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.Dd May 28, 2015
.Dt pci_iov_schema 9
.Os
.Sh NAME
.Nm pci_iov_schema ,
.Nm pci_iov_schema_alloc_node ,
.Nm pci_iov_schema_add_bool ,
.Nm pci_iov_schema_add_string ,
.Nm pci_iov_schema_add_uint8 ,
.Nm pci_iov_schema_add_uint16 ,
.Nm pci_iov_schema_add_uint32 ,
.Nm pci_iov_schema_add_uint64 ,
.Nm pci_iov_schema_add_unicast_mac
.Nd PCI SR-IOV config schema interface
.Sh SYNOPSIS
.In machine/stdarg.h
.In sys/nv.h
.In sys/iov_schema.h
.Ft nvlist_t *
.Fn pci_iov_schema_alloc_node "void"
.Ft void
.Fn pci_iov_schema_add_bool "nvlist_t *schema" "const char *name" \
"uint32_t flags" "int defaultVal"
.Ft void
.Fn pci_iov_schema_add_string "nvlist_t *schema" "const char *name" \
"uint32_t flags" "const char *defaultVal"
.Ft void
.Fn pci_iov_schema_add_uint8 "nvlist_t *schema" "const char *name" \
"uint32_t flags" "uint8_t defaultVal"
.Ft void
.Fn pci_iov_schema_add_uint16 "nvlist_t *schema" "const char *name" \
"uint32_t flags" "uint16_t defaultVal"
.Ft void
.Fn pci_iov_schema_add_uint32 "nvlist_t *schema" "const char *name" \
"uint32_t flags" "uint32_t defaultVal"
.Ft void
.Fn pci_iov_schema_add_uint64 "nvlist_t *schema" "const char *name" \
"uint32_t flags" "uint64_t defaultVal"
.Ft void
.Fn pci_iov_schema_add_unicast_mac "nvlist_t *schema" "const char *name" \
"uint32_t flags" "const uint8_t *defaultVal"
.Sh DESCRIPTION
The PCI Single-Root I/O Virtualization 
.Pq SR-IOV
configuration schema is a data
structure that describes the device-specific configuration parameters that a PF
driver will accept when SR-IOV is enabled on the PF device.
Each PF driver defines two schema instances: the PF schema and the VF schema.
The PF schema describes configuration that applies to the PF device as a whole.
The VF schema describes configuration that applies to an individual VF device.
Different VF devices may have different configuration applied to them, as long
as the configuration for each VF conforms to the VF schema.
.Pp
A PF driver builds a configuration schema by first allocating a schema node and
then adding configuration parameter specifications to the schema.
The configuration parameter specification consists of a name and a value type.
.Pp
Configuration parameter names are case-insensitive.
It is an error to specify two or more configuration parameters with the same
name.
It is also an error to specific a configuration parameter that uses the same
name as a configuration parameter used by the SR-IOV infrastructure.
See
.Xr iovctl.conf 5
for documentation of all configuration parameters used by the SR-IOV
infrastructure.
.Pp
The parameter type constrains the possible values that the configuration
parameter may take.
.Pp
A configuration parameter may be specified as a required parameter by setting
the
.Dv IOV_SCHEMA_REQUIRED
flag in the
.Pa flags
argument.
Required parameters must be specified by the user when SR-IOV is enabled.
If the user does not specify a required parameter, the SR-IOV infrastructure
will abort the request to enable SR-IOV and return an error to the user.
.Pp
Alternatively, a configuration parameter may be given a default value by
setting the
.Dv IOV_SCHEMA_HASDEFAULT
flag in the
.Pa flags
argument.
If a configuration parameter has a default value but the user has not specified
a value for that parameter, then the SR-IOV infrastructure will apply
.Pa defaultVal
for that parameter in the configuration before passing it to the PF driver.
It is an error for the value of the
.Pa defaultVal
parameter to not conform to the restrictions of the specified type.
If this flag is not specified then the
.Pa defaultVal
argument is ignored.
This flag is not compatible with the
.Dv IOV_SCHEMA_REQUIRED
flag; it is an error to specify both on the same parameter.
.Pp
The SR-IOV infrastructure guarantees that all configuration parameters that are
either specified as required or given a default value will be present in the
configuration passed to the PF driver.
