Add virtio rpmb device specification

Add virtio RPMB (Replay Protected Memory Block) device documentation to
spec.

Signed-off-by: Yang Huang <yang.huang@intel.com>
Reviewed-by: Bing Zhu <bing.zhu@intel.com>
Reviewed-by: Tomas Winkler <tomas.winkler@intel.com>
Fixes: https://github.com/oasis-tcs/virtio-spec/issues/53
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

4 files changed, 315 insertions, 1 deletions

diff --git a/conformance.tex b/conformance.tex
index 0ac58aa..50969e5 100644
--- a/conformance.tex
+++ b/conformance.tex
@@ -22,7 +22,7 @@ Conformance targets:
   \begin{itemize}
     \item Clause \ref{sec:Conformance / Device Conformance}.
     \item One of clauses \ref{sec:Conformance / Device Conformance / PCI Device Conformance}, \ref{sec:Conformance / Device Conformance / MMIO Device Conformance} or \ref{sec:Conformance / Device Conformance / Channel I/O Device Conformance}.
-    \item One of clauses \ref{sec:Conformance / Device Conformance / Network Device Conformance}, \ref{sec:Conformance / Device Conformance / Block Device Conformance}, \ref{sec:Conformance / Device Conformance / Console Device Conformance}, \ref{sec:Conformance / Device Conformance / Entropy Device Conformance}, \ref{sec:Conformance / Device Conformance / Traditional Memory Balloon Device Conformance}, \ref{sec:Conformance / Device Conformance / SCSI Host Device Conformance}, \ref{sec:Conformance / Device Conformance / Input Device Conformance}, \ref{sec:Conformance / Device Conformance / Crypto Device Conformance} or \ref{sec:Conformance / Device Conformance / Socket Device Conformance}.
+    \item One of clauses \ref{sec:Conformance / Device Conformance / Network Device Conformance}, \ref{sec:Conformance / Device Conformance / Block Device Conformance}, \ref{sec:Conformance / Device Conformance / Console Device Conformance}, \ref{sec:Conformance / Device Conformance / Entropy Device Conformance}, \ref{sec:Conformance / Device Conformance / Traditional Memory Balloon Device Conformance}, \ref{sec:Conformance / Device Conformance / SCSI Host Device Conformance}, \ref{sec:Conformance / Device Conformance / Input Device Conformance}, \ref{sec:Conformance / Device Conformance / Crypto Device Conformance}, \ref{sec:Conformance / Device Conformance / Socket Device Conformance} or \ref{sec:Conformance / Device Conformance / RPMB Device Conformance}.
     \item Clause \ref{sec:Conformance / Legacy Interface: Transitional Device and Transitional Driver Conformance}.
   \end{itemize}
 \end{description}
@@ -183,6 +183,14 @@ A socket driver MUST conform to the following normative statements:
 \item \ref{drivernormative:Device Types / Socket Device / Device Operation / Device Events}
 \end{itemize}
 
+\conformance{\subsection}{RPMB Driver Conformance}\label{sec:Conformance / Driver Conformance / RPMB Driver Conformance}
+
+A RPMB driver MUST conform to the following normative statements:
+
+\begin{itemize}
+\item \ref{drivernormative:Device Types / RPMB Device / Device Operation}
+\end{itemize}
+
 \conformance{\section}{Device Conformance}\label{sec:Conformance / Device Conformance}
 
 A device MUST conform to the following normative statements:
@@ -338,6 +346,20 @@ A socket device MUST conform to the following normative statements:
 \item \ref{devicenormative:Device Types / Socket Device / Device Operation / Receive and Transmit}
 \end{itemize}
 
