Crypto Device / Supported crypto services  / AEAD services}.
+
+\item[\field{max_cipher_key_len}] is the maximum length of cipher key supported by the device.
+
+\item[\field{max_auth_key_len}] is the maximum length of authenticated key supported by the device.
+
+\item[\field{reserved}] is reserved for future use.
+
+\item[\field{max_size}] is the maximum size of each crypto request's content supported by the device
+\end{description}
+
+\begin{note}
+Unless explicitly stated otherwise all lengths and sizes are in bytes.
+\end{note}
+
+\devicenormative{\subsubsection}{Device configuration layout}{Device Types / Crypto Device / Device configuration layout}
+
+\begin{itemize*}
+\item The device MUST set \field{max_dataqueues} to between 1 and 65535 inclusive.
+\item The device MUST set the \field{status} with valid flags, undefined flags MUST NOT be set.
+\item The device MUST accept and handle requests after \field{status} is set to VIRTIO_CRYPTO_S_HW_READY.
+\item The device MUST set \field{crypto_services} based on the crypto services the device offers.
+\item The device MUST set detailed algorithms masks for each service advertised by \field{crypto_services}.
+    The device MUST NOT set the not defined algorithms bits.
+\item The device MUST set \field{max_size} to show the maximum size of crypto request the device supports.
+\item The device MUST set \field{max_cipher_key_len} to show the maximum length of cipher key if the
+    device supports CIPHER service.
+\item The device MUST set \field{max_auth_key_len} to show the maximum length of authenticated key if
+    the device supports MAC service.
+\end{itemize*}
+
+\drivernormative{\subsubsection}{Device configuration layout}{Device Types / Crypto Device / Device configuration layout}
+
+\begin{itemize*}
+\item The driver MUST read the \field{status} from the bottom bit of status to check whether the
+    VIRTIO_CRYPTO_S_HW_READY is set, and the driver MUST reread it after device reset.
+\item The driver MUST NOT transmit any requests to the device if the VIRTIO_CRYPTO_S_HW_READY is not set.
+\item The driver MUST read \field{max_dataqueues} field to discover the number of data queues the device supports.
+\item The driver MUST read \field{crypto_services} field to discover which services the device is able to offer.
+\item The driver SHOULD ignore the not defined algorithms bits.
+\item The driver MUST read the detailed algorithms fields based on \field{crypto_services} field.
+\item The driver SHOULD read \field{max_size} to discover the maximum size of crypto request the device supports.
+\item The driver SHOULD read \field{max_cipher_key_len} to discover the maximum length of cipher key
+    the device supports.
+\item The driver SHOULD read \field{max_auth_key_len} to discover the maximum length of authenticated
+    key the device supports.
+\end{itemize*}
+
+\subsection{Device Initialization}\label{sec:Device Types / Crypto Device / Device Initialization}
+
+\drivernormative{\subsubsection}{Device Initialization}{Device Types / Crypto Device / Device Initialization}
+
+\begin{itemize*}
+\item The driver MUST configure and initialize all virtqueues.
+\item The driver MUST read the supported crypto services from bits of \field{crypto_services}.
+\item The driver MUST read the supported algorithms based on \field{crypto_services} field.
+\end{itemize*}
+
+\subsection{Device Operation}\label{sec:Device Types / Crypto Device / Device Operation}
+
+The operation of a virtio crypto device is driven by requests placed on the virtqueues.
+Requests consist of a queue-type specific header (specifying among others the operation)
+and an operation specific payload. The payload is generally composed of operation
+parameters, output data, and input data. Operation parameters are crypto-service-specific
+parameters, output data is the data that should be utilized in operations, and input
+data is equal to "operation result + result data".
+
+If VIRTIO_CRYPTO_F_MUX_MODE is negotioated the device may support both session mode
+(See \ref{sec:Device Types / Crypto Device / Device Operation / Control Virtqueue / Session operation})
+and stateless mode operation requests.
+In stateless mode all operation parameters are supplied as a part of each request,
+while in session mode, some or all operation parameters are managed within the
+session. Stateless mode is guarded by feature bits 0-4 on a service level. If
+stateless mode is negotiated for a service, the service is available both in
+session and stateless mode; otherwise it's only available in session mode.
+
+\subsubsection{Operation Status}\label{sec:Device Types / Crypto Device / Device Operation / Operation status}
+The device MUST return a status code as part of the operation (both session
+operation and service operation) result. The valid operation status as follows:
+
+\begin{lstlisting}
+enum VIRTIO_CRYPTO_STATUS {
+    VIRTIO_CRYPTO_OK = 0,
+    VIRTIO_CRYPTO_ERR = 1,
+    VIRTIO_CRYPTO_BADMSG = 2,
+    VIRTIO_CRYPTO_NOTSUPP = 3,
+    VIRTIO_CRYPTO_INVSESS = 4,
+    VIRTIO_CRYPTO_NOSPC = 5,
+    VIRTIO_CRYPTO_MAX
+};
+\end{lstlisting}
+
+\begin{itemize*}
+\item VIRTIO_CRYPTO_OK: success.
+\item VIRTIO_CRYPTO_BADMSG: authentication failed (only when AEAD decryption).
+\item VIRTIO_CRYPTO_NOTSUPP: operation or algorithm is unsupported.
+\item VIRTIO_CRYPTO_INVSESS: invalid session ID when executing crypto operations.
+\item VIRTIO_CRYPTO_NOSPC: no free session ID (only when the VIRTIO_CRYPTO_F_MUX_MODE
+    feature bit is negotiated).
+\item VIRTIO_CRYPTO_ERR: any failure not mentioned above occurs.
+\end{itemize*}
+
+\subsubsection{Control Virtqueue}\label{sec:Device Types / Crypto Device / Device Operation / Control Virtqueue}
+
+The driver uses the control virtqueue to send control commands to the
+device, such as session operations (See \ref{sec:Device Types / Crypto Device / Device Operation / Control Virtqueue / Session operation}).
