Re: [Qemu-devel] [virtio-dev] [PATCH v16 1/2] virtio-crypto: Add virtio crypto device specification

[Halil Pasic]

On 01/18/2017 09:22 AM, Gonglei wrote:
> 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 <address@hidden>
> CC: Michael S. Tsirkin <address@hidden>
> CC: Cornelia Huck <address@hidden>
> CC: Stefan Hajnoczi <address@hidden>
> CC: Lingli Deng <address@hidden>
> CC: Jani Kokkonen <address@hidden>
> CC: Ola Liljedahl <address@hidden>
> CC: Varun Sethi <address@hidden>
> CC: Zeng Xin <address@hidden>
> CC: Keating Brian <address@hidden>
> CC: Ma Liang J <address@hidden>
> CC: Griffin John <address@hidden>
> CC: Mihai Claudiu Caraman <address@hidden>
> ---
>  content.tex       |    2 +
>  virtio-crypto.tex | 1245 
> +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 1247 insertions(+)
>  create mode 100644 virtio-crypto.tex
> 
> diff --git a/content.tex b/content.tex
> index 4b45678..ab75f78 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -5750,6 +5750,8 @@ 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..732cd30
> --- /dev/null
> +++ b/virtio-crypto.tex
> @@ -0,0 +1,1245 @@
> +\section{Crypto Device}\label{sec:Device Types / Crypto Device}
> +
> +The virtio crypto device is a virtual cryptography device as well as a kind 
> of
> +virtual hardware accelerator for virtual machines. The encryption and
> +decryption requests are placed in any of the data active queues and are 
> ultimately handled by the

Am I the only one having a problem with 'data active queues'?
I have objected on this before.

> +backend crypto accelerators. The second kind of queue is the control queue 
> used to create 
> +or destroy sessions for symmetric algorithms and will control some advanced
> +features in the future. The virtio crypto device provides the following 
> crypto
> +services: CIPHER, MAC, HASH, and AEAD.
> +
> +
> +\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}
> +
> +VIRTIO_CRYPTO_F_NON_SESSION_MODE (0) non-session mode is available.
> +VIRTIO_CRYPTO_F_CIPHER_NON_SESSION_MODE (1) non-session mode is available 
> for CIPHER service.
> +VIRTIO_CRYPTO_F_HASH_NON_SESSION_MODE (2) non-session mode is available for 
> HASH service.
> +VIRTIO_CRYPTO_F_MAC_NON_SESSION_MODE (3) non-session mode is available for 
> MAC service.
> +VIRTIO_CRYPTO_F_AEAD_NON_SESSION_MODE (4) non-session mode is available for 
> AEAD service.
> +

I'm not sure that "non-session" entirely correct grammatically. I would
prefer sessionless as alternatively proposed by Stefan, or even stateless.
I think stateless is the phrase most frequently used to describe what
we want to introduce -- that is basically response = f(request) and
not response = f(request, server_state) where the server_state is
a is determined by a series of previous interactions between the server
and the client).

> +\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_NON_SESSION_MODE] Requires 
> VIRTIO_CRYPTO_F_NON_SESSION_MODE.
> +\item[VIRTIO_CRYPTO_F_HASH_NON_SESSION_MODE] Requires 
> VIRTIO_CRYPTO_F_NON_SESSION_MODE.
> +\item[VIRTIO_CRYPTO_F_MAC_NON_SESSION_MODE] Requires 
> VIRTIO_CRYPTO_F_NON_SESSION_MODE.
> +\item[VIRTIO_CRYPTO_F_AEAD_NON_SESSION_MODE] Requires 
> VIRTIO_CRYPTO_F_NON_SESSION_MODE.
> +\end{description}
> +
> +\subsection{Device configuration layout}\label{sec:Device Types / Crypto 
> Device / Device configuration layout}
> +
> +The following driver-read-only configuration fields are defined:
> +
> +\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 */
> +    le32 max_cipher_key_len;
> +    /* Maximum length of authenticated key */
> +    le32 max_auth_key_len;
> +    le32 reserved;
> +    /* Maximum size of each crypto request's content */
> +    le64 max_size;
> +};
> +\end{lstlisting}
> +
> +The value of the \field{status} field is VIRTIO_CRYPTO_S_HW_READY or 
> ~VIRTIO_CRYPTO_S_HW_READY.

Not entirely happy with this. What you want to say is reserved
for future use, or? Would it make sense to have a general note
-- in a similar fashion like for 'sizes are in bytes' -- for
reserved for future use? 

One possible formulation would be:

"In this specification, unless explicitly stated otherwise,
fields and bits reserved for future use shall be zeroed out.
Both the a device or a driver device and the driver should
detect violations of this rule, and deny the requested
operation in an appropriate way if possible."
 

> +
> +\begin{lstlisting}
> +#define VIRTIO_CRYPTO_S_HW_READY  (1 << 0)
> +\end{lstlisting}
> +
> +The VIRTIO_CRYPTO_S_HW_READY flag is used to show whether the hardware is 
> ready to work or not.

I do not like hardware here.

> +
> +The following driver-read-only fields include \field{max_dataqueues}, which 
> specifies the

Why following?

> +maximum number of data virtqueues (dataq1\ldots dataqN), and 
> \field{crypto_services},
> +which indicates the crypto services the virtio crypto supports.
> +
> +The following 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 last driver-read-only fields specify detailed algorithms masks 
> +the device offers for corresponding services. The following CIPHER algorithms
> +are defined:

You do not establish an explicit relationship between the fields and the
macros for the flags. These are flags or? It seems quite common in the
spec to use _F_ in flag names. Would it be appropriate here?

