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Subject: [PATCH V3 RESEND 2/4] Introduce the commands set of the transport vq
This commit introduces the commands set of the transport virtqueue, including: The command to query available resources of the management device The commands to create / destroy the managed devices. The commands to config the managed devices. The commands to config virtqueues of the managed devices. Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com> --- content.tex | 636 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 636 insertions(+) diff --git a/content.tex b/content.tex index c747d21..190f3a0 100644 --- a/content.tex +++ b/content.tex @@ -2975,6 +2975,642 @@ \subsection{Format of Commands through Transport Virtqueue}\label{sec:Virtio Tra The \field{device_id} value 0 is used to identify the management device itself. \field{class} is an identifier of a set of commands with similar purposes. + +\subsection{Available Resource of the Management Device}\label{sec:Virtio Transport Options / Virtio Over Transport Virtqueue / Available Resource of the Management Device} + +When VIRTIO_F_TRANSPT_VQ is negotiated with the management device, +statistical information of available resources on the management device could be fetched +by the following command: + +\begin{lstlisting} +#define VIRTIO_TRANSPTQ_CTRL_AVAIL_RES 1 (class) + #define VIRTIO_TRANSPTQ_CTRL_AVAIL_RES_GET 0 (command) +\end{lstlisting} + +VIRTIO_TRANSPTQ_CTRL_AVAIL_RES_GET command is used to get the statistical information of the available +resource of a management device. There is no command-out-data for VIRTIO_TRANSPTQ_CTRL_AVAIL_RES_GET +command. The management device fills command-in-data in the following format: + +\begin{lstlisting} +struct virtio_mgmt_dev_avail_res { + /* The number of management device total remaining available free + * virtqueues for the managed devices + */ + u16 num_avail_vqs; + /* The minimal number of virtqueues for a managed device */ + u16 min_dev_vqs; + /* The maximum number of virtqueues for a managed device */ + u16 max_dev_vqs; + /* The number of managed devices that can be created with min_vqs virtqueues */ + u16 num_avail_dev; +}; +\end{lstlisting} + +\field{max_avail_dev} MAY not equal to \field{num_avail_vqs} divided by \field{min_vqs} +due to the limitations of of other resources. + +\devicenormative{\subsubsection}{Available Resource of the Management Device}{Virtio Transport Options / +Virtio Over Transport Virtqueue / Available Resource of the Management Device} + +The management device MUST fail VIRTIO_TRANSPTQ_CTRL_AVAIL_RES_GET command if \field{device_id} is not 0 + +\drivernormative{\subsubsection}{Available Resource of the Management Device}{Virtio Transport Options / +Virtio Over Transport Virtqueue / Available Resource of the Management Device} + +The management device driver MUST use 0 as \field{device_id} for +VIRTIO_TRANSPTQ_CTRL_AVAIL_RES_GET command. + +\subsection{Create and Destroy Managed Devices}\label{sec:Virtio Transport Options / Virtio Over Transport Virtqueue / Create and Destroy Managed Devices} + +When VIRTIO_F_TRANSPT_VQ is negotiated with the management device, +managed devices must be created and destroyed through the transport virtqueue. + +\begin{lstlisting} +#define VIRTIO_TRANSPORTQ_CTRL_DEV 2 + #define VIRTIO_TRANSPORTQ_CTRL_DEV_CREATE 0 + #define VIRTIO_TRANSPORTQ_CTRL_DEV_DESTROY 1 + +struct virtio_transportq_ctrl_dev_attribute { + u64 device_features[2]; + u32 virtio_device_id; + u8 dev_config[]; +}; +\end{lstlisting} + +The VIRTIO_TRANSPORTQ_CTRL_DEV_CREATE command is used to create a managed device. + +As described in struct virtio_transportq_ctrl_dev_attribute, the command-out-data for VIRTIO_TRANSPTQ_CTRL_DEV_CREATE includes: +\begin{itemize*} +\item \field{device_features}: the 128-bit device feature bits (defined in section \ref{sec:Basic