+
+The header for controlq is of the following form:
+\begin{lstlisting}
+#define VIRTIO_CRYPTO_OPCODE(service, op)   (((service) << 8) | (op))
+
+struct virtio_crypto_ctrl_header {
+#define VIRTIO_CRYPTO_CIPHER_CREATE_SESSION \
+       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_CIPHER, 0x02)
+#define VIRTIO_CRYPTO_CIPHER_DESTROY_SESSION \
+       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_CIPHER, 0x03)
+#define VIRTIO_CRYPTO_HASH_CREATE_SESSION \
+       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_HASH, 0x02)
+#define VIRTIO_CRYPTO_HASH_DESTROY_SESSION \
+       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_HASH, 0x03)
+#define VIRTIO_CRYPTO_MAC_CREATE_SESSION \
+       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_MAC, 0x02)
+#define VIRTIO_CRYPTO_MAC_DESTROY_SESSION \
+       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_MAC, 0x03)
+#define VIRTIO_CRYPTO_AEAD_CREATE_SESSION \
+       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_AEAD, 0x02)
+#define VIRTIO_CRYPTO_AEAD_DESTROY_SESSION \
+       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_AEAD, 0x03)
+    le32 opcode;
+    /* algo should be service-specific algorithms */
+    le32 algo;
+    le32 flag;
+    le32 reserved;
+};
+\end{lstlisting}
+
+The controlq request is composed of two parts:
+\begin{lstlisting}
+struct virtio_crypto_op_ctrl_req {
+    struct virtio_crypto_ctrl_header header;
+
+    /* additional paramenter */
+    u8 additional_para[addl_para_len];
+};
+\end{lstlisting}
+
+The first is a general header (see above). And the second one, additional
+paramenter, contains an crypto-service-specific structure, which could be one
+of the following types:
+\begin{itemize*}
+\item struct virtio_crypto_sym_create_session_req
+\item struct virtio_crypto_hash_create_session_req
+\item struct virtio_crypto_mac_create_session_req
+\item struct virtio_crypto_aead_create_session_req
+\item virtio_crypto_destroy_session_req
+\end{itemize*}
+
+The size of the additional paramenter depends on the VIRTIO_CRYPTO_F_MUX_MODE
+feature bit:
+\item If the VIRTIO_CRYPTO_F_MUX_MODE feature bit is NOT negotiated, the
+    size of additional paramenter is fixed to 56 bytes, the data of the unused
+    part (if has) will be ingored.
+\item If the VIRTIO_CRYPTO_F_MUX_MODE feature bit is negotiated, the size of
+    additional paramenter is flexible, which is the same as the crypto-service-specific
+    structure used.
+
+\paragraph{Session operation}\label{sec:Device Types / Crypto Device / Device Operation / Control Virtqueue / Session operation}
+
+The session is a handle which describes the cryptographic parameters to be
+applied to a number of buffers.
+
+The following structure stores the result of session creation set by the device:
+
+\begin{lstlisting}
+struct virtio_crypto_session_input {
+    /* Device-writable part */
+    le64 session_id;
+    le32 status;
+    le32 padding;
+};
+\end{lstlisting}
+
+A request to destroy a session includes the following information:
+
+\begin{lstlisting}
+struct virtio_crypto_destroy_session_req {
+    /* Device-readable part */
+    le64  session_id;
+    /* Device-writable part */
+    le32  status;
+    le32  padding;
+};
+\end{lstlisting}
+
+\subparagraph{Session operation: HASH session}\label{sec:Device Types / Crypto Device / Device
+Operation / Control Virtqueue / Session operation / Session operation: HASH session}
+
+HASH session requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_hash_session_para {
+    /* See VIRTIO_CRYPTO_HASH_* above */
+    le32 algo;
+    /* hash result length */
+    le32 hash_result_len;
+};
+struct virtio_crypto_hash_create_session_req {
+    /* Device-readable part */
+    struct virtio_crypto_hash_session_para para;
+    /* Device-writable part */
+    struct virtio_crypto_session_input input;
+};
+\end{lstlisting}
+
+The information required by HASH session creation is stored in the
+virtio_crypto_hash_create_session_req structure, including the hash
+parameters stored in \field{para}. \field{input} stores the result of
+this operation.
+
+\subparagraph{Session operation: MAC session}\label{sec:Device Types / Crypto Device / Device
+Operation / Control Virtqueue / Session operation / Session operation: MAC session}
+
+MAC session requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_mac_session_para {
+    /* See VIRTIO_CRYPTO_MAC_* above */
+    le32 algo;
+    /* hash result length */
+    le32 hash_result_len;
+    /* length of authenticated key */
+    le32 auth_key_len;
+    le32 padding;
+};
+
+struct virtio_crypto_mac_create_session_req {
+    /* Device-readable part */
+    struct virtio_crypto_mac_session_para para;
+    /* The authenticated key */
+    u8 auth_key[auth_key_len];
+
+    /* Device-writable part */
+    struct virtio_crypto_session_input input;
+};
+\end{lstlisting}
+
+The information required by MAC session creation is stored in the
+virtio_crypto_mac_create_session_req structure, including the mac
+parameters stored in \field{para} and the authenticated key in \field{auth_key}.
+\field{input} stores the result of this operation.
+
+\subparagraph{Session operation: Symmetric algorithms session}\label{sec:Device Types / Crypto Device / Device
+Operation / Control Virtqueue / Session operation / Session operation: Symmetric algorithms session}
+
+The request of symmetric session includes two parts, CIPHER algorithms
+and chain algorithms (chaining CIPHER and HASH/MAC).
+
+CIPHER session requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_cipher_session_para {
+    /* See VIRTIO_CRYPTO_CIPHER* above */
+    le32 algo;
+    /* length of key */
+    le32 keylen;
+#define VIRTIO_CRYPTO_OP_ENCRYPT  1
+#define VIRTIO_CRYPTO_OP_DECRYPT  2
+    /* encryption or decryption */
+    le32 op;
+    le32 padding;
+};
+
+struct virtio_crypto_cipher_session_req {
+    /* Device-readable part */
+    struct virtio_crypto_cipher_session_para para;
+    /* The cipher key */
+    u8 cipher_key[keylen];
+
+    /* Device-writable part */
+    struct virtio_crypto_session_input input;
+};
+\end{lstlisting}
+
+Algorithm chaining requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_alg_chain_session_para {
+#define VIRTIO_CRYPTO_SYM_ALG_CHAIN_ORDER_HASH_THEN_CIPHER  1
+#define VIRTIO_CRYPTO_SYM_ALG_CHAIN_ORDER_CIPHER_THEN_HASH  2
+    le32 alg_chain_order;
+/* Plain hash */
+#define VIRTIO_CRYPTO_SYM_HASH_MODE_PLAIN    1
+/* Authenticated hash (mac) */
+#define VIRTIO_CRYPTO_SYM_HASH_MODE_AUTH     2
+/* Nested hash */
+#define VIRTIO_CRYPTO_SYM_HASH_MODE_NESTED   3
+    le32 hash_mode;
+    struct virtio_crypto_cipher_session_para cipher_param;
+
+    /*
+     * The additional_para is fixed to 16 bytes in length, it
+     * contains a virtio_crypto_hash_session_para structure or
+     * a virtio_crypto_mac_session_para structure and the data
+     * of unused part (if has) will be ingored.
