virtio — archive

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

On Fri, Mar 10, 2023 at 05:10:48PM +0800, Zhu, Lingshan wrote: > > > On 3/2/2023 9:05 PM, Michael S. Tsirkin wrote: > > Add conformance clauses for admin commands and admin virtqueues. > > > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > > --- > > admin.tex 216 +++++++++++++++++++++++++++++++++++++++++++++++++++++- > > 1 file changed, 215 insertions(+), 1 deletion(-) > > > > diff --git a/admin.tex b/admin.tex > > index 1172054..6c4f79c 100644 > > --- a/admin.tex > > +++ b/admin.tex > > @@ -251,6 +251,145 @@ subsection{Group administration commands}label{sec:Basic Facilities of a Virti > > supporting multiple group types, the list of supported commands > > might differ between different group types. > > +devicenormative{paragraph}{Group administration commands}{Basic Facilities of a Virtio Device / Device groups / Group administration commands} > > + > > +The device MUST validate field{opcode}, field{group_type} and > > +field{group_member_id}, and if any of these has an invalid or > > +unsupported value, set field{status} to > > +VIRTIO_ADMIN_STATUS_EINVAL and set field{status_qualifier} > > +accordingly: > > +egin{itemize} > > +item if field{group_type} is invalid, field{status_qualifier} > > + MUST be set to VIRTIO_ADMIN_STATUS_Q_INVALID_GROUP; > > +item otherwise, if field{opcode} is invalid, > > + field{status_qualifier} MUST be set to > > + VIRTIO_ADMIN_STATUS_Q_INVALID_OPCODE; > > +item otherwise, if field{group_member_id} is used by the > > + specific command and is invalid, field{status_qualifier} MUST be > > + set to VIRTIO_ADMIN_STATUS_Q_INVALID_MEMBER. > > +end{itemize} > > + > > +If a command completes successfully, the device MUST set > > +field{status} to VIRTIO_ADMIN_STATUS_OK. > > + > > +If a command fails, the device MUST set > > +field{status} to a value different from VIRTIO_ADMIN_STATUS_OK. > > + > > +If field{status} is set to VIRTIO_ADMIN_STATUS_EINVAL, the > > +device state MUST NOT change, that is the command MUST NOT have > > +any side effects on the device, in particular the device MUST not > > +enter an error state as a result of this command. > > + > > +If a command fails, the device state generally SHOULD NOT change, > > +as far as possible. > > + > > +The device MAY enforce additional restrictions and dependencies on > > +opcodes used by the driver and MAY fail the command > > +VIRTIO_ADMIN_CMD_LIST_USE with field{status} set to VIRTIO_ADMIN_STATUS_EINVAL > > +and field{status_qualifier} set to VIRTIO_ADMIN_STATUS_Q_INVALID_FIELD > > +if the list of commands used violate internal device dependencies. > > + > > +If the device supports multiple group types, commands for each group > > +type MUST operate independently of each other, in particular, > > +the device MAY return different results for VIRTIO_ADMIN_CMD_LIST_QUERY > > +for different group types. > > + > > +After reset, if the device supports a given group type > > +and before receiving VIRTIO_ADMIN_CMD_LIST_USE for this group type > > +the device MUST assume > > +that the list of legal commands used by the driver consists of > > +the two commands VIRTIO_ADMIN_CMD_LIST_QUERY and VIRTIO_ADMIN_CMD_LIST_USE. > > + > > +After completing VIRTIO_ADMIN_CMD_LIST_USE successfully, > > +the device MUST set the list of legal commands used by the driver > > +to the one supplied in field{command_specific_data}. > > + > > +The device MUST set the list of legal commands used by the driver > > +to the one supplied in VIRTIO_ADMIN_CMD_LIST_USE. > > + > > +The device MUST validate commands against the list used by > > +the driver and MUST fail any commands not in the list with > > +field{status} set to VIRTIO_ADMIN_STATUS_EINVAL > > +and field{status_qualifier} set to > > +VIRTIO_ADMIN_STATUS_Q_INVALID_OPCODE. > > + > > +The list of supported commands MUST NOT shrink (but MAY expand): > > +after reporting a given command as supported through > > +VIRTIO_ADMIN_CMD_LIST_QUERY the device MUST NOT later report it > > +as