Facilities of a Virtio Device / Feature Bits}) +of the managed device. +\item \field{virtio_device_id}: the virtio device id defined in Chapter \ref{sec:Device Types}. +\item \field{dev_config}: the device type specific configurations. E.g., for a virtio-net device, +it is struct virtio_net_config in section \ref{sec:Device Types / Network Device / Device configuration layout}; +for a virtio-block device, it is struct virtio_blk_config in section \ref{sec:Device Types / Block Device / Device configuration layout} +\end{itemize*} + +When succeed, the device returns a 64 bits UUID as an unique identifier of the created managed device in command-in-data. + +The VIRTIO_TRANSPORTQ_CTRL_DEV_DESTROY command is used to destroy a +managed device which is identified by its 64 bits UUID +\field{device_id}. There's no command-in-data nor command-out-data for +VIRTIO_TRANSPTQ_CTRL_DEV_DESTROY command. + +\devicenormative{\subsubsection}{Create and Destroy Managed Devices}{Virtio Transport Options / Virtio Over Transport Virtqueue / Create and Destroy Managed Devices} + +The management device MUST fail VIRTIO_TRANSPORTQ_CTRL_DEV_CREATE command +if \field{device_id} is not 0. + +The management device MUST fail VIRTIO_TRANSPORTQ_CTRL_DEV CREATE command +if \field{device_features} exceeds the features that can be provided from the management device. + +The management device MUST fail VIRTO_TRANSPORTQ_CTRL_DEV_DESTROY command +if \field{device_id} is 0. + +\drivernormative{\subsubsection}{Create and Destroy Managed Devices}{Virtio Transport Options / Virtio Over Transport Virtqueue / Create and Destroy Managed Devices} + +The management device driver MUST use 0 as \field{device_id} for +TRANSPORTQ_CTRL_DEV_CREATE command. + +\subsection{Features Negotiation}\label{sec:Virtio Transport Options / Virtio +Over Transport Virtqueue / Features Negotiation} + +When VIRTIO_F_TRANSPT_VQ is negotiated with the management device, +the features negotiation of managed devices is done by the +following commands: + +\begin{lstlisting} +#define VIRTIO_TRANSPTQ_CTRL_FEAT 3 + #define VIRTIO_TRANSPTQ_CTRL_FEAT_DEVICE_GET 0 + #define VIRTIO_TRANSPTQ_CTRL_FEAT_DRIVER_SET 1 + #define VIRTIO_TRANSPTQ_CTRL_FEAT_DRIVER_GET 2 +\end{lstlisting} + +The VIRTIO_TRANSPTQ_CTRL_FEAT_DEVICE_GET command is used to get the features offered +by a managed device. The command-in-data is the 128-bit feature bits +(defined in section \ref{sec:Basic Facilities of a Virtio Device / Feature Bits}). +There is no command-out-data. + +The VIRTIO_TRANSPTQ_CTRL_FEAT_DRIVER_SET command is for the driver to accept feature +bits offered by the managed device. The command-out-data is the 128-bit feature bits +passed to the managed device. There is no command-in-data. + +The VIRTIO_TRANSPTQ_CTRL_FEAT_DRIVER_GET command is used to get the features accepted +by both the managed device driver and the managed device. The command-in-data is the +128-bit feature bits. There is no command-out-data. + +\devicenormative{\subsubsection}{Features Negotiation}{Virtio Transport Options / +Virtio Over Transport Virtqueue / Features Negotiation} + +The management device MUST fail VIRTIO_TRANSPTQ_F_CTRL_FEAT class commands if +\field{device_id} is 0. + +\subsection{Device Status}\label{sec:Virtio Transport Options / Virtio Over +Transport Virtqueue / Device Status} + +When VIRTIO_F_TRANSPT_VQ is negotiated with the management device, +the device status of a managed device can be accessed by the following +commands: + +\begin{lstlisting} +#define VIRTIO_TRANSPTQ_CTRL_STATUS 4 + #define VIRTIO_TRANSPTQ_CTRL_STATUS_GET 0 + #define VIRTIO_TRANSPTQ_CTRL_STATUS_SET 1 +\end{lstlisting} + +The VIRTIO_TRANSPTQ_CTRL_STATUS_GET command is used to get the device status of +a managed device. The command-in-data is the 8-bit status +returned from the device. There's no command-out-data for this +command. + +The