[v22,1/2] virtio-crypto: Add virtio crypto device specification

Message ID 1512545840-10256-2-git-send-email-longpeng2@huawei.com
State New
Headers show
Series
  • virtio-crypto: virtio crypto device specification
Related show

Commit Message

Longpeng (Mike) Dec. 6, 2017, 7:37 a.m.
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: Zhoujian <jianjay.zhou@huawei.com>
Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
---
 acknowledgements.tex |    4 +
 content.tex          |    2 +
 virtio-crypto.tex    | 1510 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1516 insertions(+)
 create mode 100644 virtio-crypto.tex

Comments

Halil Pasic Dec. 6, 2017, 11:01 a.m. | #1
On 12/06/2017 08:37 AM, Longpeng(Mike) wrote:
> +\field{outcome_len} is the size of struct virtio_crypto_session_input or
> +ZERO for the session-destroy operation.

This ain't correct. It should have been something like virtio_crypto_destroy_session_input.

> +
> +
> +\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 write only portion */
> +    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_flf {
> +    /* Device read only portion */
> +    le64  session_id;
> +    /* Device write only portion */

This is the device writable portion and thus what we cal op_outcome above.
So it should have been
};


struct virtio_crypto_destroy_session_input {
> +    le32  status;
> +    le32  padding;
> +};

If we aren't consistent about it the dividing into parts (like op specific
fixed and variable length (output) fields, operation outcome (input))
isn't really helpful.


Regards,
Halil
> +\end{lstlisting}
Gonglei (Arei) Dec. 7, 2017, 7:59 a.m. | #2
> 

> On 12/06/2017 08:37 AM, Longpeng(Mike) wrote:

> > +\field{outcome_len} is the size of struct virtio_crypto_session_input or

> > +ZERO for the session-destroy operation.

> 

> This ain't correct. It should have been something like

> virtio_crypto_destroy_session_input.

> 

Right, will fix it.

> > +

> > +

> > +\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 write only portion */

> > +    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_flf {

> > +    /* Device read only portion */

> > +    le64  session_id;

> > +    /* Device write only portion */

> 

> This is the device writable portion and thus what we cal op_outcome above.

> So it should have been

> };

> 

> 

> struct virtio_crypto_destroy_session_input {

> > +    le32  status;

> > +    le32  padding;

> > +};

> 

> If we aren't consistent about it the dividing into parts (like op specific

> fixed and variable length (output) fields, operation outcome (input))

> isn't really helpful.

> 

It's ok to us, we can do it. Any other comments?

Thanks,
-Gonglei
Longpeng (Mike) Dec. 11, 2017, 12:56 p.m. | #3
On 2017/12/6 19:01, Halil Pasic wrote:

> 
> 
> On 12/06/2017 08:37 AM, Longpeng(Mike) wrote:
>> +\field{outcome_len} is the size of struct virtio_crypto_session_input or
>> +ZERO for the session-destroy operation.
> 
> This ain't correct. It should have been something like virtio_crypto_destroy_session_input.
> 

Hi Halil,

I already fixed this just now.
Do you have any other comments on v22 ? I'll send v23 tomorrow if no. :)
Halil Pasic Dec. 11, 2017, 1:54 p.m. | #4
On 12/11/2017 01:56 PM, Longpeng (Mike) wrote:
> 
> 
> On 2017/12/6 19:01, Halil Pasic wrote:
> 
>>
>>
>> On 12/06/2017 08:37 AM, Longpeng(Mike) wrote:
>>> +\field{outcome_len} is the size of struct virtio_crypto_session_input or
>>> +ZERO for the session-destroy operation.
>>
>> This ain't correct. It should have been something like virtio_crypto_destroy_session_input.
>>
> 
> Hi Halil,
> 
> I already fixed this just now.
> Do you have any other comments on v22 ? I'll send v23 tomorrow if no. :)
> 

Did not read the rest of the document. I'm not in the middle of something,
but I wanted to read the operation part these days. I guess, you prefer
sending out v23 over waiting, so I guess I will wait for v23 then.

