[V3,2/3] vfio/pci: Allow control SR-IOV through sysfs interface

Commit Message

Ilya Lesokhin Aug. 18, 2016, 7:29 a.m. UTC

This patch allows enabling and disabling SR-IOV for
devices probed by vfio-pci.
Since the devices might be assigned to an untrusted entities
we use driver_override to make sure the VFs are also
probed by the the vfio-pci driver.

Signed-off-by: Ilya Lesokhin <[e-mail]>
---
 drivers/vfio/pci/vfio_pci.c | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

Comments

Christoph Hellwig Aug. 18, 2016, 10:11 p.m. UTC | #1

On Thu, Aug 18, 2016 at 10:29:16AM +0300, Ilya Lesokhin wrote:
> +static int vfio_pci_sriov_configure(struct pci_dev *pdev, int num_vfs)
> +{
> +	if (!num_vfs) {
> +		pci_disable_sriov(pdev);
> +		return 0;
> +	}
> +
> +	return pci_enable_sriov_with_override(pdev,
> +					      num_vfs,
> +					     "vfio-pci");
> +}

I have to admit that I don't really like this API.  Would it be
major burden for use case to just have a flag instead that disables
automatic driver attachments for VFs and requires manual binding
instead?
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Patch

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index d624a52..6a203a7 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -297,6 +297,7 @@  static void vfio_pci_disable(struct vfio_pci_device *vdev)
 	struct vfio_pci_dummy_resource *dummy_res, *tmp;
 	int i, bar;
 
+	pci_disable_sriov(pdev);
 	/* Stop the device from further DMA */
 	pci_clear_master(pdev);
 
@@ -1314,12 +1315,25 @@  static const 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)
+{
+	if (!num_vfs) {
+		pci_disable_sriov(pdev);
+		return 0;
+	}
+
+	return pci_enable_sriov_with_override(pdev,
+					      num_vfs,
+					     "vfio-pci");
+}
+
 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,
+	.err_handler	 = &vfio_err_handlers,
+	.sriov_configure = vfio_pci_sriov_configure,
 };
 
 struct vfio_devices {