[PATCH v1] virtio-blk: Add inline encryption support

From: linlzhan <[email protected]>

Inline encryption on virtio block can only be supported when
the new feature bit VIRTIO_BLK_F_ICE is negotiated.

Extend struct virtio_blk_config and struct virtio_blk_req,
so that crypto capabilities can be got in the frontend and
encryption metadata can be sent to the backend, together with
each I/O transaction.

Signed-off-by: linlzhan <[email protected]>
---
 device-types/blk/description.tex | 69 ++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)

diff --git a/device-types/blk/description.tex b/device-types/blk/description.tex
index 2712ada..23d8dc0 100644
--- a/device-types/blk/description.tex
+++ b/device-types/blk/description.tex
@@ -66,6 +66,11 @@ \subsection{Feature bits}\label{sec:Device Types / Block Device / Feature bits}
 	(ZNS). For brevity, these standard documents are referred as "ZBD standards"
 	from this point on in the text.
 
+\item[VIRTIO_BLK_F_ICE(22)] Inline Crypto Extensions are supported. When this
+     is negotiated, the device exposes crypto characteristics in configuration
+     space and the driver SHALL provide an extended request header containing a
+     crypto payload for block I/O.
+
 \end{description}
 
 \subsubsection{Legacy Interface: Feature bits}\label{sec:Device Types / Block Device / Feature bits / Legacy Interface: Feature bits}
@@ -128,6 +133,11 @@ \subsection{Device configuration layout}\label{sec:Device Types / Block Device /
                 u8 model;
                 u8 unused2[3];
         } zoned;
+        struct virtio_blk_crypto_characteristics {
+                __virtio16 slot_info;
+                __virtio16 reserved;
+                __virtio32 capability;
+        } crypto;
 };
 \end{lstlisting}
 
@@ -215,6 +225,25 @@ \subsection{Device configuration layout}\label{sec:Device Types / Block Device /
 terminated by the device with a "zone resources exceeded" error as defined for
 specific commands later.
 
+If the VIRTIO_BLK_F_ICE feature is negotiated, then in
+\field{virtio_blk_crypto_characteristics},
+\begin{itemize}
+\item \field{slot_info} value packs two 8-bits values:
+    \begin{itemize}
+        \item Bits~\[15:8] (\emph{max\_slots}): the maximum number of supported
+            crypto key slots.
+        \item Bits~\[7:0] (\emph{slot\_offset}): an offset applied to slot numbering.
+    \end{itemize}
+\item \field{capability} value packs four 8-bits values:
+    \begin{itemize}
+        \item Bits~\[31:24]: crypto algorithm id.
+        \item Bits~\[23:16]: mask of data unit size.
+        \item Bits~\[15:8]: crypto key size.
+        \item Bits~\[7:0]: unused.
+    \end{itemize}
+\end{itemize}
+
+
 \subsubsection{Legacy Interface: Device configuration layout}\label{sec:Device Types / Block Device / Device configuration layout / Legacy Interface: Device configuration layout}
 When using the legacy interface, transitional devices and drivers
 MUST format the fields in struct virtio_blk_config
@@ -278,6 +307,10 @@ \subsection{Device Initialization}\label{sec:Device Types / Block Device / Devic
     \field{zoned} can be read by the driver to determine the zone
     characteristics of the device. All \field{zoned} fields are read-only.
 
+\item If the VIRTIO_BLK_F_ICE feature is negotiated, the fields in
+    \field{crypto} can be read by the driver to determine the inline crypto
+    characteristics of the device. All \field{crypto} fields are read-only.
+
 \end{enumerate}
 
 \drivernormative{\subsubsection}{Device Initialization}{Device Types / Block Device / Device Initialization}
@@ -317,6 +350,9 @@ \subsection{Device Initialization}\label{sec:Device Types / Block Device / Devic
     driver SHOULD ignore all other fields in \field{zoned}.
 \end{itemize}
 
+If the VIRTIO_BLK_F_ICE feature is negotiated, then the driver must validate
+    the max_slots in \field{slot_info} before the slot usage.
+
 \devicenormative{\subsubsection}{Device Initialization}{Device Types / Block Device / Device Initialization}
 
 Devices SHOULD always offer VIRTIO_BLK_F_FLUSH, and MUST offer it
@@ -402,6 +438,16 @@ \subsection{Device Initialization}\label{sec:Device Types / Block Device / Devic
 \item the device MUST initialize padding bytes \field{unused2} to 0.
 \end{itemize}
 
+If the VIRTIO_BLK_F_ICE feature is negotiated, then the fields in \field{cryto}
+struct in the configuration space MUST be set by the device.
+\begin{itemize}
+\item the \field{slot_info} field of \field{crypto} MUST be set by the device to a
+    max_slots in the higher 8 bits and slot_offset in the lower 8 bits.
+
+\item the \field{capability} field of \field{crypto} MUST be set by the device
+    to a crypto capability read from the storage register.
+\end{itemize}
+
 \subsubsection{Legacy Interface: Device Initialization}\label{sec:Device Types / Block Device / Device Initialization / Legacy Interface: Device Initialization}
 
 Because legacy devices do not have FEATURES_OK, transitional devices
@@ -436,6 +482,13 @@ \subsection{Device Operation}\label{sec:Device Types / Block Device / Device Ope
         le32 type;
         le32 reserved;
         le64 sector;
+        struct virtio_blk_crypto_payload {
+            u8 slot;
+            u8 activate;
+            le16 reserved1;
+            le32 reserved2;
+            le64 data_unit_num;
+        } payload;
         u8 data[];
         u8 status;
 };
@@ -463,6 +516,20 @@ \subsection{Device Operation}\label{sec:Device Types / Block Device / Device Ope
 the read or write is to occur. This field is unused and set to 0 for
 commands other than read, write and some zone operations.
 
+The \field{payload} consists of the encryption information for current
+request. It need to be set by the driver only when the feature VIRTIO_BLK_F_ICE
+is negotiated.
+\begin{itemize}
+\item The \field{slot} filed in \field{payload} indicates the ICE
+  (Inline Crypto Encryption) slot index where the key resides in.
+
+\item The \field{activate} filed in \field{payload} implies this is a
+  encryption request.
+
+\item The \field{data_unit_num} filed in \field{payload} indicates the
+  starting block of the request.
+\end{itemize}
+
 VIRTIO_BLK_T_IN requests populate \field{data} with the contents of sectors
 read from the block device (in multiples of 512 bytes).  VIRTIO_BLK_T_OUT
 requests write the contents of \field{data} to the block device (in multiples
@@ -912,6 +979,8 @@ \subsection{Device Operation}\label{sec:Device Types / Block Device / Device Ope
 successfully, failed, or were processed by the device at all if the request
 failed with VIRTIO_BLK_S_IOERR.
 
+A driver MUST set \field{activate} to 0 for a non VIRTIO_BLK_F_ICE request.
+
 The following requirements only apply if the VIRTIO_BLK_F_ZONED feature is
 negotiated.
 
-- 
2.34.1