Some general questions/remarks before you spin v23:

* I'm not convinced about this 'header' and 'extra parameters' terminology.
Please see https://en.wikipedia.org/wiki/Header_(computing) for header.
I don't think it's fitting for the _flf structs. 
Same about the 'extra'. Please see  https://www.merriam-webster.com/dictionary/extra
(a : more than is due, usual, or necessary : additional) the things in
_vlf aren't extra at all. Do you intend to stick with is terminology?
If yes why? Please explain how should I read/understand it so that it makes
sense!

* Do we want/need to specify any alignment requirement for the
stuff in guest storage (for instance the _flf fields) or be explicit
about no alignment should be assumed (e.g virtio_crypto_mac_create_session_flf.algo
ain't necessarily aligned (in guest memory) as required by uint32_t)?

* I assume one request is supposed to correspond to one descriptor chain.
Right? If yes, could you tell me, where is this expressed in the spec.

Halil
Michael S. Tsirkin Dec. 11, 2017, 2:09 p.m. | #5
On Mon, Dec 11, 2017 at 02:54:25PM +0100, Halil Pasic wrote:
> * I assume one request is supposed to correspond to one descriptor chain.
> Right? If yes, could you tell me, where is this expressed in the spec.
> 
> Halil

That's always the default for all virtio devices, exceptions have to
be noted in spec.
Halil Pasic Dec. 11, 2017, 3:41 p.m. | #6
On 12/11/2017 03:09 PM, Michael S. Tsirkin wrote:
> On Mon, Dec 11, 2017 at 02:54:25PM +0100, Halil Pasic wrote:
>> * I assume one request is supposed to correspond to one descriptor chain.
>> Right? If yes, could you tell me, where is this expressed in the spec.
>>
>> Halil
> 
> That's always the default for all virtio devices, exceptions have to
> be noted in spec.
> 

Grew to think this myself. But I could not derive it form the virtio spec.
Could you give me a pointer or a quote that _specifies_ that that's always
the default, and that exceptions have to be noted in the spec (I guess
in the corresponding device specific normative section)?

What I've found (maybe) showing in this direction is:

"""
2.4.4 Message Framing

The framing of messages with descriptors is independent of the contents of the buffers. For example, a network transmit buffer consists of a 12 byte header followed by the network packet. This could be most simply placed in the descriptor table as a 12 byte output descriptor followed by a 1514 byte output descriptor, but it could also consist of a single 1526 byte output descriptor in the case where the header and packet are adjacent, or even three or more descriptors (possibly with loss of efficiency in that case).

Note that, some device implementations have large-but-reasonable restrictions on total descriptor size (such as based on IOV_MAX in the host OS). This has not been a problem in practice: little sympathy will be given to drivers which create unreasonably-sized descriptors such as by dividing a network packet into 1500 single-byte descriptors!
"""

This however talks about buffers and messages which (seem to be used as
synonyms here BTW), and about how no assumptions should be made about
how many descriptors are used in the descriptor chain (to transfer
the same in guest memory maximal buffer elements -- maximal in a sense
that no guest physically contiguous piece of memory is represented by
two adjacent elements).

Most of the devices don't talk about messages (but rather specify
requests). So it's hard to relate the requests/packets to messages
which are framed as buffers.

I find the whole terminology a bit hard to understand (and sometimes
ambiguous).

Please help me understand this aspect of the specification.