> +
> +\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 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 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 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}
> +

Would it make sense to interleave the flag definition
with the struct virtio_crypto_config?

> +\begin{note}
> +Any other values are reserved for future use.

Are these flags or values? I do not think values is appropriate here.

> +\end{note}
> +

Some fields are missing here. This is inconsistent. Either
you should describe all or none (here).

> +\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 \field{status} based on the status of the 
> hardware-backed implementation.

What is a hardware-backend?

> +\item The device MUST accept and handle requests after \field{status} is set 
> to VIRTIO_CRYPTO_S_HW_READY.

Shouldn't this be the other way around (if VIRTIO_CRYPTO_S_HW_READY
then reject). Is a not well formed request or a backend failure considered?
What does handle mean? What should happen if requests are submitted
before VIRTIO_CRYPTO_S_HW_READY is set?

> +\item The device MUST set \field{crypto_services} based on the crypto 
> services the device offers.
> +\item The device MUST set detailed algorithms masks based on the 
> \field{crypto_services} field.
> +\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 ready \field{status} from the bottom bit of 
> status to check whether the hardware-backed
> +      implementation is ready or not, and the driver MUST reread it after 
> the device reset. 
> +\item The driver MUST NOT transmit any packets to the device if the ready 
> \field{status} 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 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 identify and initialize the control virtqueue.

But does not have to identify and initialize any data 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*}
> +
> +\devicenormative{\subsubsection}{Device Initialization}{Device Types / 
> Crypto Device / Device Initialization}
> +
> +\begin{itemize*}
> +\item The device MUST be configured with at least one accelerator which 
> executes backend crypto operations.

What does configured mean here? Is this initialization requirement.

> +\item The device MUST write the \field{crypto_services} field based on the 
> capacities of the backend accelerator.
> +\end{itemize*}
> +

How do 'Initialization' and 'Configuration Layout' requirements relate to
each-other.

> +\subsection{Device Operation}\label{sec:Device Types / Crypto Device / 
> Device Operation}
> +
> +Packets can be transmitted by placing them in both the controlq and dataq.
> +Packets consist of a general header and a service-specific request.

Are packets and requests synonyms?

> +Where 'general header' is for all crypto requests, and 'service specific 
> requests'

>From below it seems you have two types of 'general header', but up until this
point it seems there is a single definition. Of course, this does not
really matter.

> +are composed of operation parameter + output data + input data in general.
> +Operation parameters are algorithm-specific parameters, output data is the
> +data that should be utilized in operations, and input data is equal to
> +"operation result + result data".
> +
> +The device can support both session mode (See \ref{sec:Device Types / Crypto 
> Device / Device Operation / Control Virtqueue / Session operation}) and 
> non-session mode, for example,
> +As VIRTIO_CRYPTO_F_CIPHER_NON_SESSION_MODE feature bit is negotiated, the 
> driver can use non-session mode for CIPHER service, otherwise it can only use 
> session mode.

Grammar: Does not seem right to me. 'As' seems off and this could be two
sentences.


> +
> +\begin{note}
> +The basic unit of all data length the byte.
> +\end{note}
> +
> +The general header for controlq is as follows:
> +
> +\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;
> +    le32 algo;
> +    le32 flag;
> +    /* data virtqueue id */
> +    le32 queue_id;
> +};
> +\end{lstlisting}
> +
> +The general header of dataq:
> +
> +\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;
> +    /* session_id should be service-specific algorithms */
> +    le64 session_id;
> +#define VIRTIO_CRYPTO_FLAG_SESSION_MODE 1
> +#define VIRTIO_CRYPTO_FLAG_NON_SESSION_MODE 2

Use _F_ istead of _FLAG_? 

> +    /* control flag to control the request */
> +    le32 flag;
> +    le32 padding;
> +};
> +\end{lstlisting}
> +
> +The device can set the operation status as follows: VIRTIO_CRYPTO_OK: 
> success;
> +VIRTIO_CRYPTO_ERR: failure or device error; VIRTIO_CRYPTO_NOTSUPP: not 
> supported;
> +VIRTIO_CRYPTO_INVSESS: invalid session ID when executing crypto operations.
> +
> +\begin{lstlisting}
> +enum VIRITO_CRYPTO_STATUS {
> +    VIRTIO_CRYPTO_OK = 0,
> +    VIRTIO_CRYPTO_ERR = 1,
> +    VIRTIO_CRYPTO_BADMSG = 2,
> +    VIRTIO_CRYPTO_NOTSUPP = 3,
> +    VIRTIO_CRYPTO_INVSESS = 4,
> +    VIRTIO_CRYPTO_MAX
> +};
> +\end{lstlisting}
> +
> +\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 which handles the non-data plane operations, such as session

What is a 'non-data plane'?

> +operations (See \ref{sec:Device Types / Crypto Device / Device Operation / 
> Control Virtqueue / Session operation}).

Reviewed up until here. Depending on how things evolve will try to
review the rest too in the following days.

A question and a remark as a closing word:
* Are there already some kernel and qemu patches for this 'non-session' stuff?
* I think some proofreading (and eventually also touch-up) by a native speaker
would really benefit us. Sadly my grammar skills are very questionable, so
I can't help much. Nevertheless since it is a spec, I think we sould strive
for high standards in language usage too.