Configuration parameters that are neither specified as required nor given a
default value are optional and may or may not be present in the configuration
passed to the PF driver.
.Pp
It is highly recommended that a PF driver reserve the use of optional parameters
for configuration that is truly optional.
For example, a Network Interface PF device might have the option to encapsulate
all traffic to and from a VF device in a vlan tag.
The PF driver could expose that option as a "vlan" parameter accepting an
integer argument specifying the vlan tag.
In this case, it would be appropriate to set the "vlan" parameter as an optional
parameter as it would be legitimate for a VF to be configured to have no vlan
tagging enabled at all.
.Pp
Alternatively, if the PF device had an boolean option that controlled whether
the VF was allowed to change its MAC address, it would not be appropriate to
set this parameter as optional.
The PF driver must either allow the MAC to change or not, so it would be more
appropriate for the PF driver to document the default behaviour by specifying
a default value in the schema 
.Po or potentially force the user to make the choice by setting the parameter
to be required 
.Pc .
.Pp
Configuration parameters that have security implications must default to the
most secure configuration possible.
.Pp
All device-specific configuration parameters must be documented in the manual
page for the PF driver, or in a separate manual page that is cross-referenced
from the main driver manual page.
.Pp
It is not necessary for a PF driver to check for failure from any of these
functions.
If an error occurs, it is flagged in the schema.
The
.Xr pci_iov_attach 9
function checks for this error and will fail to initialize SR-IOV on the PF
device if an error is set in the schema.
If this occurs, it is recommended that the PF driver still succeed in attaching
and run with SR-IOV disabled on the device.
.Pp
The
.Fn pci_iov_schema_alloc_node
function is used to allocate an empty configuration schema.
It is not necessary to check for failure from this function.
The SR-IOV infrastructure will gracefully handle failure to allocate a schema
and will simply not enable SR-IOV on the PF device.
.Pp
The
.Fn pci_iov_schema_add_bool
function is used to specify a configuration parameter in the given schema with
the name
.Pa name
and having a boolean type.
Boolean values can only take the value true or false (1 or 0, respectively).
.Pp
The
.Fn pci_iov_schema_add_string
function is used to specify a configuration parameter in the given schema with
the name
.Pa name
and having a string type.
String values are standard C strings.
.Pp
The
.Fn pci_iov_schema_add_uint8
function is used to specify a configuration parameter in the given schema with
the name
.Pa name
and having a
.Vt uint8_t
type.
Values of type
.Vt uint8_t
are unsigned integers in the range 0 to 255, inclusive.
.Pp
The
.Fn pci_iov_schema_add_uint16
function is used to specify a configuration parameter in the given schema with
the name
.Pa name
and having a
.Vt uint16_t
type.
Values of type
.Vt uint16_t
are unsigned integers in the range 0 to 65535, inclusive.
.Pp
The
.Fn pci_iov_schema_add_uint32
function is used to specify a configuration parameter in the given schema with
the name
.Pa name
and having a
.Vt uint32_t
type.
Values of type
.Vt uint32_t
are unsigned integers in the range 0 to 
.Po 2**32 - 1 Pc ,
inclusive.
.Pp
The
.Fn pci_iov_schema_add_uint64
function is used to specify a configuration parameter in the given schema with
the name
.Pa name
and having a
.Vt uint64_t
type.
Values of type
.Vt uint64_t
are unsigned integers in the range 0 to 
.Po 2**64 - 1 Pc ,
inclusive.
.Pp
The
.Fn pci_iov_schema_add_unicast_mac
function is used to specify a configuration parameter in the given schema with
the name
.Pa name
and having a unicast-mac type.
Values of type unicast-mac are binary values exactly 6 bytes long.
The MAC address is guaranteed to not be a multicast or broadcast address.
.Sh RETURN VALUES
The
.Fn pci_iov_schema_alloc_node
function returns a pointer to the allocated schema, or NULL if a failure occurs.
.Sh SEE ALSO
.Xr pci 9 ,
.Xr PCI_IOV_ADD_VF 9 ,
.Xr PCI_IOV_INIT 9
.Sh AUTHORS
This manual page was written by
.An Ryan Stone Aq rstone@FreeBSD.org .