VIRTIO_TRANSPTQ_CTRL_STATUS_SET command is used to set the device status of +a managed device. The command-out-data is the 8-bit status +to set to the device. There's no command-in-data for this command. + +\devicenormative{\subsubsection}{Device Status}{Virtio Transport Options / Virtio +Over Transport Virtqueue / Device Status} + +The management device MUST reset the managed device when 0 +is set via VIRTIO_TRANSPTQ_CTRL_STATUS_SET, the success of this +command demonstrates the success of the reset. + +The management device MUST present 0 through +VIRTIO_TRANSPTQ_CTRL_STATUS_GET once the reset is successfully done. + +The management device MUST fail the device status access if +\field{device_id} is 0. + +\drivernormative{\subsubsection}{Device Status}{Virtio Transport Options / Virtio +Over Transport Virtqueue / Device Status} + +After writing 0 via VIRTIO_TRANSPTQ_CTRL_STATUS_SET, the driver MUST wait +for the success of the command before re-initializing the device. + +\subsection{Device Generation}\label{sec:Virtio Transport Options / Virtio Over Transport Virtqueue / Device Generation} + +When VIRTIO_F_TRANSPT_VQ is negotiated with the management device, +the device generation count can be read from the following commands: + +\begin{lstlisting} +#define VIRTIO_TRANSPTQ_CTRL_GENERATION 5 + #define VIRTIO_TRANSPTQ_CTRL_GENERATION_GET 0 +\end{lstlisting} + +The VIRTIO_TRANSPTQ_CTRL_GENERATION_GET command is used to get the device configuration generation count +of the managed device. The command-in-data is the one byte device +generation returned from the device. There's no command-out-data for +this command. + +\devicenormative{\subsubsection}{Device Generation}{Virtio Transport Options / Virtio Over Transport Virtqueue / Device Generation} + +The managed device MUST present a changed generation count after the driver +has read any device-specific configuration values if the values have been changed +during the last read. + +The management device MUST fail the device generation access if \field{device_id} is 0. + +\subsection{Device Specific Configuration}\label{sec:Virtio Transport Options / +Virtio Over Transport Virtqueue / Device Specific Configuration} + +When VIRTIO_F_TRANSPT_VQ is negotiated with the management device, +the device config space contents of a managed device can be accessed through +the following commands: + +\begin{lstlisting} +#define VIRTIO_TRANSPTQ_CTRL_CONFIG 6 + #define VIRTIO_TRANSPTQ_CTRL_CONFIG_GET 0 + #define VIRTIO_TRANSPTQ_CTRL_CONFIG_SET 1 + +struct virtio_transportq_ctrl_dev_config_get { + u32 offset; + u32 size; +}; + +struct virtio_transportq_ctrl_dev_config_set { + u32 offset; + u32 size; + u8 data[]; +}; +\end{lstlisting} + +The VIRTIO_TRANSPTQ_CTRL_CONFIG_GET command is used to read data from the +device configuration space. The command-out-data is the \field{offset} +from the start of the config space and the \field{size} +of the data (as described in struct virtio_transportq_ctrl_dev_config_get). +The command-in-data is an array of the data that read from the config space. + +The VIRTIO_TRANSPTQ_CTRL_CONFIG_SET command is used to write data to the device +configuration space. The command-out-data contains the +\field{offset} from the start of the config space, the \field{size} of the data and +the \field{data} to be written (as described in struct virtio_transportq_ctrl_dev_config_set). +There's no command-in-data for this command. + +\devicenormative{\subsubsection}{Device Specific Configuration}{Virtio Transport +Options / Virtio Over Transport Virtqueue / Device Specific Configuration} + +The management device MUST fail the device configuration space access +if the driver access the range which is outside the config space. + +The management device MUST fail the device configuration space access +if \field{device_id} is 0. + +\subsection{MSI Configuration}\label{sec:Virtio