+\conformance{\subsection}{RPMB Device Conformance}\label{sec:Conformance / Device Conformance / RPMB Device Conformance}
+
+An RPMB device MUST conform to the following normative statements:
+
+\begin{itemize}
+\item \ref{devicenormative:Device Types / RPMB Device / Device Initialization}
+\item \ref{devicenormative:Device Types / RPMB Device / Device Operation / Device Operation: Program Key}
+\item \ref{devicenormative:Device Types / RPMB Device / Device Operation / Device Operation: Get Write Counter}
+\item \ref{devicenormative:Device Types / RPMB Device / Device Operation / Device Operation: Data Write}
+\item \ref{devicenormative:Device Types / RPMB Device / Device Operation / Device Operation: Data Read}
+\item \ref{devicenormative:Device Types / RPMB Device / Device Operation / Device Operation: Result Read}
+\item \ref{devicenormative:Device Types / RPMB Device / Device Operation}
+\end{itemize}
+
 \conformance{\section}{Legacy Interface: Transitional Device and Transitional Driver Conformance}\label{sec:Conformance / Legacy Interface: Transitional Device and Transitional Driver Conformance}
 A conformant implementation MUST be either transitional or
 non-transitional, see \ref{intro:Legacy
diff --git a/content.tex b/content.tex
index 06bb4ca..cd321a1 100644
--- a/content.tex
+++ b/content.tex
@@ -5812,6 +5812,7 @@ descriptor for the \field{sense_len}, \field{residual},
 \input{virtio-crypto.tex}
 \input{virtio-vsock.tex}
 \input{virtio-fs.tex}
+\input{virtio-rpmb.tex}
 
 \chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits}
 
diff --git a/introduction.tex b/introduction.tex
index 40f16f8..33da3ec 100644
--- a/introduction.tex
+++ b/introduction.tex
@@ -63,6 +63,9 @@ Levels'', BCP 14, RFC 2119, March 1997. \newline\url{http://www.ietf.org/rfc/rfc
 	\phantomsection\label{intro:FUSE}\textbf{[FUSE]} &
 	Linux FUSE interface,
 	\newline\url{https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/uapi/linux/fuse.h}\\
+        \phantomsection\label{intro:eMMC}\textbf{[eMMC]} &
+        eMMC Electrical Standard (5.1), JESD84-B51,
+        \newline\url{http://www.jedec.org/sites/default/files/docs/JESD84-B51.pdf}\\
 
