Loading Documentation/ABI/testing/sysfs-bus-pci +34 −0 Original line number Diff line number Diff line Loading @@ -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. Documentation/PCI/pci-iov-howto.txt +44 −4 Original line number Diff line number Diff line Loading @@ -2,6 +2,9 @@ Copyright (C) 2009 Intel Corporation Yu Zhao <yu.zhao@intel.com> Update: November 2012 -- sysfs-based SRIOV enable-/disable-ment Donald Dutile <ddutile@redhat.com> 1. Overview Loading @@ -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 Loading @@ -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 Loading Loading @@ -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, Loading @@ -96,4 +135,5 @@ static struct pci_driver dev_driver = { .suspend = dev_suspend, .resume = dev_resume, .shutdown = dev_shutdown, .sriov_configure = dev_sriov_configure, }; Loading
Documentation/ABI/testing/sysfs-bus-pci +34 −0 Original line number Diff line number Diff line Loading @@ -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.
Documentation/PCI/pci-iov-howto.txt +44 −4 Original line number Diff line number Diff line Loading @@ -2,6 +2,9 @@ Copyright (C) 2009 Intel Corporation Yu Zhao <yu.zhao@intel.com> Update: November 2012 -- sysfs-based SRIOV enable-/disable-ment Donald Dutile <ddutile@redhat.com> 1. Overview Loading @@ -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 Loading @@ -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 Loading Loading @@ -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, Loading @@ -96,4 +135,5 @@ static struct pci_driver dev_driver = { .suspend = dev_suspend, .resume = dev_resume, .shutdown = dev_shutdown, .sriov_configure = dev_sriov_configure, };
