=encoding utf8

=head1 NAME

xl-pci-configuration - XL PCI Configuration Syntax

=head1 SYNTAX

This document specifies the format for B<BDF> and B<PCI_SPEC_STRING> which are
used by the L<xl.cfg(5)> pci configuration option, and related L<xl(1)>
commands.

A B<BDF> has the following form:

    [DDDD:]BB:SS.F

B<DDDD> is the domain number, B<BB> is the bus number, B<SS> is the device (or
slot) number, and B<F> is the function number. This is the same scheme as
used in the output of L<lspci(1)> for the device in question. By default
L<lspci(1)> will omit the domain (B<DDDD>) if it is zero and hence a zero
value for domain may also be omitted when specifying a B<BDF>.

Each B<PCI_SPEC_STRING> has the one of the forms:

=over 4

    [<bdf>[@<vslot>,][<key>=<value>,]*
    [<key>=<value>,]*

=back

For example, these strings are equivalent:

=over 4

    36:00.0@20,seize=1
    36:00.0,vslot=20,seize=1
    bdf=36:00.0,vslot=20,seize=1

=back

More formally, the string is a series of comma-separated keyword/value
pairs, flags and positional parameters.  Parameters which are not bare
keywords and which do not contain "=" symbols are assigned to the
positional parameters, in the order specified below.  The positional
parameters may also be specified by name.

Each parameter may be specified at most once, either as a positional
parameter or a named parameter.  Default values apply if the parameter
is not specified, or if it is specified with an empty value (whether
positionally or explicitly).

B<NOTE>: In context of B<xl pci-detach> (see L<xl(1)>), parameters other than
B<bdf> or B<name> will be ignored.

=head1 Positional Parameters

=over 4

=item B<bdf>=I<BDF>

=over 4

=item Description

This identifies the PCI device from the host perspective.

In the context of a B<PCI_SPEC_STRING> you may specify the function (B<F>) as
B<*> to indicate all functions of a multi-function device.

=item Default Value

None. This parameter is mandatory in its positional form. As a non-positional
parameter it is also mandatory unless a B<name> parameter is present, in
which case B<bdf> must not be present since the B<name> will be used to find
the B<bdf> in the list of assignable devices. See L<xl(1)> for more information
on naming assignable devices.

=back

=item B<vslot>=I<NUMBER>

=over 4

=item Description

Specifies the virtual slot (device) number where the guest will see this
device. For example, running L<lspci(1)> in a Linux guest where B<vslot>
was specified as C<8> would identify the device as C<00:08.0>. Virtual domain
and bus numbers are always 0.

B<NOTE:> This parameter is always parsed as a hexadecimal value.

=item Default Value

None. This parameter is not mandatory. An available B<vslot> will be selected
if this parameter is not specified.

=back

=back

=head1 Other Parameters and Flags

=over 4

=item B<permissive>=I<BOOLEAN>

=over 4

=item Description

By default pciback only allows PV guests to write "known safe" values
into PCI configuration space, likewise QEMU (both qemu-xen and
qemu-xen-traditional) imposes the same constraint on HVM guests.
However, many devices require writes to other areas of the configuration space
in order to operate properly.  This option tells the backend (pciback or QEMU)
to allow all writes to the PCI configuration space of this device by this
domain.

B<This option should be enabled with caution:> it gives the guest much
more control over the device, which may have security or stability
implications.  It is recommended to only enable this option for
trusted VMs under administrator's control.

=item Default Value

0

=back

=item B<msitranslate>=I<BOOLEAN>

=over 4

=item Description

Specifies that MSI-INTx translation should be turned on for the PCI
device. When enabled, MSI-INTx translation will always enable MSI on
the PCI device regardless of whether the guest uses INTx or MSI.

=item Default Value

Some device drivers, such as NVIDIA's, detect an inconsistency and do not
function when this option is enabled. Therefore the default is false (0).

=back

=item B<seize>=I<BOOLEAN>

=over 4

=item Description

Tells L<xl(1)> to automatically attempt to make the device assignable to
guests if that has not already been done by the B<pci-assignable-add>
command.

B<WARNING:> If you set this option, L<xl> will gladly re-assign a critical
system device, such as a network or a disk controller being used by
dom0 without confirmation.  Please use with care.

=item Default Value

0

=back

=item B<power_mgmt>=I<BOOLEAN>

=over 4

=item Description

B<(HVM only)> Specifies that the VM should be able to program the
D0-D3hot power management states for the PCI device.

=item Default Value

0

=back

=item B<rdm_policy>=I<STRING>

=over 4

=item Description

B<(HVM/x86 only)> This is the same as the policy setting inside the B<rdm>
option in L<xl.cfg(5)> but just specific to a given device.

B<NOTE>: This overrides the global B<rdm> option.

=item Default Value

"strict"

=back

=item B<name>=I<STRING>

=over 4

=item Description

This is the name given when the B<BDF> was made assignable. See L<xl(1)> for
more information on naming assignable devices.

=item Default Value

None. This parameter must not be present if a B<bdf> parameter is present.
If a B<bdf> parameter is not present then B<name> is mandatory as it is
required to look up the B<BDF> in the list of assignable devices.

=back

=back
