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authorAlexander Duyck <alexander.h.duyck@intel.com>2018-04-21 15:23:09 -0500
committerBjorn Helgaas <bhelgaas@google.com>2018-04-24 16:46:56 -0500
commit8effc395c2097e258fcedfc02ed4a66d45fb4238 (patch)
treec0b573e7630e44c68c2bbe9f816135bf52363459 /drivers/pci/iov.c
parent60cc43fc888428bb2f18f08997432d426a243338 (diff)
downloadlwn-8effc395c2097e258fcedfc02ed4a66d45fb4238.tar.gz
lwn-8effc395c2097e258fcedfc02ed4a66d45fb4238.zip
PCI/IOV: Add pci_sriov_configure_simple()
SR-IOV (Single Root I/O Virtualization) is an optional PCIe capability (see PCIe r4.0, sec 9). A PCIe Function with the SR-IOV capability is referred to as a PF (Physical Function). If SR-IOV is enabled on the PF, several VFs (Virtual Functions) may be created. The VFs can be individually assigned to virtual machines, which allows them to share a single hardware device while being isolated from each other. Some SR-IOV devices have resources such as queues and interrupts that must be set up in the PF before enabling the VFs, so they require a PF driver to do that. Other SR-IOV devices don't require any PF setup before enabling VFs. Add a pci_sriov_configure_simple() interface so PF drivers for such devices can use it without repeating the VF-enabling code. Tested-by: Mark Rustad <mark.d.rustad@intel.com> Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com> [bhelgaas: changelog, comment] Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Greg Rose <gvrose8192@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de>:wq
Diffstat (limited to 'drivers/pci/iov.c')
-rw-r--r--drivers/pci/iov.c36
1 files changed, 36 insertions, 0 deletions
diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 8adf4a64f291..192b82898a38 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -833,3 +833,39 @@ int pci_sriov_get_totalvfs(struct pci_dev *dev)
return dev->sriov->total_VFs;
}
EXPORT_SYMBOL_GPL(pci_sriov_get_totalvfs);
+
+/**
+ * pci_sriov_configure_simple - helper to configure SR-IOV
+ * @dev: the PCI device
+ * @nr_virtfn: number of virtual functions to enable, 0 to disable
+ *
+ * Enable or disable SR-IOV for devices that don't require any PF setup
+ * before enabling SR-IOV. Return value is negative on error, or number of
+ * VFs allocated on success.
+ */
+int pci_sriov_configure_simple(struct pci_dev *dev, int nr_virtfn)
+{
+ int rc;
+
+ might_sleep();
+
+ if (!dev->is_physfn)
+ return -ENODEV;
+
+ if (pci_vfs_assigned(dev)) {
+ pci_warn(dev, "Cannot modify SR-IOV while VFs are assigned\n");
+ return -EPERM;
+ }
+
+ if (nr_virtfn == 0) {
+ sriov_disable(dev);
+ return 0;
+ }
+
+ rc = sriov_enable(dev, nr_virtfn);
+ if (rc < 0)
+ return rc;
+
+ return nr_virtfn;
+}
+EXPORT_SYMBOL_GPL(pci_sriov_configure_simple);