unsupported. Further, after a given set of commands has been > Can the driver re-negotiate the command list through QUERY/USE > in flight rather than upon a reset? If not, shall forbid this explicitly? > > +used (via a successful VIRTIO_ADMIN_CMD_LIST_USE), then after a > > +device or system reset the device SHOULD complete successfully > > +any following calls to VIRTIO_ADMIN_CMD_LIST_USE with the same > > +list of commands; if this command VIRTIO_ADMIN_CMD_LIST_USE fails > I think this requires the device to remember what it had offered even > after a power-cycled reset, It just says always return the same. > shall we say: The device should always offer all > supported > commands in the list? I don't see what will it mean. > Thanks, > Zhu Lingshan > > +after a device or system reset, the device MUST not fail it > > +solely because of the command list used. Failure to do so would > > +interfere with resuming from suspend and error recovery. > > + > > +When processing a command with the SR-IOV group type, > > +if the device does not have an SR-IOV Extended Capability or > > +if field{VF Enable} is clear > > +then the device MUST fail all commands with > > +field{status} set to VIRTIO_ADMIN_STATUS_EINVAL and > > +field{status_qualifier} set to > > +VIRTIO_ADMIN_STATUS_Q_INVALID_GROUP; > > +otherwise, if field{group_member_id} is not > > +between $1$ and field{NumVFs} inclusive, > > +the device MUST fail all commands with > > +field{status} set to VIRTIO_ADMIN_STATUS_EINVAL and > > +field{status_qualifier} set to > > +VIRTIO_ADMIN_STATUS_Q_INVALID_MEMBER; > > +field{NumVFs}, field{VF Migration Capable} and > > +field{VF Enable} refer to registers within the SR-IOV Extended > > +Capability as specified by hyperref[intro:PCIe]{[PCIe]}. > > + > > +drivernormative{paragraph}{Group administration commands}{Basic Facilities of a Virtio Device / Device groups / Group administration commands} > > + > > +The driver MAY discover whether device supports a specific group type > > +by issuing VIRTIO_ADMIN_CMD_LIST_QUERY with the matching > > +field{group_type}. > > + > > +The driver MUST issue VIRTIO_ADMIN_CMD_LIST_USE > > +and wait for it to be completed with status > > +VIRTIO_ADMIN_STATUS_OK before issuing any commands > > +(except for the initial VIRTIO_ADMIN_CMD_LIST_QUERY > > +and VIRTIO_ADMIN_CMD_LIST_USE). > > + > > +The driver SHOULD NOT set bits in device_admin_cmds > > +if it is not familiar with how the command opcode > > +is used, as dependencies between command opcodes might exist. > > + > > +The driver MUST NOT request (via VIRTIO_ADMIN_CMD_LIST_USE) > > +the use of any commands not previously reported as > > +supported for the same group type by VIRTIO_ADMIN_CMD_LIST_QUERY. > > + > > +The driver MUST NOT use any commands for a given group type > > +before sending VIRTIO_ADMIN_CMD_LIST_USE with the correct > > +list of command opcodes and group type. > > + > > +The driver MAY block use of VIRTIO_ADMIN_CMD_LIST_QUERY and > > +VIRTIO_ADMIN_CMD_LIST_USE by issuing VIRTIO_ADMIN_CMD_LIST_USE > > +with respective bits cleared in field{command_specific_data}. > > + > > +The driver MUST handle a command error with a reserved field{status} > > +value in the same way as field{status} set to VIRTIO_ADMIN_STATUS_EINVAL > > +(except possibly for different error reporting/diagnostic messages). > > + > > +The driver MUST handle a command error with a reserved > > +field{status_qualifier} value in the same way as > > +field{status_qualifier} set to > > +VIRTIO_ADMIN_STATUS_Q_INVALID_COMMAND (except possibly for > > +different error reporting/diagnostic messages). > > + > > +When sending commands with the SR-IOV group type, > > +the driver specify a value for field{group_member_id} > > +between $1$ and field{NumVFs} inclusive, > > +the driver MUST also make sure that as long as any such command > > +is outstanding, field{VF Migration Capable} is clear and > > +field{VF Enable} is set; > > +field{NumVFs}, field{VF Migration Capable} and > > +field{VF Enable} refer to registers within