virtio — archive

[Michael S. Tsirkin <mst@redhat.com>]

From: Max Gurtovoy <mgurtovoy@nvidia.com> These commands are used for essential administrative and management operations. Following patches will introduce an interface for submitting these commands to the device. Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> --- admin.tex | 99 ++++++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 94 insertions(+), 5 deletions(-) diff --git a/admin.tex b/admin.tex index 6e9434a..4840dd4 100644 --- a/admin.tex +++ b/admin.tex @@ -9,8 +9,10 @@ \section{Device groups}\label{sec:Basic Facilities of a Virtio Device / Device g \item[Parent device] or parent, the device controlling the group. \item[Member device] - a device within a group. Parent device itself may, or may - not be a member of the group. + a device within a group. Parent device itself is not + a member of the group. In the future it is envisoned that + new group types may be introduced where the parent + device is a member of the group. \item[Member identifier] each member has this indentifier, unique within the group and used to address it through the parent device. @@ -20,9 +22,10 @@ \section{Device groups}\label{sec:Basic Facilities of a Virtio Device / Device g and what kind of control does the parent have. \item[Group identifier] each group has this identifier, unique within the parent device. - this specifies the group type and possibly selects the - group if multiple groups of the same type can be controlled by the same - parent device. + This specifies the group type. In the future it is + envisoned that new group types will be introduced where the group + identifier also selects the group if multiple groups of the same + type can be controlled by the same parent device. \end{description} A single group type is currently specified: @@ -46,4 +49,90 @@ \section{Device groups}\label{sec:Basic Facilities of a Virtio Device / Device g PCI transport (see \ref{sec:Virtio Transport Options / Virtio Over PCI Bus}). \end{description} +\subsection{Group administration commands}\label{sec:Basic Facilities of a Virtio Device / Group administration commands} + +Group administration commands can be issued through a parent +device to control member devices of a group. This mechanism can +be used, for example, to configure a member device before it is +initialized by its driver. + +All the group administration commands are of the following form: + +\begin{lstlisting} +struct virtio_admin_cmd { + /* Device-readable part */ + le16 opcode; + /* + * 1 - SR-IOV + * 2 - 65535 reserved + */ + le16 group_id; + /* unused, reserved for future extensions */ + u8 reserved1[12]; + le64 group_member_id; + u8 command_specific_data[]; + + /* Device-writable part */ + u8 status; + u8 command_specific_error; + /* unused, reserved for future extensions */ + u8 reserved2[6]; + u8 command_specific_result[]; +}; +\end{lstlisting} + +For all commands, \field{opcode}, \field{group_id} and if +necessary \field{group_member_id} and \field{command_specific_data} are +set by the driver, and the parent device sets \field{status} and if +needed \field{command_specific_error} and +\field{command_specific_result}. + +As a rule, any unused device-readable fields are set to zero by the driver +and ignored by the device. Any unused device-writeable fields are set to zero +by the device and ignored by the driver. + +\field{opcode} specifies the command. The valid +values for \field{opcode} can be found in the following table: + +\begin{tabular}{|l|l|} +\hline +opcode & Command Description \\ +\hline \hline +0000h - 7FFFh & Group administration commands \\ +\hline +8000h - FFFFh & Reserved \\ +\hline +\end{tabular} + +The \field{group_id} specifies the device group. +The \field{group_member_id} specifies the member device within the group. +See section \ref{sec:Introduction / Terminology / Device group} +for the definition of the group identifier and group member +identifier. + +The following table describes possible \field{status} values: + +\begin{tabular}{|l|l|l|} +\hline +Status & Name & Description \\ +\hline \hline +00h & VIRTIO_ADMIN_STATUS_OK & successful completion \\ +\hline +01h & VIRTIO_ADMIN_STATUS_CS_ERR & command specific error \\ +\hline +02h & VIRTIO_ADMIN_STATUS_OPCODE_UNSUPPORTED & unsupported or invalid \field{opcode} \\ +\hline +03h & VIRTIO_ADMIN_STATUS_INVALID_FIELD & invalid field within command specific data \\ +\hline +04h & VIRTIO_ADMIN_STATUS_INVALID_GROUP & invalid group identifier was set \\ +\hline +05h & VIRTIO_ADMIN_STATUS_INVALID_MEM & invalid group member identifier was set \\ +\hline +\end{tabular} + +The \field{command_specific_error} should be inspected by the driver only if \field{status} is set to +VIRTIO_ADMIN_STATUS_CS_ERR by the device. In this case, the +contents of \field{command_specific_error} +holds the command specific error. If \field{status} is not set to VIRTIO_ADMIN_STATUS_CS_ERR, the +\field{command_specific_error} value is undefined and should be ignored by the driver. -- MST