 \end{longtable}
 
diff --git a/virtio-rpmb.tex b/virtio-rpmb.tex
new file mode 100644
index 0000000..dfecc3c
--- /dev/null
+++ b/virtio-rpmb.tex
@@ -0,0 +1,288 @@
+\section{RPMB Device}\label{sec:Device Types / RPMB Device}
+
+virtio-rpmb is a virtio based RPMB (Replay Protected Memory Block)
+device. It is used as a tamper-resistant and anti-replay storage.
+The device is driven via requests including read, write, get write
+counter and program key, which are submitted via a request queue.
+This section relies on definitions from paragraph 6.6.22 of
+\hyperref[intro:eMMC]{eMMC}.
+\subsection{Device ID}\label{sec:Device Types / RPMB Device / Device ID}
+
+28
+
+\subsection{Virtqueues}\label{sec:Device Types / RPMB Device / Virtqueues}
+
+\begin{description}
+\item[0] requestq
+\end{description}
+
+\subsection{Feature bits}\label{sec:Device Types / RPMB Device / Feature bits}
+
+None.
+
+\subsection{Device configuration layout}\label{sec:Device Types / RPMB Device / Device configuration layout}
+
+All fields of this configuration are always available and read-only for the driver.
+
+\begin{lstlisting}
+struct virtio_rpmb_config {
+        u8 capacity;
+        u8 max_wr_cnt;
+        u8 max_rd_cnt;
+}
+\end{lstlisting}
+
+\begin{description}
+\item[\field{capacity}] is the capacity of the device (expressed in 128KB units).
+   The values MUST range between 0x00 and 0x80 inclusive.
+\item[\field{max_wr_cnt and max_rd_cnt}] are the maximum numbers of RPMB
+   block count (256B) that can be performed to device in one request. 0 implies
+   no limitation.
+\end{description}
+
+\devicenormative{\subsection}{Device Initialization}{Device Types / RPMB Device / Device Initialization}
+
+\begin{enumerate}
+\item The virtqueue is initialized.
+\item The device capacity MUST be initialized to a multiple of 128Kbytes and up to
+   16Mbytes.
+\end{enumerate}
+
+\subsection{Device Operation}\label{sec:Device Types / RPMB Device / Device Operation}
+
+The operation of a virtio RPMB device is driven by the requests placed on the virtqueue.
+  The type of request can be program key (VIRTIO_RPMB_REQ_PROGRAM_KEY),
+  get write counter (VIRTIO_RPMB_REQ_GET_WRITE_COUNTER),
+  write (VIRTIO_RPMB_REQ_DATA_WRITE), and read (VIRTIO_RPMB_REQ_DATA_READ).
+  A program key or write request can also combine with a
+  result read (VIRTIO_RPMB_REQ_RESULT_READ) for a returned result.
+
+\begin{lstlisting}
+/* RPMB Request Types */
+#define VIRTIO_RPMB_REQ_PROGRAM_KEY        0x0001
+#define VIRTIO_RPMB_REQ_GET_WRITE_COUNTER  0x0002
+#define VIRTIO_RPMB_REQ_DATA_WRITE         0x0003
+#define VIRTIO_RPMB_REQ_DATA_READ          0x0004
+#define VIRTIO_RPMB_REQ_RESULT_READ        0x0005
+
+/* RPMB Response Types */
+#define VIRTIO_RPMB_RESP_PROGRAM_KEY       0x0100
+#define VIRTIO_RPMB_RESP_GET_COUNTER       0x0200
+#define VIRTIO_RPMB_RESP_DATA_WRITE        0x0300
+#define VIRTIO_RPMB_RESP_DATA_READ         0x0400
+\end{lstlisting}
+
+\begin{description}
+\item[\field{VIRTIO_RPMB_REQ_PROGRAM_KEY}] requests for authentication key programming.
+  If VIRTIO_RPMB_REQ_RESULT_READ is requested, the device returns the RPMB frame with
+  the response (VIRTIO_RPMB_RESP_PROGRAM_KEY), the calculated MAC and the result.
+
+\item[\field{VIRTIO_RPMB_REQ_GET_WRITE_COUNTER}] requests for reading the write counter.
+   The device returns the RPMB frame with the response (VIRTIO_RPMB_RESP_GET_COUNTER),
+   the writer counter, a copy of the nonce received in the request, the calculated
+   MAC and the result.
+
+\item[\field{VIRTIO_RPMB_REQ_DATA_WRITE}] requests for authenticated data write.
+   If VIRTIO_RPMB_REQ_RESULT_READ is requested, the device returns the RPMB data
+   frame with the response (VIRTIO_RPMB_RESP_DATA_WRITE), the incremented counter value,
+   the data address, the calculated MAC and the result.
+
+\item[\field{VIRTIO_RPMB_REQ_DATA_READ}] requests for authenticated data read.
+   The device returns the RPMB frame with the response (VIRTIO_RPMB_RESP_DATA_READ),
+   the block count, a copy of the nonce received in the request, the address,
+   the data, the calculated MAC and the result.
+
+\item[\field{VIRTIO_RPMB_REQ_RESULT_READ}] requests for a returned result.
+   It is used following with VIRTIO_RPMB_REQ_PROGRAM_KEY or VIRTIO_RPMB_REQ_DATA_WRITE
+   request types for a returned result in one or multiple RPMB frames. If it's not
+   requested, the device will not return result frame to the driver.
