On Tue, Nov 27, 2012 at 8:31 PM, Donald Dutile <ddutile@xxxxxxxxxx> wrote:
> Signed-off: Donald Dutile <ddutile@xxxxxxxxxx>
>
Thanks, Don. I added this to my -next branch, for merging in the v3.8
merge window.
I removed the trailing underscore from sriov_numvfs_.
> Documentation/ABI/testing/sysfs-bus-pci | 34 +++++++++++++++++++++++
> Documentation/PCI/pci-iov-howto.txt | 48 ++++++++++++++++++++++++++++++---
> 2 files changed, 78 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
> index dff1f48..1cb389d 100644
> --- a/Documentation/ABI/testing/sysfs-bus-pci
> +++ b/Documentation/ABI/testing/sysfs-bus-pci
> @@ -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@xxxxxxxxxx>
> +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@xxxxxxxxxx>
> +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.
> diff --git a/Documentation/PCI/pci-iov-howto.txt b/Documentation/PCI/pci-iov-howto.txt
> index fc73ef5..c41cf95 100644
> --- a/Documentation/PCI/pci-iov-howto.txt
> +++ b/Documentation/PCI/pci-iov-howto.txt
> @@ -2,6 +2,9 @@
> Copyright (C) 2009 Intel Corporation
> Yu Zhao <yu.zhao@xxxxxxxxx>
>
> + Update: November 2012
> + -- sysfs-based SRIOV enable-/disable-ment
> + Donald Dutile <ddutile@xxxxxxxxxx>
>
> 1. Overview
>
> @@ -24,10 +27,21 @@ real existing PCI device.
>
> 2.1 How can I enable SR-IOV capability
>
> -The device driver (PF driver) will control the enabling and disabling
> -of the capability via API provided by SR-IOV core. If the hardware
> -has SR-IOV capability, loading its PF driver would enable it and all
> -VFs associated with the PF.
> +Multiple methods are available for SR-IOV enablement.
> +In the first method, the device driver (PF driver) will control the
> +enabling and disabling of the capability via API provided by SR-IOV core.
> +If the hardware has SR-IOV capability, loading its PF driver would
> +enable it and all VFs associated with the PF. Some PF drivers require
> +a module parameter to be set to determine the number of VFs to enable.
> +In the second method, a write to the sysfs file sriov_numvfs will
> +enable and disable the VFs associated with a PCIe PF. This method
> +enables per-PF, VF enable/disable values versus the first method,
> +which applies to all PFs of the same device. Additionally, the
> +PCI SRIOV core support ensures that enable/disable operations are
> +valid to reduce duplication in multiple drivers for the same
> +checks, e.g., check numvfs == 0 if enabling VFs, ensure
> +numvfs <= totalvfs.
> +The second method is the recommended method for new/future VF devices.
>
> 2.2 How can I use the Virtual Functions
>
> @@ -40,13 +54,22 @@ requires device driver that is same as a normal PCI device's.
> 3.1 SR-IOV API
>
> To enable SR-IOV capability:
> +(a) For the first method, in the driver:
> int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn);
> 'nr_virtfn' is number of VFs to be enabled.
> +(b) For the second method, from sysfs:
> + echo 'nr_virtfn' > \
> + /sys/bus/pci/devices/<DOMAIN:BUS:DEVICE.FUNCTION>/sriov_numvfs
>
> To disable SR-IOV capability:
> +(a) For the first method, in the driver:
> void pci_disable_sriov(struct pci_dev *dev);
> +(b) For the second method, from sysfs:
> + echo 0 > \
> + /sys/bus/pci/devices/<DOMAIN:BUS:DEVICE.FUNCTION>/sriov_numvfs
>
> To notify SR-IOV core of Virtual Function Migration:
> +(a) In the driver:
> irqreturn_t pci_sriov_migration(struct pci_dev *dev);
>
> 3.2 Usage example
> @@ -88,6 +111,22 @@ static void dev_shutdown(struct pci_dev *dev)
> ...
> }
>
> +static int dev_sriov_configure(struct pci_dev *dev, int numvfs)
> +{
> + if (numvfs > 0) {
> + ...
> + pci_enable_sriov(dev, numvfs);
> + ...
> + return numvfs;
> + }
> + if (numvfs == 0) {
> + ....
> + pci_disable_sriov(dev);
> + ...
> + return 0;
> + }
> +}
> +
> static struct pci_driver dev_driver = {
> .name = "SR-IOV Physical Function driver",
> .id_table = dev_id_table,
> @@ -96,4 +135,5 @@ static struct pci_driver dev_driver = {
> .suspend = dev_suspend,
> .resume = dev_resume,
> .shutdown = dev_shutdown,
> + .sriov_configure = dev_sriov_configure,
> };
> --
> 1.7.10.2.552.gaa3bb87
>
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