From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 18 Aug 2022 04:54:03 -0400 From: "Michael S. Tsirkin" Subject: Re: [PATCH RFC v7 8/8] admin command list discovery Message-ID: <20220818045246-mutt-send-email-mst@kernel.org> References: <20220812171841.12183-1-mst@redhat.com> <20220812171841.12183-9-mst@redhat.com> MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=us-ascii Content-Disposition: inline To: Jason Wang Cc: virtio-comment@lists.oasis-open.org, Virtio-Dev , Cornelia Huck , Stefano Garzarella , Stefan Hajnoczi , nrupal.jani@intel.com, "Uminski, Piotr" , hang.yuan@intel.com, virtio@lists.oasis-open.org, Zhu Lingshan , Oren Duer , Parav Pandit , Shahaf Shuler , Ariel Adam , eperezma , Max Gurtovoy List-ID: On Thu, Aug 18, 2022 at 04:51:39PM +0800, Jason Wang wrote: > On Sat, Aug 13, 2022 at 1:19 AM Michael S. Tsirkin wrote: > > > > From: Max Gurtovoy > > > > 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. > > Thanks I am not sure these commands are needed. Maybe make do with feature bits for now. But VQs won't solve anything that feature bits won't. > > > > Signed-off-by: Max Gurtovoy > > Signed-off-by: Michael S. Tsirkin > > --- > > 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 > >