+\end{description}
+
+
+\subsubsection{Device Operation: Request Queue}\label{sec:Device Types / RPMB Device / Device Operation / Device Operation: Request Queue}
+
+The request information is delivered in RPMB frame.
+The frame is in size of 512B.
+
+\begin{lstlisting}
+struct virtio_rpmb_frame {
+        u8 stuff[196];
+        u8 key_mac[32];
+        u8 data[256];
+        u8 nonce[16];
+        be32 write_counter;
+        be16 address;
+        be16 block_count;
+        be16 result;
+        be16 req_resp;
+};
+
+/* RPMB Operation Results */
+#define VIRTIO_RPMB_RES_OK                     0x0000
+#define VIRTIO_RPMB_RES_GENERAL_FAILURE        0x0001
+#define VIRTIO_RPMB_RES_AUTH_FAILURE           0x0002
+#define VIRTIO_RPMB_RES_COUNT_FAILURE          0x0003
+#define VIRTIO_RPMB_RES_ADDR_FAILURE           0x0004
+#define VIRTIO_RPMB_RES_WRITE_FAILURE          0x0005
+#define VIRTIO_RPMB_RES_READ_FAILURE           0x0006
+#define VIRTIO_RPMB_RES_NO_AUTH_KEY            0x0007
+#define VIRTIO_RPMB_RES_WRITE_COUNTER_EXPIRED  0x0080
+\end{lstlisting}
+
+\begin{description}
+\item[\field{stuff}] Padding for the frame.
+
+\item[\field{key_mac}] is the authentication key or the message
+   authentication code (MAC) depending on the request/response type.
+   If the request is VIRTIO_RPMB_REQ_PROGRAM_KEY, it's used as an
+   authentication key. Otherwise, it's used as MAC. The MAC is calculated
+   using HMAC SHA-256. It takes as input a key and a message. The key
+   used for the MAC calculation is always the 256-bit RPMB authentication
+   key. The message used as input to the MAC calculation is the
+   concatenation of the fields in the RPMB frames excluding stuff bytes
+   and the MAC itself.
+
+\item[\field{data}] is used to be written or read via authenticated
+   read/write access. It's fixed 256B.
+
+\item[\field{nonce}] is a random number generated by the user for the read
+   or get write counter requests and copied to the response by the device.
+   It's used for anti-replay protection.
+
+\item[\field{writer_counter}] is the counter value for the total amount of
+   the successful authenticated data write requests.
+
+\item[\field{address}] is the address of the data to be written to or read
+   from the RPMB virtio device. It is the number of the accessed
+   half sector (256B).
+
+\item[\field{block_count}] is the number of blocks (256B) requested to be
+   read/written. It's limited by \field{max_wr_cnt} or \field{max_rd_cnt}.
+   For RPMB read request, one virtio buffer including request command and
+   the subsequent [\field{block_count}] virtio buffers for response data
+   are placed in the queue.
+   For RPMB write request, [\field{block_count}] virtio buffers including
+   request command and data are placed in the queue.
+
+\item[\field{result}] includes information about the status of access made
+   to the device. It is written by the device.
+
+\item[\field{req_resp}] is the type of request or response, to/from the device.
+\end{description}
+
+\devicenormative{\paragraph}{Device Operation: Program Key}{Device Types / RPMB Device / Device Operation / Device Operation: Program Key}
+
+If VIRTIO_RPMB_REQ_RESULT_READ is requested, the device SHOULD return the
+RPMB frame with the response, the calculated MAC and the result:
+
+\begin{enumerate}
+\item If the \field{block_count} is not set to 1 then
+   VIRTIO_RPMB_RES_GENERAL_FAILURE SHOULD be responded as \field{result}.
+
+\item If the programming of authentication key fails,
+   then VIRTIO_RPMB_RES_WRITE_FAILURE SHOULD be responded as \field{result}.
+
+\item If some other error occurs then returned result
+   VIRTIO_RPMB_RES_GENERAL_FAILURE SHOULD be responded as \field{result}.
+
+\item The \field{req_resp} value VIRTIO_RPMB_RESP_PROGRAM_KEY SHOULD be responded.
+\end{enumerate}
+
+\devicenormative{\paragraph}{Device Operation: Get Write Counter}{Device Types / RPMB Device / Device Operation / Device Operation: Get Write Counter}
+
+If the authentication key is not yet programmed then VIRTIO_RPMB_RES_NO_AUTH_KEY
+SHOULD be returned in \field{result}.
+
+If block count has not been set to 1 then VIRTIO_RPMB_RES_GENERAL_FAILURE
+SHOULD be responded as \field{result}.
+
+The \field{req_resp} value VIRTIO_RPMB_RESP_GET_COUNTER SHOULD be responded.
+
+\devicenormative{\paragraph}{Device Operation: Data Write}{Device Types / RPMB Device / Device Operation / Device Operation: Data Write}