Regards,
Halil

Patch

diff --git a/acknowledgements.tex b/acknowledgements.tex
index 2d893d9..cdde247 100644
--- a/acknowledgements.tex
+++ b/acknowledgements.tex
@@ -16,10 +16,13 @@  Daniel Kiper,	Oracle	\newline
 Geoff Brown,	Machine-to-Machine Intelligence (M2MI) Corporation	\newline
 Gershon Janssen,	Individual Member	\newline
 James Bottomley,	Parallels IP Holdings GmbH	\newline
+Jian Zhou,	Huawei	\newline
+Lei Gong,	Huawei	\newline
 Luiz Capitulino,	Red Hat	\newline
 Michael S. Tsirkin,	Red Hat	\newline
 Paolo Bonzini,	Red Hat	\newline
 Pawel Moll,	ARM \newline
+Peng Long,	Huawei	\newline
 Richard Sohn,	Alcatel-Lucent \newline
 Rusty Russell,	IBM	\newline
 Sasha Levin,	Oracle	\newline
@@ -38,6 +41,7 @@  Brian Foley,  ARM \newline
 David Alan Gilbert, Red Hat \newline
 Fam Zheng, Red Hat	\newline
 Gerd Hoffmann, Red Hat	\newline
+Halil Pasic,	IBM	\newline
 Jason Wang, Red Hat \newline
 Laura Novich, Red Hat	\newline
 Patrick Durusau,	Technical Advisory Board, OASIS	\newline
diff --git a/content.tex b/content.tex
index c840588..d1d3b09 100644
--- a/content.tex
+++ b/content.tex
@@ -5819,6 +5819,8 @@  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 these device-independent feature bits defined:
diff --git a/virtio-crypto.tex b/virtio-crypto.tex
new file mode 100644
index 0000000..7e66898
--- /dev/null
+++ b/virtio-crypto.tex
@@ -0,0 +1,1510 @@ 
+\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.
+
+If VIRTIO_CRYPTO_F_MUX_MODE is negotiated 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 four parts:
+\begin{lstlisting}
+struct virtio_crypto_op_ctrl_req {
+    /* Device read only portion */
+
+    struct virtio_crypto_ctrl_header header;
+
+#define VIRTIO_CRYPTO_CTRLQ_OP_SPEC_HDR_NONMUX 56
+    /* fixed length fields, opcode specific */
+    u8 op_flf[flf_len];
+
+    /* variable length fields, opcode specific */
+    u8 op_vlf[vlf_len];
+
+    /* Device write only portion */
+
+    /* op result or completion status */
+    u8 op_outcome[outcome_len];
+};
+\end{lstlisting}
+
+\field{header} is a general header (see above).
+
+\field{op_flf} is the opcode (in \field{header}) specific header with fixed
+length.
+
+\field{flf_len} depends on the VIRTIO_CRYPTO_F_MUX_MODE feature bit (see below).
+
+\field{op_vlf} is the opcode (in \field{header}) specific extra payloads with
+variable length.
+
+\field{vlf_len} is the size of the specific structure used.
+\begin{note}
+The \field{vlf_len} of session-destroy operation and the hash-session-create
+operation is ZERO.
+\end{note}
+
+\begin{itemize*}
+\item If the the opcode (in \field{header}) is VIRTIO_CRYPTO_CIPHER_CREATE_SESSION
+    then \field{op_flf} is struct virtio_crypto_sym_create_session_flf if
+    VIRTIO_CRYPTO_F_MUX_MODE is negotiated and struct virtio_crypto_sym_create_session_flf if
+    padded to 56 bytes if NOT negotiated, and \field{op_vlf} is struct
+    virtio_crypto_sym_create_session_vlf.
+\item If the the opcode (in \field{header}) is VIRTIO_CRYPTO_HASH_CREATE_SESSION
+    then \field{op_flf} is struct virtio_crypto_hash_create_session_flf if
+    VIRTIO_CRYPTO_F_MUX_MODE is negotiated and struct virtio_crypto_hash_create_session_flf if
+    padded to 56 bytes if NOT negotiated.
+\item If the the opcode (in \field{header}) is VIRTIO_CRYPTO_MAC_CREATE_SESSION
+    then \field{op_flf} is struct virtio_crypto_mac_create_session_flf if
+    VIRTIO_CRYPTO_F_MUX_MODE is negotiated and struct virtio_crypto_mac_create_session_flf if
+    padded to 56 bytes if NOT negotiated, and \field{op_vlf} is struct
+    virtio_crypto_mac_create_session_vlf.
+\end{itemize*}
+\item If the the opcode (in \field{header}) is VIRTIO_CRYPTO_AEAD_CREATE_SESSION
+    then \field{op_flf} is struct virtio_crypto_aead_create_session_flf if
+    VIRTIO_CRYPTO_F_MUX_MODE is negotiated and struct virtio_crypto_aead_create_session_flf if
+    padded to 56 bytes if NOT negotiated, and \field{op_vlf} is struct
+    virtio_crypto_aead_create_session_vlf.