Transport Options / Virtio Over +Transport Virtqueue / MSI Configuration} + +When VIRTIO_F_TRANSPT_VQ is negotiated with the management device, +the MSI entries of a managed device can be accessed through the following command: + +\begin{lstlisting} +#define VIRTIO_TRANSPTQ_CTRL_MSI 7 + #define VIRTIO_TRANSPTQ_CTRL_MSI_VQ_GET 0 + #define VIRTIO_TRANSPTQ_CTRL_MSI_VQ_SET 1 + #define VIRTIO_TRANSPTQ_CTRL_MSI_VQ_ENABLE 2 + #define VIRTIO_TRANSPTQ_CTRL_MSI_CONFIG_GET 3 + #define VIRTIO_TRANSPTQ_CTRL_MSI_CONFIG_WET 4 + #define VIRTIO_TRANSPTQ_CTRL_MSI_CONFIG_ENABLE 5 + +struct virtio_transportq_ctrl_msi_vq_config { + u16 queue_index; + u64 address; + u32 data; + u8 padding[2]; +}; + +struct virtio_transportq_ctrl_msi_vq_enable { + u16 queue_index; + u8 enable; + u8 padding[5]; +}; + +struct virtio_transportq_ctrl_msi_config { + u64 address; + u32 data; + u8 padding[4]; +}; +\end{lstlisting} + +The VIRTIO_TRANSPTQ_CTRL_MSI_VQ_GET command is used to read the MSI entry of a +specific virtqueue. The command-out-data is the queue index. The command-in-data contains +\field{queue_index}, the \field{address} and \field{data} +(as described in struct virtio_transportq_ctrl_msi_vq_config). + + +The VIRTIO_TRANSPTQ_CTRL_MSI_VQ_SET command is used to set the MSI entry for a +specific virtqueue. The command-out-data is the \field{queue_index}, +\field{address} and \field{data} (as described in struct virtio_transportq_ctrl_msi_vq_config). +There is no command-in-data. + +The VIRTIO_TRANSPTQ_CTRL_MSI_VQ_ENABLE command is used to enable or disable +the MSI interrupt for a specific virtqueue. The command-out-data is the +\field{queue_index} and a byte \field{enable} which representing ENABLE or DISABLE the MSI. +(as described in struct virtio_transportq_ctrl_msi_vq_enable). + +\begin{lstlisting} +#define VIRTIO_TRANSPTQ_CTRL_MSI_VQ_ENABLE 1 +#define VIRTIO_TRANSPTQ_CTRL_MSI_VQ_DISABLE 0 +\end{lstlisting} + +The VIRTIO_TRANSPTQ_CTRL_MSI_CONFIG_GET command is used to read the MSI entry +of the config interrupt. The command-in-data contains the \field{address} and +\field{data} (as described in struct virtio_transportq_ctrl_msi_config). +There is no command-out-data. + +The VIRTIO_TRANSPTQ_CTRL_MSI_CONFIG_SET command is used to set the MSI entry +for the config interrupt. The command-out-data is the \field{address} and +\field{data} (as described in struct virtio_transportq_ctrl_msi_config). +There is no command-in-data. + +The VIRTIO_TRANSPTQ_CTRL_MSI_CONFIG_ENABLE command is used to enable or disable +the MSI interrupt for config space. The command-out-data is a byte which representing +ENABLE or DISABLE the config MSI. +There is no command-in-data + +\begin{lstlisting} +#define VIRTIO_TRANSPTQ_CTRL_MSI_CFG_ENABLE 1 +#define VIRTIO_TRANSPTQ_CTRL_MSI_CFG_DISABLE 0 +\end{lstlisting} + +\devicenormative{\subsubsection}{MSI Configuration}{Virtio Transport Options / Virtio +ver Transport Virtqueue / MSI Configuration} + +The managed device MUST disable the MSI interrupts for both virtqueues and config space +upon a reset. + +Once a MSI entry is disabled, the managed device MUST not send any interrupts +by this MSI entry. + +\drivernormative{\subsubsection}{MSI Configuration}{Virtio Transport Options / Virtio +Over Transport Virtqueue / MSI Configuration} + +The driver MUST allocate transport or platform specific MSI entries +for both virtqueues and config space if it wants to use interrupts. + +The driver MAY choose to disable the MSI if polling mode is used. + +\subsection{Virtqueue Address}\label{sec:Virtio Transport Options / Virtio Over +Transport Virtqueue / Virtqueue Address} + +When VIRTIO_F_TRANSPT_VQ is negotiated with the management device, +the addresses of a specific virtqueue are accessed through the following command: + +\begin{lstlisting} +#define VIRTIO_TRANSPTQ_CTRL_VQ_ADDR 8 + #define VIRTIO_TRANSPTQ_CTRL_VQ_ADDR_SET 1 + +struct