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PCI: SRIOV control and status via sysfs (documentation)

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Add documentation of new sysfs files and new pci_driver SRIOV
configuration interface.

[bhelgaas: changelog]
Signed-off: Donald Dutile <ddutile@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Donald Dutile
2012-11-27 22:31:37 -05:00
committed by Bjorn Helgaas
parent 1452cd76a9
commit 2597ba763f
2 changed files with 78 additions and 4 deletions
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34
Documentation/ABI/testing/sysfs-bus-pci
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@@ -222,3 +222,37 @@ Description:
satisfied too. Reading this attribute will show the current
value of d3cold_allowed bit. Writing this attribute will set
the value of d3cold_allowed bit.
What: /sys/bus/pci/devices/.../sriov_totalvfs
Date: November 2012
Contact: Donald Dutile <ddutile@redhat.com>
Description:
This file appears when a physical PCIe device supports SR-IOV.
Userspace applications can read this file to determine the
maximum number of Virtual Functions (VFs) a PCIe physical
function (PF) can support. Typically, this is the value reported
in the PF's SR-IOV extended capability structure's TotalVFs
element. Drivers have the ability at probe time to reduce the
value read from this file via the pci_sriov_set_totalvfs()
function.
What: /sys/bus/pci/devices/.../sriov_numvfs
Date: November 2012
Contact: Donald Dutile <ddutile@redhat.com>
Description:
This file appears when a physical PCIe device supports SR-IOV.
Userspace applications can read and write to this file to
determine and control the enablement or disablement of Virtual
Functions (VFs) on the physical function (PF). A read of this
file will return the number of VFs that are enabled on this PF.
A number written to this file will enable the specified
number of VFs. A userspace application would typically read the
file and check that the value is zero, and then write the number
of VFs that should be enabled on the PF; the value written
should be less than or equal to the value in the sriov_totalvfs
file. A userspace application wanting to disable the VFs would
write a zero to this file. The core ensures that valid values
are written to this file, and returns errors when values are not
valid. For example, writing a 2 to this file when sriov_numvfs
is not 0 and not 2 already will return an error. Writing a 10
when the value of sriov_totalvfs is 8 will return an error.