[PATCH 1/1] vfio-pci: Add SR-IOV VF configuration via sysfs

[Andre Richter <andre.o.richter@gmail.com>]

If a PCIe device bound to vfio-pci happens to be SR-IOV capabale,
there is no possibility to bring up/shutdown the device's VFs.

This patch adds a generic callback for the sysfs sriov_numvfs attribute.
The attribute will only show up for SR-IOV devices. Additionally,
each utilized pci_* function checks if the device is a PF.

Signed-off-by: Andre Richter <andre.o.richter@gmail.com>
---
 drivers/vfio/pci/vfio_pci.c | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index f782533..2f6dfb3 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -919,12 +919,27 @@ static struct pci_error_handlers vfio_err_handlers = {
 	.error_detected = vfio_pci_aer_err_detected,
 };
 
+static int vfio_pci_sriov_configure(struct pci_dev *pdev, int num_vfs)
+{
+	int ret = 0;
+
+	if (num_vfs > 0) {
+		ret = pci_enable_sriov(pdev, num_vfs);
+		if (!ret)
+			ret = pci_num_vf(pdev);
+	} else
+		pci_disable_sriov(pdev);
+
+	return ret;
+}
+
 static struct pci_driver vfio_pci_driver = {
-	.name		= "vfio-pci",
-	.id_table	= NULL, /* only dynamic ids */
-	.probe		= vfio_pci_probe,
-	.remove		= vfio_pci_remove,
-	.err_handler	= &vfio_err_handlers,
+	.name			= "vfio-pci",
+	.id_table		= NULL, /* only dynamic ids */
+	.probe			= vfio_pci_probe,
+	.remove			= vfio_pci_remove,
+	.sriov_configure	= vfio_pci_sriov_configure,
+	.err_handler		= &vfio_err_handlers,
 };
 
 /*
-- 
1.9.1