From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Date: Thu, 18 Aug 2022 04:51:35 -0400 From: "Michael S. Tsirkin" Message-ID: <20220818044918-mutt-send-email-mst@kernel.org> References: <20220812171841.12183-1-mst@redhat.com> <20220812171841.12183-3-mst@redhat.com> MIME-Version: 1.0 In-Reply-To: Subject: [virtio] Re: [PATCH RFC v7 2/8] Introduce group administration commands 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 04:46:45PM +0800, Jason Wang wrote: > On Sat, Aug 13, 2022 at 1:19 AM Michael S. Tsirkin wrote: > > > > From: Max Gurtovoy > > > > 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 > > Signed-off-by: Michael S. Tsirkin > > --- > > 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. > > This part should go with patch 1? > > > \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; > > I wonder about the implication of this field. Does it mean: > > 1) a single admin virtqueue that manage two group of VFs > > or > > 2) a single admin virtqueue that manages both VFs and SFs (then > 'group_type' should be better?) > > If it's 1, the group id seems not sufficient. If it's 2, I wonder if > it scales (using a single admin virtqueue to manage both VF and SF). > > Thanks 2 at the moment. Not sure I understand why wouldn't it scale. I don't see a fundamental difference between 1 or 2 VQs. We are not going to be adding 1000s of them, > > + /* 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 > > --------------------------------------------------------------------- To unsubscribe from this mail list, you must leave the OASIS TC that generates this mail. Follow this link to all your TCs in OASIS at: https://www.oasis-open.org/apps/org/workgroup/portal/my_workgroups.php