+\item If the the opcode (in \field{header}) is VIRTIO_CRYPTO_CIPHER_DESTROY_SESSION
+    or VIRTIO_CRYPTO_HASH_DESTROY_SESSION or VIRTIO_CRYPTO_MAC_DESTROY_SESSION or
+    VIRTIO_CRYPTO_AEAD_DESTROY_SESSION then \field{op_flf} is struct
+    virtio_crypto_destroy_session_flf if VIRTIO_CRYPTO_F_MUX_MODE is negotiated and
+    struct virtio_crypto_destroy_session_flf if padded to 56 bytes if NOT negotiated.
+\end{itemize*}
+
+\field{op_outcome} stores the result of operation, it must be struct
+virtio_crypto_session_input if it's indispensable.
+
+\field{outcome_len} is the size of struct virtio_crypto_session_input or
+ZERO for the session-destroy operation.
+
+
+\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 write only portion */
+    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_flf {
+    /* Device read only portion */
+    le64  session_id;
+    /* Device write only portion */
+    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}
+
+The fixed-length paramenters of HASH session requests is as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_hash_create_session_flf {
+    /* Device read only portion */
+
+    /* See VIRTIO_CRYPTO_HASH_* above */
+    le32 algo;
+    /* hash result length */
+    le32 hash_result_len;
+};
+\end{lstlisting}
+
+
+\subparagraph{Session operation: MAC session}\label{sec:Device Types / Crypto Device / Device
+Operation / Control Virtqueue / Session operation / Session operation: MAC session}
+
+The fixed-length and the variable-length parameters of MAC session requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_mac_create_session_flf {
+    /* Device read only portion */
+
+    /* 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_vlf {
+    /* Device read only portion */
+
+    /* The authenticated key */
+    u8 auth_key[auth_key_len];
+};
+\end{lstlisting}
+
+The length of \field{auth_key} is specified in \field{auth_key_len} in the struct
+virtio_crypto_mac_create_session_flf.
+
+
+\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 could be the CIPHER algorithms request
+or the chain algorithms (chaining CIPHER and HASH/MAC) request.
+
+The fixed-length and the variable-length parameters of CIPHER session requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_cipher_session_flf {
+    /* Device read only portion */
+
+    /* 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_vlf {
+    /* Device read only portion */
+
+    /* The cipher key */
+    u8 cipher_key[keylen];
+};
+\end{lstlisting}
+
+The length of \field{cipher_key} is specified in \field{keylen} in the struct
+virtio_crypto_cipher_session_flf.
+
+The fixed-length and the variable-length parameters of Chain session requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_alg_chain_session_flf {
+    /* Device read only portion */
+
+#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_flf cipher_hdr;
+
+#define VIRTIO_CRYPTO_ALG_CHAIN_SESS_OP_SPEC_HDR_SIZE  16
+    /* fixed length fields, algo specific */
+    u8 algo_flf[VIRTIO_CRYPTO_ALG_CHAIN_SESS_OP_SPEC_HDR_SIZE];
+
+    /* length of the additional authenticated data (AAD) in bytes */
+    le32 aad_len;
+    le32 padding;
+};
+
+struct virtio_crypto_alg_chain_session_vlf {
+    /* Device read only portion */
+
+    /* The cipher key */
+    u8 cipher_key[keylen];
+    /* The authenticated key */
+    u8 auth_key[auth_key_len];
+};
+\end{lstlisting}
+
+\field{hash_mode} decides the type used by \field{algo_flf}.
+
+\field{algo_flf} is fixed to 16 bytes and MUST contains or be one of
+the following types:
+\begin{itemize*}
+\item struct virtio_crypto_hash_create_session_flf
+\item struct virtio_crypto_mac_create_session_flf
+\end{itemize*}
+The data of unused part (if has) in \field{algo_flf} will be ignored.
+
+The length of \field{cipher_key} is specified in \field{keylen} in \field{cipher_hdr}.
+
+The length of \field{auth_key} is specified in \field{auth_key_len} in struct
+virtio_crypto_mac_create_session_flf.
+
+The fixed-length parameters of Symmetric session requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_sym_create_session_flf {
