diff options
| author | Bodong Wang <bodong@mellanox.com> | 2017-04-13 01:51:40 +0300 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2017-04-20 08:53:51 -0500 |
| commit | 0e7df22401a3dfd403b26dea62dd00e0598b538b (patch) | |
| tree | 484063ef8f232bf8d51d998a1331513a9f2c8b5a /Documentation | |
| parent | f65fd1aa4f9881d5540192d11f7b8ed2fec936db (diff) | |
PCI: Add sysfs sriov_drivers_autoprobe to control VF driver binding
Sometimes it is not desirable to bind SR-IOV VFs to drivers. This can save
host side resource usage by VF instances that will be assigned to VMs.
Add a new PCI sysfs interface "sriov_drivers_autoprobe" to control that
from the PF. To modify it, echo 0/n/N (disable probe) or 1/y/Y (enable
probe) to:
/sys/bus/pci/devices/<DOMAIN:BUS:DEVICE.FUNCTION>/sriov_drivers_autoprobe
Note that this must be done before enabling VFs. The change will not take
effect if VFs are already enabled. Simply, one can disable VFs by setting
sriov_numvfs to 0, choose whether to probe or not, and then re-enable the
VFs by restoring sriov_numvfs.
[bhelgaas: changelog, ABI doc]
Signed-off-by: Bodong Wang <bodong@mellanox.com>
Signed-off-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-pci | 22 | ||||
| -rw-r--r-- | Documentation/PCI/pci-iov-howto.txt | 12 |
2 files changed, 34 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci index 5a1732b78707..b728f700340d 100644 --- a/Documentation/ABI/testing/sysfs-bus-pci +++ b/Documentation/ABI/testing/sysfs-bus-pci @@ -301,3 +301,25 @@ Contact: Emil Velikov <emil.l.velikov@gmail.com> Description: This file contains the revision field of the the PCI device. The value comes from device config space. The file is read only. + +What: /sys/bus/pci/devices/.../sriov_drivers_autoprobe +Date: April 2017 +Contact: Bodong Wang<bodong@mellanox.com> +Description: + This file is associated with the PF of a device that + supports SR-IOV. It determines whether newly-enabled VFs + are immediately bound to a driver. It initially contains + 1, which means the kernel automatically binds VFs to a + compatible driver immediately after they are enabled. If + an application writes 0 to the file before enabling VFs, + the kernel will not bind VFs to a driver. + + A typical use case is to write 0 to this file, then enable + VFs, then assign the newly-created VFs to virtual machines. + Note that changing this file does not affect already- + enabled VFs. In this scenario, the user must first disable + the VFs, write 0 to sriov_drivers_autoprobe, then re-enable + the VFs. + + This is similar to /sys/bus/pci/drivers_autoprobe, but + affects only the VFs associated with a specific PF. diff --git a/Documentation/PCI/pci-iov-howto.txt b/Documentation/PCI/pci-iov-howto.txt index 2d91ae251982..d2a84151e99c 100644 --- a/Documentation/PCI/pci-iov-howto.txt +++ b/Documentation/PCI/pci-iov-howto.txt @@ -68,6 +68,18 @@ To disable SR-IOV capability: echo 0 > \ /sys/bus/pci/devices/<DOMAIN:BUS:DEVICE.FUNCTION>/sriov_numvfs +To enable auto probing VFs by a compatible driver on the host, run +command below before enabling SR-IOV capabilities. This is the +default behavior. + echo 1 > \ + /sys/bus/pci/devices/<DOMAIN:BUS:DEVICE.FUNCTION>/sriov_drivers_autoprobe + +To disable auto probing VFs by a compatible driver on the host, run +command below before enabling SR-IOV capabilities. Updating this +entry will not affect VFs which are already probed. + echo 0 > \ + /sys/bus/pci/devices/<DOMAIN:BUS:DEVICE.FUNCTION>/sriov_drivers_autoprobe + 3.2 Usage example Following piece of code illustrates the usage of the SR-IOV API. |