virtio — archive

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

On Thu, Nov 24, 2022 at 03:42:18PM +0800, Jason Wang wrote: > On Thu, Nov 24, 2022 at 3:12 PM Michael S. Tsirkin <mst@redhat.com> wrote: > > > > On Thu, Nov 24, 2022 at 01:52:41PM +0800, Jason Wang wrote: > > > On Thu, Nov 24, 2022 at 5:08 AM Michael S. Tsirkin <mst@redhat.com> wrote: > > > > > > > > This introduces a general structure for group administration commands, > > > > used to control device groups through their owner. > > > > > > > > Following patches will introduce specific commands and an interface for > > > > submitting these commands to the owner. > > > > > > > > Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com> > > > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > > > > --- > > > > admin.tex | 98 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > > > 1 file changed, 98 insertions(+) > > > > > > > > diff --git a/admin.tex b/admin.tex > > > > index 6ebdd05..1dca136 100644 > > > > --- a/admin.tex > > > > +++ b/admin.tex > > > > @@ -42,4 +42,102 @@ \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 / Device groups / Group administration commands} > > > > > > > > +Group administration commands can be issued through an owner > > > > +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. > > > > > > This excludes any possible runtime configuration, is this intended? > > > > No idea - what kind of runtime configuration are you talking about? > > This explicitly says "to configure a member device" and that's > > certainly at runtime. > > Not sure, but if we say something like we, it means we need a group of > commands to support runtime stuff in the future? we'll need commands to provision members - is this what you mean? for sure. > > > > > > > > > > > + > > > > +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_type; > > > > + /* unused, reserved for future extensions */ > > > > + u8 reserved1[12]; > > > > + le64 group_member_id; > > > > + u8 command_specific_data[]; > > > > + > > > > + /* Device-writable part */ > > > > + le16 status; > > > > + le16 status_qualifier; > > > > + /* unused, reserved for future extensions */ > > > > + u8 reserved2[4]; > > > > + u8 command_specific_result[]; > > > > +}; > > > > +\end{lstlisting} > > > > + > > > > +For all commands, \field{opcode}, \field{group_type} and if > > > > +necessary \field{group_member_id} and \field{command_specific_data} are > > > > +set by the driver, and the owner device sets \field{status} and if > > > > +needed \field{status_qualifier} 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 & Name & Command Description \\ > > > > +\hline \hline > > > > +0x0000 - 0x7FFF & - & Group administration commands \\ > > > > +\hline > > > > +0x8000 - 0xFFFF & - & Reserved \\ > > > > +\hline > > > > +\end{tabular} > > > > + > > > > +The \field{group_type} specifies the group type identifier. > > > > > > So this means there's no way for having a group specific adminq? E.g > > > one queue for SR-IOV and another for SIOV. > > > > > > > +The \field{group_member_id} specifies the member identifier within the group. > > > > +See section \ref{sec:Introduction / Terminology / Device group} > > > > +for the definition of the group type identifier and group member > > > > +identifier. > > > > + > > > > +The following table describes possible \field{status} values; > > > > +to simplify common implementations, they are intentionally > > > > +matching common Linux names and error numbers: > > > > > > I may miss something but I don't see how it matches Linux error numbers. > > > > > > include/uapi/asm-generic/errno-base.h:#define EINVAL 22 /* Invalid argument */ > > Ok, only this one was matched but any advantages of menting the > matching? I believe not all the error numbers are meaningful for a > device interface (e.g EINTR). > > Thanks Makes it easier for driver to decide on an error to report to userspace. If we don't use all error codes that's fine. > > > > > > > Thanks > > > > > > > + > > > > +\begin{tabular}{|l|l|l|} > > > > +\hline > > > > +Status (decimal) & Name & Description \\ > > > > +\hline \hline > > > > +00 & VIRTIO_ADMIN_STATUS_OK & successful completion \\ > > > > +\hline > > > > +22 & VIRTIO_ADMIN_STATUS_EINVAL & invalid command \\ > > > > +\hline > > > > +other & - & group administration command error \\ > > > > +\hline > > > > +\end{tabular} > > > > + > > > > +When \field{status} is VIRTIO_ADMIN_STATUS_OK, \field{status_qialifier} > > > > +is reserved and set to zero by the device. > > > > + > > > > +When \field{status} is VIRTIO_ADMIN_STATUS_EINVAL, > > > > +the following table describes possible \field{status_qialifier} values: > > > > +\begin{tabular}{|l|l|l|} > > > > +\hline > > > > +Status & Name & Description \\ > > > > +\hline \hline > > > > +0x00 & VIRTIO_ADMIN_STATUS_Q_INVALID_COMMAND & command error: no additional information \\ > > > > +\hline > > > > +0x01 & VIRTIO_ADMIN_STATUS_Q_INVALID_OPCODE & unsupported or invalid \field{opcode} \\ > > > > +\hline > > > > +0x02 & VIRTIO_ADMIN_STATUS_Q_INVALID_FIELD & unsupported or invalid field within \field{command_specific_data} \\ > > > > +\hline > > > > +0x03 & VIRTIO_ADMIN_STATUS_Q_INVALID_GROUP & unsupported or invalid \field{group_type} \\ > > > > +\hline > > > > +0x04 & VIRTIO_ADMIN_STATUS_Q_INVALID_MEM & unsupported or invalid \field{group_member_id} \\ > > > > +\hline > > > > +0x05-0xFFFF & - & reserved for future use \\ > > > > +\hline > > > > +\end{tabular} > > > > -- > > > > MST > > > > > >