the SR-IOV Extended > > +Capability as specified by hyperref[intro:PCIe]{[PCIe]}. > > + > > section{Administration Virtqueues}label{sec:Basic Facilities of a Virtio Device / Administration Virtqueues} > > An administration virtqueue of an owner device is used to submit > > @@ -323,4 +462,79 @@ section{Administration Virtqueues}label{sec:Basic Facilities of a Virtio Devic > > of the specification are designed, new fields can be added to the > > tail of a structure, with the driver/device using the full > > structure without concern for versioning. > > ->>>>>>> 0edc690... admin: introduce virtio admin virtqueues > > + > > +devicenormative{paragraph}{Group administration commands}{Basic Facilities of a Virtio Device / Administration virtqueues} > > + > > +The device MUST support device-readable and device-writeable buffers > > +shorter than described in this specification, by > > +egin{enumerate} > > +item acting as if any data that would be read outside the > > +device-readable buffers is set to zero, and > > +item discarding data that would be written outside the > > +specified device-writeable buffers. > > +end{enumerate} > > + > > +The device MUST support device-readable and device-writeable buffers > > +longer than described in this specification, by > > +egin{enumerate} > > +item ignoring any data in device-readable buffers outside > > +the expected length, and > > +item only writing the expected structure to the device-writeable > > +buffers, ignoring any extra buffers, and reporting the > > +actual length of data written, in bytes, > > +as buffer used length. > > +end{enumerate} > > + > > +The device SHOULD initialize the device-writeable buffer > > +up to the length of the structure described by this specification or > > +the length of the buffer supplied by the driver (even if the buffer is > > +all set to zero), whichever is shorter. > > + > > +The device MUST NOT fail a command solely because the buffers > > +provided are shorter or longer than described in this > > +specification. > > + > > +The device MUST initialize the device-writeable part of > > +field{struct virtio_admin_cmd} that is a multiple of 64 bit in > > +size. > > + > > +The device MUST initialize field{status} in field{struct > > +virtio_admin_cmd}. > > + > > +The device MUST process commands on a given administration virtqueue > > +in the order in which they are queued. > > + > > +If multiple administration virtqueues have been configured, > > +device MAY process commands on distinct virtqueues with > > +no order constraints. > > + > > +drivernormative{paragraph}{Group administration commands}{Basic Facilities of a Virtio Device / Administration virtqueues} > > + > > +The driver MAY supply device-readable or device-writeable parts > > +of field{struct virtio_admin_cmd} that are longer than described in > > +this specification. > > + > > +The driver SHOULD supply device-readable part of > > +field{struct virtio_admin_cmd} that is at least as > > +large as the structure described by this specification > > +(even if the structure is all set to zero). > > + > > +The driver MUST supply both device-readable or device-writeable parts > > +of field{struct virtio_admin_cmd} that are a multiple of 64 bit > > +in length. > > + > > +The device MUST supply both device-readable or device-writeable parts > > +of field{struct virtio_admin_cmd} that are larger than zero in > > +length. However, field{command_specific_data} and > > +field{command_specific_result} MAY be zero in length, unless > > +specified otherwise for the command. > > + > > +The driver MUST NOT assume that the device will initialize the whole > > +device-writeable part of field{struct virtio_admin_cmd} as described in the specification; instead, > > +the driver MUST act as if the structure > > +outside the part of the buffer used by the device > > +is set to zero. > > + > > +If multiple administration virtqueues have been configured, > > +the driver MUST ensure ordering for commands > > +placed on different administration virtqueues.