+     */
+#define VIRTIO_CRYPTO_ALG_CHAIN_SESS_PARA_SIZE  16
+    u8 additional_para[VIRTIO_CRYPTO_ALG_CHAIN_SESS_PARA_SIZE];
+
+    /* length of the additional authenticated data (AAD) in bytes */
+    le32 aad_len;
+    le32 padding;
+};
+
+struct virtio_crypto_alg_chain_session_req {
+    /* Device-readable part */
+    struct virtio_crypto_alg_chain_session_para para;
+    /* The cipher key */
+    u8 cipher_key[keylen];
+    /* The authenticated key */
+    u8 auth_key[auth_key_len];
+
+    /* Device-writable part */
+    struct virtio_crypto_session_input input;
+};
+\end{lstlisting}
+
+Symmetric algorithm requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_sym_create_session_req {
+    /*
+     * The additional_para is fixed to 48 bytes in length, it
+     * contains a virtio_crypto_cipher_session_req structure or
+     * a virtio_crypto_alg_chain_session_req structure and the
+     * data of unused part (if has) will be ingored.
+     */
+#define VIRTIO_CRYPTO_SYM_CREATE_SESS_PARA_SIZE  48
+    u8 additional_para[VIRTIO_CRYPTO_SYM_CREATE_SESS_PARA_SIZE];
+
+    /* Device-readable part */
+
+/* No operation */
+#define VIRTIO_CRYPTO_SYM_OP_NONE  0
+/* Cipher only operation on the data */
+#define VIRTIO_CRYPTO_SYM_OP_CIPHER  1
+/* Chain any cipher with any hash or mac operation. The order
+   depends on the value of alg_chain_order param */
+#define VIRTIO_CRYPTO_SYM_OP_ALGORITHM_CHAINING  2
+    le32 op_type;
+    le32 padding;
+};
+\end{lstlisting}
+
+The information required by symmetric algorithms session creation is stored in the
+virtio_crypto_sym_create_session_req structure, including the symmetric operation
+type in \field{op_type} and the cipher parameters stored in \field{cipher} or the
+algorithm chaining paramenters in \field{chain}.
+
+The driver can set the \field{op_type} field in struct virtio_crypto_sym_create_session_req
+as follows: VIRTIO_CRYPTO_SYM_OP_NONE: no operation; VIRTIO_CRYPTO_SYM_OP_CIPHER: Cipher only
+operation on the data; VIRTIO_CRYPTO_SYM_OP_ALGORITHM_CHAINING: Chain any cipher with any hash
+or mac operation.
+
+\subparagraph{Session operation: AEAD session}\label{sec:Device Types / Crypto Device / Device
+Operation / Control Virtqueue / Session operation / Session operation: AEAD session}
+
+AEAD session requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_aead_session_para {
+    /* See VIRTIO_CRYPTO_AEAD_* above */
+    le32 algo;
+    /* length of key */
+    le32 key_len;
+    /* Authentication tag length */
+    le32 tag_len;
+    /* The length of the additional authenticated data (AAD) in bytes */
+    le32 aad_len;
+    /* encryption or decryption, See above VIRTIO_CRYPTO_OP_* */
+    le32 op;
+    le32 padding;
+};
+
+struct virtio_crypto_aead_create_session_req {
+    /* Device-readable part */
+    struct virtio_crypto_aead_session_para para;
+    u8 key[key_len];
+
+    /* Device-writeable part */
+    struct virtio_crypto_session_input input;
+};
+\end{lstlisting}
+
+The information required by AEAD session creation is stored in the virtio_crypto_aead_create_session_req
+structure, including the aead parameters stored in \field{para} and the cipher key in \field{key}.
+\field{input} stores the result of this operation.
+
+\drivernormative{\subparagraph}{Session operation: create session}{Device Types / Crypto Device / Device Operation / Control Virtqueue / Session operation / Session operation: create session}
+
+\begin{itemize*}
+\item The driver MUST set the control general header and the corresponding crypto-service-specific
+    structure. See \ref{sec:Device Types / Crypto Device / Device Operation / Control Virtqueue}.
+\item The driver MUST set the \field{opcode} field based on service type: CIPHER, HASH, MAC, or AEAD.
+\item The driver MUST set the \field{reversed} field to zero.
+\end{itemize*}
+
+\devicenormative{\subparagraph}{Session operation: create session}{Device Types / Crypto Device / Device
+Operation / Control Virtqueue / Session operation / Session operation: create session}
+
+\begin{itemize*}
+\item The device MUST use the corresponding crypto-service-specific structure according to the
+    \field{opcode} in the control general header.
+\item The device MUST set the \field{status} field to one of the following values of enum
+    VIRTIO_CRYPTO_STATUS after finish a session creation:
+\begin{itemize*}
+\item VIRTIO_CRYPTO_OK if a session is created successfully.
+\item VIRTIO_CRYPTO_NOTSUPP if the requested algorithm or operation is unsupported.
+\item VIRTIO_CRYPTO_NOSPC if no free session ID (only when the VIRTIO_CRYPTO_F_MUX_MODE
+    feature bit is negotiated).
+\item VIRTIO_CRYPTO_ERR if failure not mentioned above occurs.
+\end{itemize*}
+\item The device MUST set the \field{session_id} field to a unique session identifier only
+    if the status is set to VIRTIO_CRYPTO_OK.
+\end{itemize*}
+
+\drivernormative{\subparagraph}{Session operation: destroy session}{Device Types / Crypto Device / Device
+Operation / Control Virtqueue / Session operation / Session operation: destroy session}
+
+\begin{itemize*}
+\item The driver MUST set the \field{opcode} field based on service type: CIPHER, HASH, MAC, or AEAD.
+\item The driver MUST set the \field{session_id} to a valid value assigned by the device
+    when the session was created.
+\end{itemize*}
+
+\devicenormative{\subparagraph}{Session operation: destroy session}{Device Types / Crypto Device / Device
+Operation / Control Virtqueue / Session operation / Session operation: destroy session}
+
+\begin{itemize*}
+\item The device MUST set the \field{status} field to one of the following values of enum VIRTIO_CRYPTO_STATUS.
+\begin{itemize*}
+\item VIRTIO_CRYPTO_OK if a session is created successfully.
+\item VIRTIO_CRYPTO_ERR if any failure occurs.