virtio_transportq_ctrl_vq_addr { + u16 queue_index; + u64 descriptor_area; + u64 device_area; + u64 driver_area; + u8 padding[6]; +}; +\end{lstlisting} + +The VIRTIO_TRANSPTQ_CTRL_VQ_ADDR_SET command is used to set the addresses of a specified +virtqueue. The command-out-data contains the \field{queue_index}, the addresses of \field{device_area}, +\field{descriptor_area} and \field{driver_area} (as described in struct +virtio_transportq_ctrl_vq_addr). There's no command-in-data. + +\devicenormative{\subsubsection}{Virtqueue Address}{Virtio Transport Options / Virtio +Over Transport Virtqueue / Virtqueeu Address} + +The management device MUST fail the commands of class +VIRTIO_TRANSPTQ_CTRL_VQ_ADDR if \field{device_id} is 0. + +The management device MUST fail the commands of class +VIRTIO_TRANSPTQ_CTRL_VQ_ADDR if \field{queue_index} is out-of-range invalid. + +\subsection{Virtqueue Status}\label{sec:Virtio Transport Options / Virtio Over +Transport Virtqueue / Virtqueue Status} + +When VIRTIO_F_TRANSPT_VQ is negotiated with the management device, +virtqueue status is accessed through the following command: + +\begin{lstlisting} +#define VIRTIO_TRANSPTQ_CTRL_VQ_ENABLE 9 + #define VIRTIO_TRANSPTQ_CTRL_VQ_ENABLE_GET 0 + #define VIRTIO_TRANSPTQ_CTRL_VQ_ENABLE_SET 1 + +struct virtio_transportq_ctrl_vq_status_set { + u16 queue_index; + u8 status; + u8 padding[5]; + +#define VIRTIO_TRANSPTQ_VQ_ENABLE 1 +#define VIRTIO_TRANSPTQ_VQ_DISABLE 0 + +}; + +\end{lstlisting} + +The VIRTIO_TRANSPTQ_CTRL_VQ_ENABLE_GET is used to get the status of a +specific virtqueue. The command-out-data is the queue +index. The command-in-data is the virtqueue status. + +The VIRTIO_TRANSPTQ_CTRL_VQ_ENABLE_SET command is used to set the status of a +specific virtqueue. The command-out-data is the \field{queue_index} and the +\field{status} representing ENABLE or DISABLE that is set to the virtqueue +(as described in struct virtio_transportq_ctrl_vq_status_set). +There's no command-in-data. + +\devicenormative{\subsubsection}{Virtqueue Status}{Virtio Transport Options / Virtio +Over Transport Virtqueue / Virtqueue Status} + +When disabled, the managed device MUST stop processing requests from +this virtqueue. + +The management device MUST present a 0 via +VIRTIO_TRANSPTQ_CTRL_VQ_ENABLE_GET upon a reset of the managed device. + +The management device MUST fail the virtqueue status access if +\field{device_id} is 0. + +The management device MUST fail the virtqueue status access if +the queue_index is out-of-range invalid. + + +\drivernormative{\subsubsection}{Virtqueue Status}{Virtio Transport Options / Virtio +Over Transport Virtqueue / Virtqueue Status} + +The driver MUST configure other virtqueue fields before enabling +the virtqueue with VIRTIO_TRANSPTQ_CTRL_VQ_ENABLE_SET. + +\subsection{Virtqueue Size}\label{sec:Virtio Transport Options / Virtio Over +Transport Virtqueue / Virtqueue Size} + +When VIRTIO_F_TRANSPT_VQ is negotiated with the management device, +virtqueue size is accessed through the following command: + +\begin{lstlisting} +#define VIRTIO_TRANSPTQ_CTRL_VQ_SIZE 10 + #define VIRTIO_TRANSPTQ_CTRL_VQ_SIZE_GET 0 + #define VIRTIO_TRANSPTQ_CTRL_VQ_SIZE_SET 1 + +struct virtio_transportq_ctrl_vq_size_set { + u16 queue_index; + u16 size; + u8 padding[4]; +}; +\end{lstlisting} + +The VIRTIO_TRANSPTQ_CTRL_VQ_SIZE_GET command is used to get the virtqueue +size. On reset, the maximum queue size supported by the device is +returned. The command-out-data is the queue index. The +command-in-data is an 16-bit queue size. + +The VIRTIO_TRANSPTQ_CTRL_VQ_SIZE_SET command is used to set the virtqueue +size. The command-out-data is the \field{queue_index} and the \field{size} +of the virtqueue (as described in struct virtio_transportq_ctrl_vq_size_set). +There's no command-in-data. + +\devicenormative{\subsubsection}{Virtqueue Status}{Virtio Transport Options / Virtio +Over Transport Virtqueue / Virtqueue Size} + +The management device MUST fail the virtqueue size access if +\field{device_id} is 0. + +The management device MUST fail the virtqueue size access if +the queue index is out-of-range invalid. + +\subsection{Virtqueue Notification}\label{sec:Virtio Transport Options / Virtio +Over Transport Virtqueue / Virtqueue Notification} + +When VIRTIO_F_TRANSPT_VQ is negotiated with the management device, +the virtqueue notification area information can be get through the following commands: + +\begin{lstlisting} +#define VIRTIO_TRANSPTQ_CTRL_VQ_NOTIFY 11 + #define VIRTIO_TRANSPTQ_CTRL_VQ_NOTIFY_GET 0 + +struct virtio_transportq_ctrl_vq_notification_area { + u64 address; + u64 size; +}; +\end{lstlisting} + +The VIRTIO_TRANSPTQ_CTRL_VQ_NOTIFY_GET is used to get the transport +specific address area that can be used to notify a virtqueue. The +command-out-data is an u16 of the queue index. The command-in-data +contains the \field{address} and the \field{size} +of the notification area (as described in struct virtio_transportq_ctrl_vq_notification_area). + +\devicenormative{\subsubsection}{Virtqueue Notification}{Virtio Transport Options / +Virtio Over Transport Virtqueue / Virtqueue Notification} + +The management device MUST fail the virtqueue notification area information +access if \field{device_id} is 0. + +The management device MUST fail the virtqueue notification area information +access if the queue index is out-of-range invalid. + +\drivernormative{\subsubsection}{Virtqueue Notification}{Virtio Transport Options / +Virtio Over Transport Virtqueue / Virtqueue Notification} + +The driver MAY choose to notify the virtqueue by writing the queue +index at address \field{address} which is fetched from the +VIRTIO_TRANSPTQ_CTRL_VQ_NOTIFY_GET command. + +\subsection{Virtqueue State}\label{sec:Virtio Transport Options / Virtio +Over Transport Virtqueue / Virtqueue State} + +When VIRTIO_F_TRANSPT_VQ is negotiated with the management device, +the virtqueue state is accessed through the following commands: + +\begin{lstlisting} +#define VIRTIO_TRANSPTQ_CTRL_VQ_STATE 12 + #define VIRTIO_TRANSPTQ_CTRL_VQ_STATE_GET 0 + #define VIRTIO_TRANSPTQ_CTRL_VQ_STATE_SET 1 +\end{lstlisting} + +\subsubsection{Split Virtqueue State}\label{sec:Virtio Transport Options / Virtio +Over Transport Virtqueue / Virtqueue State / Split Virtqueue State} + +\begin{lstlisting} +struct virtio_transportq_ctrl_split_vq_state_set { + u16 queue_index; + u16 avail_index; + u8 padding[4]; +}; +\end{lstlisting} + +The VIRTIO_TRANSPTQ_CTRL_VQ_STATE_GET command can be used to get the state of a +split virtqueue. The command-out-data is the queue index, the command-in-data is the available index of the virtqueue. + +The VIRTIO_TRANSPTQ_CTRL_VQ_STATE_SET command can be used to set the state of a +split virtqueue. The command-out-data contains the \field{queue_index} and the +available index (\field{avail_index}) for the virtqueue (as described in struct virtio_transportq_ctrl_split_vq_state_set). +There is no command-in-data. + +\subsubsection{Packed Virtqueue State}\label{sec:Virtio Transport Options / Virtio +Over Transport Virtqueue / Virtqueue State / Packed Virtqueue State} + +\begin{lstlisting} +struct virtio_transportq_ctrl_packed_vq_state { + u16 queue_index; + u16 avail_counter; + u16 avail_index; + u16 used_counter; + u16 used_index; + u8 padding[6]; +}; +\end{lstlisting} + +The state of a packed virtqueue includes :\\ +\field{avail_counter}: last driver ring wrap counter observed by device.\\ +\field{avail_index}: virtqueue available index.\\ +\field{used_counter}: device ring wrap counter.