+    /* Device read only portion */
+
+#define VIRTIO_CRYPTO_SYM_SESS_OP_SPEC_HDR_SIZE  48
+    /* fixed length fields, opcode specific */
+    u8 op_flf[VIRTIO_CRYPTO_SYM_SESS_OP_SPEC_HDR_SIZE];
+
+/* 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}
+
+\field{op_flf} is fixed to 48 bytes, MUST contains or be one of
+the following types:
+\begin{itemize*}
+\item struct virtio_crypto_cipher_session_flf
+\item struct virtio_crypto_alg_chain_session_flf
+\end{itemize*}
+The data of unused part (if has) in \field{op_flf} will be ignored.
+
+\field{op_type} decides the type used by \field{op_flf}.
+
+The variable-length parameters of Symmetric session requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_sym_create_session_vlf {
+    /* Device read only portion */
+    /* variable length fields, opcode specific */
+    u8 op_vlf[vlf_len];
+};
+\end{lstlisting}
+
+\field{op_vlf} MUST contains or be one of the following types:
+\begin{itemize*}
+\item struct virtio_crypto_cipher_session_vlf
+\item struct virtio_crypto_alg_chain_session_vlf
+\end{itemize*}
+
+\field{op_type} in struct virtio_crypto_sym_create_session_flf decides the
+type used by \field{op_vlf}.
+
+\field{vlf_len} is the size of the specific structure used.
+
+
+\subparagraph{Session operation: AEAD session}\label{sec:Device Types / Crypto Device / Device
+Operation / Control Virtqueue / Session operation / Session operation: AEAD session}
+
+The fixed-length and the variable-length parameters of AEAD session requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_aead_create_session_flf {
+    /* Device read only portion */
+
+    /* 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_vlf {
+    /* Device read only portion */
+    u8 key[key_len];
+};
+\end{lstlisting}
+
+The length of \field{key} is specified in \field{key_len} in struct
+virtio_crypto_aead_create_session_flf.
+
+
+\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 \field{opcode} field based on service type: CIPHER, HASH, MAC, or AEAD.
+\item The driver MUST set the control general header, the opcode specific header,
+    the opcode specific extra parameters and the opcode specific outcome buffer in turn.
+    See \ref{sec:Device Types / Crypto Device / Device Operation / Control Virtqueue}.
+\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 opcode specific structure according to the
+    \field{opcode} in the control general header.
+\item The device MUST extract extra parameters according to the structures used.
+\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 four parts:
+\begin{lstlisting}
+struct virtio_crypto_op_data_req {
+    /* Device read only portion */
+
+    struct virtio_crypto_op_header header;
+
+#define VIRTIO_CRYPTO_DATAQ_OP_SPEC_HDR_NONMUX 48
+    /* fixed length fields, opcode specific */
+    u8 op_flf[flf_len];
+
+    /* Device read && write portion */
+    /* variable length fields, opcode specific */
+    u8 op_vlf[vlf_len];
+
+    /* Device write only portion */
+    struct virtio_crypto_inhdr inhdr;
+};
+\end{lstlisting}
+
+\field{header} is a general header (see above).
+
+\field{op_flf} is the opcode (in \field{header}) specific header.
+
+\field{flf_len} depends on the VIRTIO_CRYPTO_F_MUX_MODE feature bit
+(see below).
+
+\field{op_vlf} is the opcode (in \field{header}) specific parameters.
+
+\field{vlf_len} is the size of the specific structure used.
+
+\begin{itemize*}
+\item If the the opcode (in \field{header}) is VIRTIO_CRYPTO_CIPHER_ENCRYPT
+    or VIRTIO_CRYPTO_CIPHER_DECRYPT then:
+    \begin{itemize*}
+	\item If VIRTIO_CRYPTO_F_CIPHER_STATELESS_MODE is negotiated, \field{op_flf} is
+        struct virtio_crypto_sym_data_flf_stateless, and \field{op_vlf} is struct
+        virtio_crypto_sym_data_vlf_stateless.
+    \item If VIRTIO_CRYPTO_F_CIPHER_STATELESS_MODE is NOT negotiated, \field{op_flf}
+        is struct virtio_crypto_sym_data_flf if VIRTIO_CRYPTO_F_MUX_MODE is negotiated