+\end{itemize*}
+\end{itemize*}
+
+\subsubsection{Data Virtqueue}\label{sec:Device Types / Crypto Device / Device Operation / Data Virtqueue}
+
+The driver uses the data virtqueues to transmit crypto operation requests to the device,
+and completes the crypto operations.
+
+The header for dataq is as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_op_header {
+#define VIRTIO_CRYPTO_CIPHER_ENCRYPT \
+    VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_CIPHER, 0x00)
+#define VIRTIO_CRYPTO_CIPHER_DECRYPT \
+    VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_CIPHER, 0x01)
+#define VIRTIO_CRYPTO_HASH \
+    VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_HASH, 0x00)
+#define VIRTIO_CRYPTO_MAC \
+    VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_MAC, 0x00)
+#define VIRTIO_CRYPTO_AEAD_ENCRYPT \
+    VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_AEAD, 0x00)
+#define VIRTIO_CRYPTO_AEAD_DECRYPT \
+    VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_AEAD, 0x01)
+    le32 opcode;
+    /* algo should be service-specific algorithms */
+    le32 algo;
+    le64 session_id;
+#define VIRTIO_CRYPTO_FLAG_SESSION_MODE 1
+    /* control flag to control the request */
+    le32 flag;
+    le32 padding;
+};
+\end{lstlisting}
+
+The dataq request is composed of two parts:
+\begin{lstlisting}
+struct virtio_crypto_op_data_req {
+    struct virtio_crypto_op_header header;
+
+    /* additional paramenter */
+    u8 additional_para[addl_para_len];
+};
+\end{lstlisting}
+
+The first is a general header (see above). And the second one, additional
+paramenter, contains an crypto-service-specific structure, which MUST be one
+of the following types:
+\begin{itemize*}
+\item struct virtio_crypto_sym_data_req
+\item struct virtio_crypto_hash_data_req
+\item struct virtio_crypto_mac_data_req
+\item struct virtio_crypto_aead_data_req
+\item struct virtio_crypto_sym_data_req_stateless (only for multiplexing mode)
+\item struct virtio_crypto_hash_data_req_stateless (only for multiplexing mode)
+\item struct virtio_crypto_mac_data_req_stateless (only for multiplexing mode)
+\item struct virtio_crypto_aead_data_req_stateless (only for multiplexing mode)
+\end{itemize*}
+
+The size of the additional paramenter depends on the VIRTIO_CRYPTO_F_MUX_MODE
+feature bit:
+\item If the VIRTIO_CRYPTO_F_MUX_MODE feature bit is NOT negotiated, the
+    size of additional paramenter is fixed to 48 bytes, the data of the unused
+    part (if has) will be ingored.
+\item If the VIRTIO_CRYPTO_F_MUX_MODE feature bit is negotiated, the size of
+    additional paramenter is flexible, which is the same as the crypto-service-specific
+    structure used.
+
+There is a unified input header for all crypto services, is defined as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_inhdr {
+    u8 status;
+};
+\end{lstlisting}
+
+\subsubsection{HASH Service Operation}\label{sec:Device Types / Crypto Device / Device Operation / HASH Service Operation}
+
+Session mode HASH service requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_hash_para {
+    /* length of source data */
+    le32 src_data_len;
+    /* hash result length */
+    le32 hash_result_len;
+};
+
+struct virtio_crypto_hash_data_req {
+    /* Device-readable part */
+    struct virtio_crypto_hash_para para;
+    /* Source data */
+    u8 src_data[src_data_len];
+
+    /* Device-writable part */
+    /* Hash result data */
+    u8 hash_result[hash_result_len];
+    struct virtio_crypto_inhdr inhdr;
+};
+\end{lstlisting}
+
+Each data request uses virtio_crypto_hash_data_req structure to store information
+used to run the HASH operations.
+
+The information includes the hash parameters stored in \field{para}, output data
+and input data. The output data here includes the source data and the input data
+includes the hash result data used to save the results of the HASH operations.
+\field{inhdr} stores the status of executing the HASH operations.
+
+Stateless mode HASH service requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_hash_para_statelesss {
+    struct {
+        /* See VIRTIO_CRYPTO_HASH_* above */
+        le32 algo;
+    } sess_para;
+
+    /* length of source data */
+    le32 src_data_len;
+    /* hash result length */
+    le32 hash_result_len;
+    le32 reserved;
+};
+struct virtio_crypto_hash_data_req_stateless {
+    /* Device-readable part */
+    struct virtio_crypto_hash_para_stateless para;
+    /* Source data */
+    u8 src_data[src_data_len];
+
+    /* Device-writable part */
+    /* Hash result data */
+    u8 hash_result[hash_result_len];
+    struct virtio_crypto_inhdr inhdr;
+};
+\end{lstlisting}
+
+\drivernormative{\paragraph}{HASH Service Operation}{Device Types / Crypto Device / Device Operation / HASH Service Operation}
+
+\begin{itemize*}
+\item If the driver uses the session mode, then the driver MUST set \field{session_id}
+    in struct virtio_crypto_op_header to a valid value assigned by the device when the
+	session was created.
+\item If the VIRTIO_CRYPTO_F_MUX_MODE feature bit is negotiated, the driver MUST use
+    struct virtio_crypto_op_data_req_mux to wrap crypto requests. Otherwise, the driver
+	MUST use struct virtio_crypto_op_data_req.
+\item If the VIRTIO_CRYPTO_F_HASH_STATELESS_MODE feature bit is negotiated, 1) if the
+    driver uses the stateless mode, then the driver MUST set the \field{flag} field in
+	struct virtio_crypto_op_header to VIRTIO_CRYPTO_FLAG_STATELESS_MODE and MUST set the
+	fields in struct virtio_crypto_hash_para_stateless.sess_para, 2) if the driver uses
+	the session mode, then the driver MUST set the \field{flag} field in struct
+	virtio_crypto_op_header to VIRTIO_CRYPTO_FLAG_SESSION_MODE.
+\item The driver MUST set \field{opcode} in struct virtio_crypto_op_header to VIRTIO_CRYPTO_HASH.
+\end{itemize*}
+
+\devicenormative{\paragraph}{HASH Service Operation}{Device Types / Crypto Device / Device Operation / HASH Service Operation}
+
+\begin{itemize*}
+\item If the VIRTIO_CRYPTO_F_MUX_MODE feature bit is negotiated, the device MUST parse
+    the struct virtio_crypto_op_data_req_mux for crypto requests. Otherwise, the device
+	MUST parse the struct virtio_crypto_op_data_req.
+\item The device MUST use the corresponding crypto-service-specific structure according
+    to the \field{opcode} in the data general header.