\\ +\field{used_index}: virtqueue used index. + +The VIRTIO_TRANSPTQ_CTRL_VQ_STATE_GET command can be used to get the state of a packed virtqueue. +The command-out-data is the queue index, the command-in-data contains the \field{queue_index}, +\field{avail_counter}, \field{avail_index}, \field{used_counter} and \field{used_index} of the virtqueue +(as described in transportq_ctrl_packed_vq_state). + +The VIRTIO_TRANSPTQ_CTRL_VQ_STATE_SET command can be used to set the state of a packed virtqueue. +The command-out-data contains the \field{queue_index}, \field{avail_counter}, \field{avail_index}, +\field{used_counter} and \field{used_index} for the virtqueue +(as described in transportq_ctrl_packed_vq_state). +There is no command-in-data. + +\devicenormative{\subsubsection}{Virtqueue State}{Virtio Transport Options / +Virtio Over Transport Virtqueue / Virtqueue State} + +The management device MUST fail the virtqueue index access if \field{device_id} is 0. + +The management device MUST fail the virtqueue index access if \field{queue_index} is out-of-range invalid. + +\subsection{Virtqueue ASID}\label{sec:Virtio Transport Options / Virtio Over +Transport Virtqueue / Virtqueue ASID} + +When VIRTIO_F_TRANSPT_VQ is negotiated with the management device, +the address space id of a virtqueue could be set through the following command: + +\begin{lstlisting} +#define VIRTIO_TRANSPTQ_CTRL_VQ_ASID 13 + #define VIRTIO_TRANSPTQ_CTRL_VQ_ASID_SET 1 + +struct virtio_transportq_ctrl_vq_asid_set { + u16 queue_index; + u32 asid; + u8 padding[2]; +}; +\end{lstlisting} + +The VIRTIO_TRANSPTQ_CTRL_VQ_ASID_SET command is used to set the address space id(\field{asid}) +of a virtqueue. + +The address space id is an identifier of a memory space which is used to convey the address space targeted by the +memory accesses, and to distinguish memory accesses performed by different virtqueues + +One example of the address space id is PASID (Process Address Space Identifier) which is +defined in \hyperref[intro:PCIe]{[PCIe]} specification. + +The command-out-data of VIRTIO_TRANSPTQ_CTRL_VQ_ASID_SET command is the \field{queue_index} +and the address space id (\field{asid}). +(as described in struct virtio_transportq_ctrl_vq_asid_set). + +\devicenormative{\subsubsection}{Virtqueue ASID}{Virtio Transport Options / +Virtio Over Transport Virtqueue / Virtqueue ASID} + +Once a virtqueue has been set an asid, it MUST perform any memory accesses with the asid. + +The management device MUST fail the virtqueue index access if \field{device_id} is 0. + +The management device MUST fail the virtqueue index access if \field{queue_index} is out-of-range invalid. + +\subsection{Virtqueue Reset}\label{sec:Virtio Transport Options / Virtio Over +Transport Virtqueue / Virtqueue Reset} + +When VIRTIO_F_TRANSPT_VQ is negotiated with the management device, +a virtqueue can be reset through the following command: + +\begin{lstlisting} +#define VIRTIO_TRANSPTQ_CTRL_VQ_RESET 14 + #define VIRTIO_TRANSPTQ_CTRL_VQ_DO_RESET 1 +\end{lstlisting} + +The VIRTIO_TRANSPTQ_CTRL_VQ_DO_RESET command is used to reset a virtqueue. +The command-out-data is the virtqueue index, there is no command-in-data. + +\devicenormative{\subsubsection}{Virtqueue Reset}{Virtio Transport Options / +Virtio Over Transport Virtqueue / Virtqueue Reset} + +The management device MUST fail VIRTIO_TRANSPTQ_CTRL_VQ_RESET if +\field{device_id} is 0. + +The management device MUST fail VIRTIO_TRANSPTQ_CTRL_VQ_RESET if +the virtqueue index is out-of-range invalid. + +The managed device MUST stop consuming the descriptors in the virtqueue once reset it. + +The managed device MUST present default states of a virtqueue after reset it. + +\drivernormative{\subsubsection}{Virtqueue Reset}{Virtio Transport Options / +Virtio Over Transport Virtqueue / Virtqueue Reset} + +After reseting a virtqueue, the driver MUST wait until the reset is successfully +done (by verifying virtio_transportq_ctrl.ack == VIRTIO_TRANSPTQ_OK) +before re-enabling it. \chapter{Device Types}\label{sec:Device Types} -- 2.35.3
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