+        and struct virtio_crypto_sym_data_flf if padded to 48 bytes if NOT negotiated,
+        and \field{op_vlf} is struct virtio_crypto_sym_data_vlf.
+    \end{itemize*}
+\item If the the opcode (in \field{header}) is VIRTIO_CRYPTO_HASH:
+    \begin{itemize*}
+	\item If VIRTIO_CRYPTO_F_HASH_STATELESS_MODE is negotiated, \field{op_flf} is
+        struct virtio_crypto_hash_data_flf_stateless, and \field{op_vlf} is struct
+        virtio_crypto_hash_data_vlf_stateless.
+    \item If VIRTIO_CRYPTO_F_HASH_STATELESS_MODE is NOT negotiated, \field{op_flf}
+        is struct virtio_crypto_hash_data_flf if VIRTIO_CRYPTO_F_MUX_MODE is negotiated
+        and struct virtio_crypto_hash_data_flf if padded to 48 bytes if NOT negotiated,
+        and \field{op_vlf} is struct virtio_crypto_hash_data_vlf.
+\item If the the opcode (in \field{header}) is VIRTIO_CRYPTO_MAC:
+    \begin{itemize*}
+	\item If VIRTIO_CRYPTO_F_MAC_STATELESS_MODE is negotiated, \field{op_flf} is
+        struct virtio_crypto_mac_data_flf_stateless, and \field{op_vlf} is struct
+        virtio_crypto_mac_data_vlf_stateless.
+    \item If VIRTIO_CRYPTO_F_MAC_STATELESS_MODE is NOT negotiated, \field{op_flf}
+        is struct virtio_crypto_mac_data_flf if VIRTIO_CRYPTO_F_MUX_MODE is negotiated
+        and struct virtio_crypto_mac_data_flf if padded to 48 bytes if NOT negotiated,
+        and \field{op_vlf} is struct virtio_crypto_mac_data_vlf.
+\item If the the opcode (in \field{header}) is VIRTIO_CRYPTO_AEAD_ENCRYPT
+    or VIRTIO_CRYPTO_AEAD_DECRYPT then:
+    \begin{itemize*}
+	\item If VIRTIO_CRYPTO_F_AEAD_STATELESS_MODE is negotiated, \field{op_flf} is
+        struct virtio_crypto_aead_data_flf_stateless, and \field{op_vlf} is struct
+        virtio_crypto_aead_data_vlf_stateless.
+    \item If VIRTIO_CRYPTO_F_AEAD_STATELESS_MODE is NOT negotiated, \field{op_flf}
+        is struct virtio_crypto_aead_data_flf if VIRTIO_CRYPTO_F_MUX_MODE is negotiated
+        and struct virtio_crypto_aead_data_flf if padded to 48 bytes if NOT negotiated,
+        and \field{op_vlf} is struct virtio_crypto_aead_data_vlf.
+\end{itemize*}
+
+\field{inhdr} is a unified input header that used to return the status of
+the operations, 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_data_flf {
+    /* length of source data */
+    le32 src_data_len;
+    /* hash result length */
+    le32 hash_result_len;
+};
+
+struct virtio_crypto_hash_data_vlf {
+    /* Device read only portion */
+    /* Source data */
+    u8 src_data[src_data_len];
+
+    /* Device write only portion */
+    /* Hash result data */
+    u8 hash_result[hash_result_len];
+};
+\end{lstlisting}
+
+Each data request uses the virtio_crypto_hash_data_flf structure and the
+virtio_crypto_hash_data_vlfto structure to store information used to run the
+HASH operations.
+
+\field{src_data} is the source data that will be processed.
+\field{src_data_len} is the length of source data.
+\field{hash_result} is the result data and \field{hash_result_len} is the length
+of it.
+
+Stateless mode HASH service requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_hash_data_flf_stateless {
+    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_vlf_stateless {
+    /* Device read only portion */
+    /* Source data */
+    u8 src_data[src_data_len];
+
+    /* Device write only portion */
+    /* Hash result data */
+    u8 hash_result[hash_result_len];
+};
+\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_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_data_flf_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 The device MUST use the corresponding 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_data_flf {
+    struct virtio_crypto_hash_data_flf hdr;
+};
+
+struct virtio_crypto_mac_data_vlf {
+    /* Device read only portion */
+    /* Source data */
+    u8 src_data[src_data_len];
+
+    /* Device write only portion */
+    /* Hash result data */
+    u8 hash_result[hash_result_len];
+};
+\end{lstlisting}
+
