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

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 8adf4a64f2919ad5f50f13365564b6d11917f08f..192b82898a38426d8bafc68ecfe5d7ad08987c2b 100644 (file)
--- 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);

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 73178a2fcee09b10b0e5a78a838213d9fe204b65..911f9098a466b74b0b4b345d46be217d8fdb9e0a 100644 (file)
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1954,6 +1954,7 @@ int pci_num_vf(struct pci_dev *dev);
 int pci_vfs_assigned(struct pci_dev *dev);
 int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs);
 int pci_sriov_get_totalvfs(struct pci_dev *dev);
+int pci_sriov_configure_simple(struct pci_dev *dev, int nr_virtfn);
 resource_size_t pci_iov_resource_size(struct pci_dev *dev, int resno);
 void pci_vf_drivers_autoprobe(struct pci_dev *dev, bool probe);
 
@@ -1986,6 +1987,7 @@ static inline int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs)
 { return 0; }
 static inline int pci_sriov_get_totalvfs(struct pci_dev *dev)
 { return 0; }
+#define pci_sriov_configure_simple     NULL
 static inline resource_size_t pci_iov_resource_size(struct pci_dev *dev, int resno)
 { return 0; }
 static inline void pci_vf_drivers_autoprobe(struct pci_dev *dev, bool probe) { }