+
+If VIRTIO_RPMB_REQ_RESULT_READ is requested, the device SHOULD return the RPMB data
+frame with the response VIRTIO_RPMB_RESP_DATA_WRITE, the incremented counter value,
+the data address, the calculated MAC and the result:
+
+\begin{enumerate}
+\item If the authentication key is not yet programmed,
+   then VIRTIO_RPMB_RES_NO_AUTH_KEY SHOULD be returned in \field{result}.
+
+\item If block count is zero or greater than \field{max_wr_cnt} then
+   VIRTIO_RPMB_RES_GENERAL_FAILURE SHOULD be responded.
+
+\item The device MUST check whether the write counter has expired.
+  If the write counter is expired then the \field{result} SHOULD be set to
+  VIRTIO_RPMB_RES_WRITE_COUNTER_EXPIRED.
+
+\item If there is an error in the address (out of range) then the \field{result}
+  SHOULD be set to VIRTIO_RPMB_RES_ADDR_FAILURE.
+
+\item The device MUST calculate the MAC taking authentication key and frame as input,
+  and compare this with the MAC in the request. If the two MAC’s are different
+  then VIRTIO_RPMB_RES_AUTH_FAILURE SHOULD be returned in \field{result}.
+
+\item If the writer counter in the request is different from the one maintained
+   by the device then VIRTIO_RPMB_RES_COUNT_FAILURE SHOULD  be returned in \field{result}.
+
+\item If the MAC and write counter comparisons are matched then the write request
+   is considered to be authenticated. The data from the request SHOULD be written to the
+   address indicated in the request and the write counter SHOULD be incremented by 1.
+
+\item If the write fails then the \field{result} SHOULD be VIRTIO_RPMB_RES_WRITE_FAILURE.
+
+\item If some other error occurs during the writing procedure then the \field{result}
+   SHOULD be VIRTIO_RPMB_RES_GENERAL_FAILURE.
+
+\item The \field{req_resp} value VIRTIO_RPMB_RESP_DATA_WRITE SHOULD be responded.
+\end{enumerate}
+
+\devicenormative{\paragraph}{Device Operation: Data Read}{Device Types / RPMB Device / Device Operation / Device Operation: Data Read}
+
+If the authentication key is not yet programmed then VIRTIO_RPMB_RES_NO_AUTH_KEY
+SHOULD be returned in \field{result}.
+
+If block count has not been set to 1 then VIRTIO_RPMB_RES_GENERAL_FAILURE SHOULD be
+responded as \field{result}.
+
+If there is an error in the address (out of range) then the \field{result} SHOULD
+be set to VIRTIO_RPMB_RES_ADDR_FAILURE.
+
+If data fetch from addressed location inside the device fails then the \field{result}
+SHOULD be VIRTIO_RPMB_RES_READ_FAILURE.
+
+If some other error occurs during the read procedure then the \field{result}
+SHOULD be VIRTIO_RPMB_RES_GENERAL_FAILURE.
+
+The \field{req_resp} value VIRTIO_RPMB_RESP_DATA_READ SHOULD be responded.
+
+\devicenormative{\paragraph}{Device Operation: Result Read}{Device Types / RPMB Device / Device Operation / Device Operation: Result Read}
+
+If the \field{block_count} has not been set to 1 of VIRTIO_RPMB_REQ_RESULT_READ
+request then VIRTIO_RPMB_RES_GENERAL_FAILURE SHOULD be responded as \field{result}.
+
+\drivernormative{\subsubsection}{Device Operation}{Device Types / RPMB Device / Device Operation}
+
+The RPMB frames MUST not be packed by the driver.
+The driver MUST configure, initialize and format virtqueue for the RPMB requests received from its caller then send it to the device.
+
+\devicenormative{\subsubsection}{Device Operation}{Device Types / RPMB Device / Device Operation}
+
+The virtio-rpmb device could be backed in a number of ways. It SHOULD
+   keep consistent behaviors with hardware as described in paragraph
+   6.6.22 of \hyperref[intro:eMMC]{eMMC}.
+   Some elements are maintained by the device:
+\begin{enumerate}
+\item The device MUST maintain a one-time programmable authentication key.
+   It cannot be overwritten, erased or read. The key is used to
+   authenticate the accesses when MAC is calculated. This key MUST be
+   kept regardless of device reset or reboot.
+\item The device MUST maintain a read-only monotonic write counter. It
+  MUST be initialized to zero and added by one automatically along with
+   successful write operation. The value cannot be reset. After
+   the counter has reached its maximum value 0xFFFF FFFF, it will
+   not be incremented anymore. This counter MUST be kept regardless
+   of device reset or reboot.
+\item The device MUST maintain the data for read/write via authenticated
+   access.
+\end{enumerate}