+\item If the VIRTIO_CRYPTO_F_HASH_STATELESS_MODE feature bit is negotiated, the device
+    MUST parse \field{flag} field in struct virtio_crypto_op_header in order to decide
+	which mode the driver uses.
+\item The device MUST copy the results of HASH operations in the hash_result[] if HASH
+    operations success.
+\item The device MUST set \field{status} in struct virtio_crypto_inhdr to one of the
+    following values of enum VIRTIO_CRYPTO_STATUS:
+\begin{itemize*}
+\item VIRTIO_CRYPTO_OK if the operation success.
+\item VIRTIO_CRYPTO_NOTSUPP if the requested algorithm or operation is unsupported.
+\item VIRTIO_CRYPTO_INVSESS if the session ID invalid when in session mode.
+\item VIRTIO_CRYPTO_ERR if any failure not mentioned above occurs.
+\end{itemize*}
+\end{itemize*}
+
+\subsubsection{MAC Service Operation}\label{sec:Device Types / Crypto Device / Device Operation / MAC Service Operation}
+
+Session mode MAC service requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_mac_para {
+    struct virtio_crypto_hash_para hash;
+};
+
+struct virtio_crypto_mac_data_req {
+    /* Device-readable part */
+    struct virtio_crypto_mac_para para;
+    /* Source data */
+    u8 src_data[src_data_len];
+
+    /* Device-writable part */
+    /* Hash result data */
+    u8 hash_result[hash_result_len];
+    struct virtio_crypto_inhdr inhdr;
+};
+\end{lstlisting}
+
+Each request uses the virtio_crypto_mac_data_req structure to store information
+used to run the MAC operations.
+
+The information includes the hash parameters stored in \field{para}, output data
+and input data. The output data here includes the source data and the input data
+includes the hash result data used to save the results of the MAC operations.
+\field{inhdr} stores the status of executing the MAC operations.
+
+Stateless mode MAC service requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_mac_para_stateless {
+    struct {
+        /* See VIRTIO_CRYPTO_MAC_* above */
+        le32 algo;
+        /* length of authenticated key */
+        le32 auth_key_len;
+    } sess_para;
+
+    /* length of source data */
+    le32 src_data_len;
+    /* hash result length */
+    le32 hash_result_len;
+};
+
+struct virtio_crypto_mac_data_req_stateless {
+    /* Device-readable part */
+    struct virtio_crypto_mac_para_stateless para;
+    /* The authenticated key */
+    u8 auth_key[auth_key_len];
+    /* Source data */
+    u8 src_data[src_data_len];
+
+    /* Device-writable part */
+    /* Hash result data */
+    u8 hash_result[hash_result_len];
+    struct virtio_crypto_inhdr inhdr;
+};
+\end{lstlisting}
+
+\drivernormative{\paragraph}{MAC Service Operation}{Device Types / Crypto Device / Device Operation / MAC Service Operation}
+
+\begin{itemize*}
+\item If the driver uses the session mode, then the driver MUST set \field{session_id}
+    in struct virtio_crypto_op_header to a valid value assigned by the device when the
+	session was created.
+\item If the VIRTIO_CRYPTO_F_MUX_MODE feature bit is negotiated, the driver MUST use
+    struct virtio_crypto_op_data_req_mux to wrap crypto requests. Otherwise, the
+	driver MUST use struct virtio_crypto_op_data_req.
+\item If the VIRTIO_CRYPTO_F_MAC_STATELESS_MODE feature bit is negotiated, 1) if the
+    driver uses the stateless mode, then the driver MUST set the \field{flag} field
+	in struct virtio_crypto_op_header to VIRTIO_CRYPTO_FLAG_STATELESS_MODE and MUST
+	set the fields in struct virtio_crypto_mac_para_stateless.sess_para, 2) if the
+	driver uses the session mode, then the driver MUST set the \field{flag} field in
+	struct virtio_crypto_op_header to VIRTIO_CRYPTO_FLAG_SESSION_MODE.
+\item The driver MUST set \field{opcode} in struct virtio_crypto_op_header to VIRTIO_CRYPTO_MAC.
+\end{itemize*}
+
+\devicenormative{\paragraph}{MAC Service Operation}{Device Types / Crypto Device / Device Operation / MAC Service Operation}
+
+\begin{itemize*}
+\item If the VIRTIO_CRYPTO_F_MUX_MODE feature bit is negotiated, the device MUST parse
+    the struct virtio_crypto_op_data_req_mux for crypto requests. Otherwise, the device
+	MUST parse the struct virtio_crypto_op_data_req.
+\item If the VIRTIO_CRYPTO_F_MAC_STATELESS_MODE feature bit is negotiated, the device
+    MUST parse \field{flag} field in struct virtio_crypto_op_header in order to decide
+	which mode the driver uses.
+\item The device MUST copy the results of MAC operations in the hash_result[] if HASH
+    operations success.
+\item The device MUST set \field{status} in struct virtio_crypto_inhdr to one of the
+    following values of enum VIRTIO_CRYPTO_STATUS:
+\begin{itemize*}
+\item VIRTIO_CRYPTO_OK if the operation success.
+\item VIRTIO_CRYPTO_NOTSUPP if the requested algorithm or operation is unsupported.
+\item VIRTIO_CRYPTO_INVSESS if the session ID invalid when in session mode.
+\item VIRTIO_CRYPTO_ERR if any failure not mentioned above occurs.
+\end{itemize*}
+\end{itemize*}
+
+\subsubsection{Symmetric algorithms Operation}\label{sec:Device Types / Crypto Device / Device Operation / Symmetric algorithms Operation}
+
+Session mode CIPHER service requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_cipher_para {
+    /*
+     * Byte Length of valid IV/Counter data pointed to by the below iv data.
+     *
+     * For block ciphers in CBC or F8 mode, or for Kasumi in F8 mode, or for
+     *   SNOW3G in UEA2 mode, this is the length of the IV (which
+     *   must be the same as the block length of the cipher).
+     * For block ciphers in CTR mode, this is the length of the counter
+     *   (which must be the same as the block length of the cipher).
+     */
+    le32 iv_len;
+    /* length of source data */
+    le32 src_data_len;
+    /* length of destination data */
+    le32 dst_data_len;
+    le32 padding;
+};
+
+struct virtio_crypto_cipher_data_req {
+    /* Device-readable part */
+    struct virtio_crypto_cipher_para para;
+    /*
+     * Initialization Vector or Counter data.
+     *
+     * For block ciphers in CBC or F8 mode, or for Kasumi in F8 mode, or for
+     *   SNOW3G in UEA2 mode, this is the Initialization Vector (IV)
+     *   value.