+Each request uses the virtio_crypto_mac_data_flf structure and the
+virtio_crypto_mac_data_vlf structure to store information used to run the
+MAC operations.
+
+\field{src_data} is the source data that will be processed.
+\field{src_data_len} is the length of source data.
+\field{hash_result} is the result data and \field{hash_result_len} is the length
+of it.
+
+Stateless mode MAC service requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_mac_data_flf_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_vlf_stateless {
+    /* Device read only portion */
+    /* The authenticated key */
+    u8 auth_key[auth_key_len];
+    /* Source data */
+    u8 src_data[src_data_len];
+
+    /* Device write only portion */
+    /* Hash result data */
+    u8 hash_result[hash_result_len];
+};
+\end{lstlisting}
+
+\field{auth_key} is the authenticated key that will be used during the process.
+\field{auth_key_len} is the length of the key.
+
+\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_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_data_flf_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_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_data_flf {
+    /*
+     * 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_vlf {
+    /* Device read only portion */
+
+    /*
+     * 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 write only portion */
+    /* Destination data */
+    u8 dst_data[dst_data_len];
+};
+\end{lstlisting}
+
+Session mode requests of algorithm chaining are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_alg_chain_data_flf {
+    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_vlf {
+    /* Device read only portion */
+
+    /* 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 write only portion */
+
+    /* Destination data */
+    u8 dst_data[dst_data_len];
+    /* Hash result data */
+    u8 hash_result[hash_result_len];
+};
+\end{lstlisting}
+
+Session mode requests of symmetric algorithm are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_sym_data_flf {
+    /* Device read only portion */
+
+#define VIRTIO_CRYPTO_SYM_DATA_REQ_HDR_SIZE    40
+    u8 op_type_flf[VIRTIO_CRYPTO_SYM_DATA_REQ_HDR_SIZE];
+
+    /* See above VIRTIO_CRYPTO_SYM_OP_* */
+    le32 op_type;
+    le32 padding;
+};
+
+struct virtio_crypto_sym_data_vlf {
+    u8 op_type_vlf[sym_para_len];
+};
+\end{lstlisting}
+
+Each request uses the virtio_crypto_sym_data_flf structure and the
+virtio_crypto_sym_data_flf structure to store information used to run the
+CIPHER operations.
+
+\field{op_type_flf} is the \field{op_type} specific header, it MUST starts
+with or be one of the following structures:
+\begin{itemize*}
+\item struct virtio_crypto_cipher_data_flf
+\item struct virtio_crypto_alg_chain_data_flf
+\end{itemize*}
+
+The length of \field{op_type_flf} is fixed to 40 bytes, the data of unused
+part (if has) will be ingored.
+
+\field{op_type_vlf} is the \field{op_type} specific parameters, it MUST starts
+with or be one of the following structures:
+\begin{itemize*}
+\item struct virtio_crypto_cipher_data_vlf
+\item struct virtio_crypto_alg_chain_data_vlf
+\end{itemize*}
+
+\field{sym_para_len} is the size of the specific structure used.
+
+Stateless mode CIPHER service requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_cipher_data_flf_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_vlf_stateless {
+    /* Device read only portion */
+
+    /* 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 write only portion */
+    /* Destination data */
+    u8 dst_data[dst_data_len];
+};
+\end{lstlisting}
+
+Stateless mode requests of algorithm chaining are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_alg_chain_data_flf_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_vlf_stateless {
+    /* Device read only portion */
+
+    /* 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 write only portion */
+
+    /* Destination data */
+    u8 dst_data[dst_data_len];
+    /* Hash result data */
