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Subject: Re: [virtio-dev] Re: [PATCH RFC v7 8/8] admin command list discovery
On 8/18/2022 4:51 PM, Jason Wang wrote:
On Sat, Aug 13, 2022 at 1:19 AM Michael S. Tsirkin <mst@redhat.com> wrote:From: Max Gurtovoy <mgurtovoy@nvidia.com> Add commands to find out which commands does each group support. This will be useful once we have multiple group types.I still wonder if it's better to just use different types of virtqueues, it seems more simple than this.
Agree!
ThanksSigned-off-by: Max Gurtovoy <mgurtovoy@nvidia.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> --- admin.tex | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 70 insertions(+), 2 deletions(-) diff --git a/admin.tex b/admin.tex index 99b6c2a..5956c48 100644 --- a/admin.tex +++ b/admin.tex @@ -96,9 +96,11 @@ \subsection{Group administration commands}\label{sec:Basic Facilities of a Virti \begin{tabular}{|l|l|} \hline -opcode & Command Description \\ +opcode & Name & Command Description \\ \hline \hline -0000h - 7FFFh & Group administration commands \\ +0000h & VIRTIO_ADMIN_CMD_LIST_QUERY & Provides to driver list of commands supported for this group type \\ +0001h & VIRTIO_ADMIN_CMD_LIST_ACCEPT & Provides to device list of commands used for this group type \\ +0002h - 7FFFh & - & Group administration commands \\ \hline 8000h - FFFFh & Reserved \\ \hline @@ -142,6 +144,72 @@ \subsection{Group administration commands}\label{sec:Basic Facilities of a Virti structures to the shorter of the two (submitted by driver and described in this specification). +Before sending any other commands for any member of a specific +group to the device, the driver issues the commands +VIRTIO_ADMIN_CMD_LIST_QUERY and VIRTIO_ADMIN_CMD_LIST_ACCEPT. + + +Commands VIRTIO_ADMIN_CMD_LIST_QUERY and VIRTIO_ADMIN_CMD_LIST_ACCEPT +both use the following structure describing the +command opcodes: + +\begin{lstlisting} +struct virtio_admin_cmd_list { + /* Indicates which of the below fields were returned + le32 device_admin_cmds[]; +}; +\end{lstlisting} + +This structure is an array of 32 bit values in little-endian byte +order, in which a bit is set if the specific command opcode +is supported. For example, the array of size 2 including +the values 0x3 and 0x1 indicates that only opcodes 0, 1 and 32 +are supported. + +Accordingly, bits 0 and 1 corresponding to opcode 0 +(VIRTIO_ADMIN_CMD_LIST_QUERY) and 1 (VIRTIO_ADMIN_CMD_LIST_ACCEPT) must +always be set in \field{device_admin_cmds}. + + +For the command VIRTIO_ADMIN_CMD_LIST_QUERY, \field{opcode} is set to 0x0. +The \field{group_member_id} is unused. It must be set to zero by driver. +This command has no command specific data. +The device, upon success, returns a result in the format +\field{struct virtio_admin_cmd_list} describing the +list of administration commands supported for the given group. + + +For the command VIRTIO_ADMIN_CMD_LIST_ACCEPT, \field{opcode} +is set to 0x1. +The \field{group_member_id} is unused. It must be set to zero by driver. +The command specific data is in the format +\field{struct virtio_admin_cmd_list} describing the +list of administration commands used by the driver. +This command has no command specific result. + +The driver issues the command VIRTIO_ADMIN_CMD_LIST_QUERY to +query the list of commands valid for this group. before sending +any commands for any member of a group. + +The driver then accepts some of the opcodes by sending to +the device the command VIRTIO_ADMIN_CMD_LIST_ACCEPT with a subset +of the list returned by VIRTIO_ADMIN_CMD_LIST_QUERY that is +both understood and used by the driver. + +If the device supports the command list used by the driver, the +device completes the command with status VIRTIO_ADMIN_STATUS_OK. +If the device does not support the command list, the device +completes the command with status +VIRTIO_ADMIN_STATUS_INVALID_FIELD. + +Note: drivers SHOULD NOT set bits in device_admin_cmds +if they are not familiar with how the command opcode +is used, since devices MAY have dependencies between +command opcodes. + +It is assumed that all members in a group support and are used +with the same list of commands. + \section{Administration Virtqueue}\label{sec:Basic Facilities of a Virtio Device / Group Administration Virtqueues} An administration virtqueue of a parent device is used to submit -- MST--------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org
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