+     * For block ciphers in CTR mode, this is the counter.
+     * For AES-XTS, this is the 128bit tweak, i, from IEEE Std 1619-2007.
+     *
+     * The IV/Counter will be updated after every partial cryptographic
+     * operation.
+     */
+    u8 iv[iv_len];
+    /* Source data */
+    u8 src_data[src_data_len];
+
+    /* Device-writable part */
+    /* Destination data */
+    u8 dst_data[dst_data_len];
+    struct virtio_crypto_inhdr inhdr;
+};
+\end{lstlisting}
+
+Session mode requests of algorithm chaining are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_alg_chain_data_para {
+    le32 iv_len;
+    /* Length of source data */
+    le32 src_data_len;
+    /* Length of destination data */
+    le32 dst_data_len;
+    /* Starting point for cipher processing in source data */
+    le32 cipher_start_src_offset;
+    /* Length of the source data that the cipher will be computed on */
+    le32 len_to_cipher;
+    /* Starting point for hash processing in source data */
+    le32 hash_start_src_offset;
+    /* Length of the source data that the hash will be computed on */
+    le32 len_to_hash;
+    /* Length of the additional auth data */
+    le32 aad_len;
+    /* Length of the hash result */
+    le32 hash_result_len;
+    le32 reserved;
+};
+
+struct virtio_crypto_alg_chain_data_req {
+    /* Device-readable part */
+    struct virtio_crypto_alg_chain_data_para para;
+    /* Initialization Vector or Counter data */
+    u8 iv[iv_len];
+    /* Source data */
+    u8 src_data[src_data_len];
+    /* Additional authenticated data if exists */
+    u8 aad[aad_len];
+
+    /* Device-writable part */
+    /* Destination data */
+    u8 dst_data[dst_data_len];
+    /* Hash result data */
+    u8 hash_result[hash_result_len];
+    struct virtio_crypto_inhdr inhdr;
+};
+\end{lstlisting}
+
+Session mode requests of symmetric algorithm are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_sym_data_req {
+    /*
+     * The additional_para is fixed to 40 bytes in length, it
+     * contains a virtio_crypto_cipher_data_req structure or
+     * a virtio_crypto_cipher_data_req structure and the data
+     * of unused part (if has) will be ingored.
+     */
+#define VIRTIO_CRYPTO_SYM_DATE_REQ_PARA_SIZE    40
+    u8 additional_para[VIRTIO_CRYPTO_SYM_DATE_REQ_PARA_SIZE];
+
+    /* Device-readable part */
+
+    /* See above VIRTIO_CRYPTO_SYM_OP_* */
+    le32 op_type;
+    le32 padding;
+};
+\end{lstlisting}
+
+Each request uses the virtio_crypto_sym_data_req structure to store information
+used to run the CIPHER operations.
+
+The information includes the cipher parameters stored in \field{para}, output data
+and input data. In the first virtio_crypto_cipher_para structure, \field{iv_len}
+specifies the length of the initialization vector or counter, \field{src_data_len}
+specifies the length of the source data, and \field{dst_data_len} specifies the length
+of the destination data. For plain CIPHER operations, the output data here includes
+the IV/Counter data and source data, and the input data includes the destination data
+used to save the results of the CIPHER operations.
+
+For algorithms chain, the output data here includes the IV/Counter data, source data
+and additional authenticated data if exists. The input data includes both destination
+data and hash result data used to store the results of the HASH/MAC operations.
+\field{inhdr} stores the status of executing the crypto operations.
+
+Stateless mode CIPHER service requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_cipher_para_stateless {
+    struct {
+        /* See VIRTIO_CRYPTO_CIPHER* above */
+        le32 algo;
+        /* length of key */
+        le32 keylen;
+
+        /* See VIRTIO_CRYPTO_OP_* above */
+        le32 op;
+    } sess_para;
+
+    /*
+     * Byte Length of valid IV/Counter data pointed to by the below iv data.
+     */
+    le32 iv_len;
+    /* length of source data */
+    le32 src_data_len;
+    /* length of destination data */
+    le32 dst_data_len;
+};
+
+struct virtio_crypto_cipher_data_req_stateless {
+    /* Device-readable part */
+    struct virtio_crypto_cipher_para_stateless para;
+    /* The cipher key */
+    u8 cipher_key[keylen];
+
+    /* Initialization Vector or Counter data. */
+    u8 iv[iv_len];
+    /* Source data */
+    u8 src_data[src_data_len];
+
+    /* Device-writable part */
+    /* Destination data */
+    u8 dst_data[dst_data_len];
+    struct virtio_crypto_inhdr inhdr;
+};
+\end{lstlisting}
+
+Stateless mode requests of algorithm chaining are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_alg_chain_data_para_stateless {
+    struct {
+        /* See VIRTIO_CRYPTO_SYM_ALG_CHAIN_ORDER_* above */
+        le32 alg_chain_order;
+        /* length of the additional authenticated data in bytes */
+        le32 aad_len;
+
+        struct {
+            /* See VIRTIO_CRYPTO_CIPHER* above */
+            le32 algo;
+            /* length of key */
+            le32 keylen;
+            /* See VIRTIO_CRYPTO_OP_* above */
+            le32 op;
+        } cipher;
+
+        struct {
+            /* See VIRTIO_CRYPTO_HASH_* or VIRTIO_CRYPTO_MAC_* above */
+            le32 algo;
+            /* length of authenticated key */
+            le32 auth_key_len;
+            /* See VIRTIO_CRYPTO_SYM_HASH_MODE_* above */
+            le32 hash_mode;
+        } hash;
+    } sess_para;
+
+    le32 iv_len;
+    /* Length of source data */
+    le32 src_data_len;
+    /* Length of destination data */
+    le32 dst_data_len;
+    /* Starting point for cipher processing in source data */
+    le32 cipher_start_src_offset;
+    /* Length of the source data that the cipher will be computed on */
+    le32 len_to_cipher;
+    /* Starting point for hash processing in source data */
+    le32 hash_start_src_offset;
+    /* Length of the source data that the hash will be computed on */
+    le32 len_to_hash;
+    /* Length of the additional auth data */
+    le32 aad_len;
+    /* Length of the hash result */
+    le32 hash_result_len;
+    le32 reserved;
+};
+
+struct virtio_crypto_alg_chain_data_req_stateless {
+    /* Device-readable part */
+    struct virtio_crypto_alg_chain_data_para_stateless para;
+    /* The cipher key */
+    u8 cipher_key[keylen];
+    /* The auth key */
+    u8 auth_key[auth_key_len];
+    /* Initialization Vector or Counter data */
+    u8 iv[iv_len];
+    /* Additional authenticated data if exists */
+    u8 aad[aad_len];
+    /* Source data */
+    u8 src_data[src_data_len];
+
+    /* Device-writable part */
+    /* Destination data */
+    u8 dst_data[dst_data_len];
+    /* Hash result data */
+    u8 hash_result[hash_result_len];
+    struct virtio_crypto_inhdr inhdr;
+};
+\end{lstlisting}
+
+Stateless mode requests of symmetric algorithm are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_sym_data_req_stateless {
+    /* additional paramenter */
+#define VIRTIO_CRYPTO_SYM_DATE_REQ_PARA_STATELESS_SIZE    72
+    u8 additional_para[VVIRTIO_CRYPTO_SYM_DATE_REQ_PARA_STATELESS_SIZE];
+
+    /* Device-readable part */
+    /* See above VIRTIO_CRYPTO_SYM_OP_* */
+    le32 op_type;
+};
+\end{lstlisting}
+
+\begin{itemize*}
+The \field{additional_para} is fixed to 72 bytes in length, it contains a
+virtio_crypto_cipher_data_req_stateless structure or a virtio_crypto_alg_chain_data_req_stateless
+structure and the data of the unused part (if has) will be ingored.