+    u8 hash_result[hash_result_len];
+};
+\end{lstlisting}
+
+Stateless mode requests of symmetric algorithm are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_sym_data_flf_stateless {
+    /* Device read only portion */
+#define VIRTIO_CRYPTO_SYM_DATE_REQ_HDR_STATELESS_SIZE    72
+    u8 op_type_flf[VIRTIO_CRYPTO_SYM_DATE_REQ_HDR_STATELESS_SIZE];
+
+    /* Device write only portion */
+    /* See above VIRTIO_CRYPTO_SYM_OP_* */
+    le32 op_type;
+};
+
+struct virtio_crypto_sym_data_vlf_stateless {
+    u8 op_type_vlf[sym_para_len];
+};
+\end{lstlisting}
+
+\field{op_type_flf} is the \field{op_type} specific header, it MUST starts
+with or be one of the following structures:
+\begin{itemize*}
+\item struct virtio_crypto_cipher_data_flf_stateless
+\item struct virtio_crypto_alg_chain_data_flf_stateless
+\end{itemize*}
+
+The length of \field{op_type_flf} is fixed to 72 bytes, the data of unused
+part (if has) will be ingored.
+
+\field{op_type_vlf} is the \field{op_type} specific parameters, it MUST starts
+with or be one of the following structures:
+\begin{itemize*}
+\item struct virtio_crypto_cipher_data_vlf_stateless
+\item struct virtio_crypto_alg_chain_data_vlf_stateless
+\end{itemize*}
+
+\field{sym_para_len} is the size of the specific structure used.
+
+\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_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_data_flf_stateless.sess_para or struct
+	virtio_crypto_alg_chain_data_flf_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_flf in
+    struct virtio_crypto_sym_data_flf and struct virtio_crypto_cipher_data_vlf in
+    struct virtio_crypto_sym_data_vlf if the request is based on VIRTIO_CRYPTO_SYM_OP_CIPHER.
+\item The driver MUST specify the fields of struct virtio_crypto_alg_chain_data_flf
+    in struct virtio_crypto_sym_data_flf and struct virtio_crypto_alg_chain_data_vlf
+    in struct virtio_crypto_sym_data_vlf if the request is of the VIRTIO_CRYPTO_SYM_OP_ALGORITHM_CHAINING
+    type.
+\end{itemize*}
+
+\devicenormative{\paragraph}{Symmetric algorithms Operation}{Device Types / Crypto Device / Device Operation / Symmetric algorithms Operation}
+
+\begin{itemize*}
+\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 MUST parse the fields of struct virtio_crypto_cipher_data_flf in
+    struct virtio_crypto_sym_data_flf and struct virtio_crypto_cipher_data_vlf in
+    struct virtio_crypto_sym_data_vlf if the request is based on VIRTIO_CRYPTO_SYM_OP_CIPHER.
+\item The device MUST parse the fields of struct virtio_crypto_alg_chain_data_flf
+    in struct virtio_crypto_sym_data_flf and struct virtio_crypto_alg_chain_data_vlf
+    in struct virtio_crypto_sym_data_vlf if the request is of the VIRTIO_CRYPTO_SYM_OP_ALGORITHM_CHAINING
+    type.
+\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_data_flf {
+    /*
+     * 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_vlf {
+    /* Device read only portion */
+
+    /*
+     * 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 write only portion */
+    /* Pointer to output data */
+    u8 dst_data[dst_data_len];
+};
+\end{lstlisting}
+
+Each request uses the virtio_crypto_aead_data_flf structure and the
+virtio_crypto_aead_data_flf structure to store information used to run the
+AEAD operations.
+
+Stateless mode AEAD service requests are as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_aead_data_flf_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_vlf_stateless {
+    /* Device read only portion */
+
+    /* 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 write only portion */
+    /* Pointer to output data */
+    u8 dst_data[dst_data_len];
+};
+\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_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_data_flf_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_AEAD_STATELESS_MODE feature bit is negotiated, the
+    device MUST parse the virtio_crypto_aead_data_vlf_stateless 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*}