+\end{itemize*}
+
+\drivernormative{\paragraph}{Symmetric algorithms Operation}{Device Types / Crypto Device / Device Operation / Symmetric algorithms Operation}
+
+\begin{itemize*}
+\item If the driver uses the session mode, then the driver MUST set \field{session_id}
+    in struct virtio_crypto_op_header to a valid value assigned by the device when the
+	session was created.
+\item If the VIRTIO_CRYPTO_F_MUX_MODE feature bit is negotiated, the driver MUST use
+    struct virtio_crypto_op_data_req_mux to wrap crypto requests. Otherwise, the driver
+	MUST use struct virtio_crypto_op_data_req.
+\item If the VIRTIO_CRYPTO_F_CIPHER_STATELESS_MODE feature bit is negotiated, 1) if the
+    driver uses the stateless mode, then the driver MUST set the \field{flag} field in
+	struct virtio_crypto_op_header to VIRTIO_CRYPTO_FLAG_STATELESS_MODE and MUST set the
+	fields in struct virtio_crypto_cipher_para_stateless.sess_para or struct
+	virtio_crypto_alg_chain_data_para_stateless.sess_para, 2) if the driver uses the
+	session mode, then the driver MUST set the \field{flag} field in struct
+	virtio_crypto_op_header to VIRTIO_CRYPTO_FLAG_SESSION_MODE.
+\item The driver MUST set the \field{opcode} field in struct virtio_crypto_op_header
+    to VIRTIO_CRYPTO_CIPHER_ENCRYPT or VIRTIO_CRYPTO_CIPHER_DECRYPT.
+\item The driver MUST specify the fields of struct virtio_crypto_cipher_data_req in
+    struct virtio_crypto_sym_data_req if the request is based on VIRTIO_CRYPTO_SYM_OP_CIPHER.
+\item The driver MUST specify the fields of both struct virtio_crypto_cipher_data_req
+    and struct virtio_crypto_mac_data_req in struct virtio_crypto_sym_data_req if the request
+	is of the VIRTIO_CRYPTO_SYM_OP_ALGORITHM_CHAINING type and in the VIRTIO_CRYPTO_SYM_HASH_MODE_AUTH mode.
+\end{itemize*}
+
+\devicenormative{\paragraph}{Symmetric algorithms Operation}{Device Types / Crypto Device / Device Operation / Symmetric algorithms Operation}
+
+\begin{itemize*}
+\item If the VIRTIO_CRYPTO_F_MUX_MODE feature bit is negotiated, the device MUST parse
+    the struct virtio_crypto_op_data_req_mux for crypto requests. Otherwise, the device
+	MUST parse the struct virtio_crypto_op_data_req.
+\item If the VIRTIO_CRYPTO_F_CIPHER_STATELESS_MODE feature bit is negotiated, the device
+    MUST parse \field{flag} field in struct virtio_crypto_op_header in order to decide
+	which mode the driver uses.
+\item The device MUST parse the virtio_crypto_sym_data_req based on the \field{opcode}
+    field in general header.
+\item The device SHOULD only parse fields of struct virtio_crypto_cipher_data_req in
+    struct virtio_crypto_sym_data_req if the request is VIRTIO_CRYPTO_SYM_OP_CIPHER type.
+\item The device MUST parse fields of both struct virtio_crypto_cipher_data_req and
+    struct virtio_crypto_mac_data_req in struct virtio_crypto_sym_data_req if the request
+	is of the VIRTIO_CRYPTO_SYM_OP_ALGORITHM_CHAINING operation type and in the
+	VIRTIO_CRYPTO_SYM_HASH_MODE_AUTH mode.
+\item The device MUST copy the result of cryptographic operation in the dst_data[] in
+    both plain CIPHER mode and algorithms chain mode.
+\item The device MUST check the \field{para}.\field{add_len} is bigger than 0 before
+    parse the additional authenticated data in plain algorithms chain mode.
+\item The device MUST copy the result of HASH/MAC operation in the hash_result[] is
+    of the VIRTIO_CRYPTO_SYM_OP_ALGORITHM_CHAINING type.
+\item The device MUST set the \field{status} field in struct virtio_crypto_inhdr to
+    one of the following values of enum VIRTIO_CRYPTO_STATUS:
+\begin{itemize*}
+\item VIRTIO_CRYPTO_OK if the operation success.
+\item VIRTIO_CRYPTO_NOTSUPP if the requested algorithm or operation is unsupported.
+\item VIRTIO_CRYPTO_INVSESS if the session ID is invalid in session mode.
+\item VIRTIO_CRYPTO_ERR if failure not mentioned above occurs.
+\end{itemize*}
+\end{itemize*}
+
+\subsubsection{AEAD Service Operation}\label{sec:Device Types / Crypto Device / Device Operation / AEAD Service Operation}
+
+Session mode requests of symmetric algorithm are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_aead_para {
+    /*
+     * Byte Length of valid IV data.
+     *
+     * For GCM mode, this is either 12 (for 96-bit IVs) or 16, in which
+     *   case iv points to J0.
+     * For CCM mode, this is the length of the nonce, which can be in the
+     *   range 7 to 13 inclusive.
+     */
+    le32 iv_len;
+    /* length of additional auth data */
+    le32 aad_len;
+    /* length of source data */
+    le32 src_data_len;
+    /* length of dst data, this should be at least src_data_len + tag_len */
+    le32 dst_data_len;
+    /* Authentication tag length */
+    le32 tag_len;
+    le32 reserved;
+};
+
+struct virtio_crypto_aead_data_req {
+    /* Device-readable part */
+    struct virtio_crypto_aead_para para;
+    /*
+     * Initialization Vector data.
+     *
+     * For GCM mode, this is either the IV (if the length is 96 bits) or J0
+     *   (for other sizes), where J0 is as defined by NIST SP800-38D.
+     *   Regardless of the IV length, a full 16 bytes needs to be allocated.
+     * For CCM mode, the first byte is reserved, and the nonce should be
+     *   written starting at &iv[1] (to allow space for the implementation
+     *   to write in the flags in the first byte).  Note that a full 16 bytes
+     *   should be allocated, even though the iv_len field will have
+     *   a value less than this.
+     *
+     * The IV will be updated after every partial cryptographic operation.
+     */
+    u8 iv[iv_len];
+    /* Source data */
+    u8 src_data[src_data_len];
+    /* Additional authenticated data if exists */
+    u8 aad[aad_len];
+
+    /* Device-writable part */
+    /* Pointer to output data */
+    u8 dst_data[dst_data_len];
+
+    struct virtio_crypto_inhdr inhdr;
+};
+\end{lstlisting}
+
+Each data request uses virtio_crypto_aead_data_req structure to store information
+used to run the AEAD operations.
+
+The information includes the hash parameters stored in \field{para}, output data
+and input data. In the first virtio_crypto_aead_para structure, \field{iv_len}
+specifies the length of the initialization vector. \field{tag_len} specifies the
+length of the authentication tag; \field{aad_len} specifies the length of additional
+authentication data, \field{src_data_len} specifies the length of the source data;
+\field{dst_data_len} specifies the length of the destination data, which is at least
+\field{src_data_len} + \field{tag_len}.
+
+The output data here includes the IV/Counter data, source data and additional
+authenticated data if exists. The input data includes both destination data used
+to save the results of the AEAD operations. \field{inhdr} stores the status of
+executing the AEAD operations.
+
+Stateless mode AEAD service requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_aead_para_stateless {
+    struct {
+        /* See VIRTIO_CRYPTO_AEAD_* above */
+        le32 algo;
+        /* length of key */
+        le32 key_len;
+        /* encrypt or decrypt, See above VIRTIO_CRYPTO_OP_* */
+        le32 op;
+    } sess_para;
+
+    /* Byte Length of valid IV data. */
+    le32 iv_len;
+    /* Authentication tag length */
+    le32 tag_len;
+    /* length of additional auth data */
+    le32 aad_len;
+    /* length of source data */
+    le32 src_data_len;
+    /* length of dst data, this should be at least src_data_len + tag_len */
+    le32 dst_data_len;
+};
+
+struct virtio_crypto_aead_data_req_stateless {
+    /* Device-readable part */
+    struct virtio_crypto_aead_para_stateless para;
+    /* The cipher key */
+    u8 key[key_len];
+    /* Initialization Vector data. */
+    u8 iv[iv_len];
+    /* Source data */
+    u8 src_data[src_data_len];
+    /* Additional authenticated data if exists */
+    u8 aad[aad_len];
+
+    /* Device-writable part */
+    /* Pointer to output data */
+    u8 dst_data[dst_data_len];
+
+    struct virtio_crypto_inhdr inhdr;
+};
+\end{lstlisting}
+
+\drivernormative{\paragraph}{AEAD Service Operation}{Device Types / Crypto Device / Device Operation / AEAD Service Operation}
+
+\begin{itemize*}
+\item If the driver uses the session mode, then the driver MUST set
+    \field{session_id} in struct virtio_crypto_op_header to a valid value assigned
+	by the device when the session was created.
+\item If the VIRTIO_CRYPTO_F_MUX_MODE feature bit is negotiated, the driver MUST
+    use struct virtio_crypto_op_data_req_mux to wrap crypto requests. Otherwise,
+	the driver MUST use struct virtio_crypto_op_data_req.
+\item If the VIRTIO_CRYPTO_F_AEAD_STATELESS_MODE feature bit is negotiated, 1) if
+    the driver uses the stateless mode, then the driver MUST set the \field{flag}
+	field in struct virtio_crypto_op_header to VIRTIO_CRYPTO_FLAG_STATELESS_MODE
+	and MUST set the fields in struct virtio_crypto_aead_para_stateless.sess_para,
+	2) if the driver uses the session mode, then the driver MUST set the \field{flag}
+	field in struct virtio_crypto_op_header to VIRTIO_CRYPTO_FLAG_SESSION_MODE.
+\item The driver MUST set the \field{opcode} field in struct virtio_crypto_op_header
+    to VIRTIO_CRYPTO_AEAD_ENCRYPT or VIRTIO_CRYPTO_AEAD_DECRYPT.
+\end{itemize*}
+
+\devicenormative{\paragraph}{AEAD Service Operation}{Device Types / Crypto Device / Device Operation / AEAD Service Operation}
+
+\begin{itemize*}
+\item If the VIRTIO_CRYPTO_F_MUX_MODE feature bit is negotiated, the device MUST
+    parse the struct virtio_crypto_op_data_req_mux for crypto requests. Otherwise,
+	the device MUST parse the struct virtio_crypto_op_data_req.
+\item If the VIRTIO_CRYPTO_F_AEAD_STATELESS_MODE feature bit is negotiated, the
+    device MUST parse the virtio_crypto_aead_data_req based on the \field{opcode}
+	field in general header.
+\item The device MUST copy the result of cryptographic operation in the dst_data[].
+\item The device MUST copy the authentication tag in the dst_data[] offset the cipher result.
+\item The device MUST set the \field{status} field in struct virtio_crypto_inhdr to
+    one of the following values of enum VIRTIO_CRYPTO_STATUS:
+\item When the \field{opcode} field is VIRTIO_CRYPTO_AEAD_DECRYPT, the device MUST
+    verify and return the verification result to the driver.
+\begin{itemize*}
+\item VIRTIO_CRYPTO_OK if the operation success.
+\item VIRTIO_CRYPTO_NOTSUPP if the requested algorithm or operation is unsupported.
+\item VIRTIO_CRYPTO_BADMSG if the verification result is incorrect.
+\item VIRTIO_CRYPTO_INVSESS if the session ID invalid when in session mode.
+\item VIRTIO_CRYPTO_ERR if any failure not mentioned above occurs.
+\end{itemize*}
+\end{itemize*}