virtio_pci: support enabling VFs

There is a new feature bit allocated in virtio spec to
support SR-IOV (Single Root I/O Virtualization):

https://github.com/oasis-tcs/virtio-spec/issues/11

This patch enables the support for this feature bit in
virtio driver.

Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
index 48d4d1c..1d4467b 100644 (file)
--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -577,6 +577,8 @@ static void virtio_pci_remove(struct pci_dev *pci_dev)
        struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
        struct device *dev = get_device(&vp_dev->vdev.dev);
 
+       pci_disable_sriov(pci_dev);
+
        unregister_virtio_device(&vp_dev->vdev);
 
        if (vp_dev->ioaddr)
@@ -588,6 +590,33 @@ static void virtio_pci_remove(struct pci_dev *pci_dev)
        put_device(dev);
 }
 
+static int virtio_pci_sriov_configure(struct pci_dev *pci_dev, int num_vfs)
+{
+       struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
+       struct virtio_device *vdev = &vp_dev->vdev;
+       int ret;
+
+       if (!(vdev->config->get_status(vdev) & VIRTIO_CONFIG_S_DRIVER_OK))
+               return -EBUSY;
+
+       if (!__virtio_test_bit(vdev, VIRTIO_F_SR_IOV))
+               return -EINVAL;
+
+       if (pci_vfs_assigned(pci_dev))
+               return -EPERM;
+
+       if (num_vfs == 0) {
+               pci_disable_sriov(pci_dev);
+               return 0;
+       }
+
+       ret = pci_enable_sriov(pci_dev, num_vfs);
+       if (ret < 0)
+               return ret;
+
+       return num_vfs;
+}
+
 static struct pci_driver virtio_pci_driver = {
        .name           = "virtio-pci",
        .id_table       = virtio_pci_id_table,
@@ -596,6 +625,7 @@ static struct pci_driver virtio_pci_driver = {
 #ifdef CONFIG_PM_SLEEP
        .driver.pm      = &virtio_pci_pm_ops,
 #endif
+       .sriov_configure = virtio_pci_sriov_configure,
 };
 
 module_pci_driver(virtio_pci_driver);

diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index 2555d80..07571da 100644 (file)
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -153,14 +153,28 @@ static u64 vp_get_features(struct virtio_device *vdev)
        return features;
 }
 
+static void vp_transport_features(struct virtio_device *vdev, u64 features)
+{
+       struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+       struct pci_dev *pci_dev = vp_dev->pci_dev;
+
+       if ((features & BIT_ULL(VIRTIO_F_SR_IOV)) &&
+                       pci_find_ext_capability(pci_dev, PCI_EXT_CAP_ID_SRIOV))
+               __virtio_set_bit(vdev, VIRTIO_F_SR_IOV);
+}
+
 /* virtio config->finalize_features() implementation */
 static int vp_finalize_features(struct virtio_device *vdev)
 {
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+       u64 features = vdev->features;
 
        /* Give virtio_ring a chance to accept features. */
        vring_transport_features(vdev);
 
+       /* Give virtio_pci a chance to accept features. */
+       vp_transport_features(vdev, features);
+
        if (!__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
                dev_err(&vdev->dev, "virtio: device uses modern interface "
                        "but does not have VIRTIO_F_VERSION_1\n");

diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h
index 308e209..b7c1f4e 100644 (file)
--- a/include/uapi/linux/virtio_config.h
+++ b/include/uapi/linux/virtio_config.h
@@ -49,7 +49,7 @@
  * transport being used (eg. virtio_ring), the rest are per-device feature
  * bits. */
 #define VIRTIO_TRANSPORT_F_START       28
-#define VIRTIO_TRANSPORT_F_END         34
+#define VIRTIO_TRANSPORT_F_END         38
 
 #ifndef VIRTIO_CONFIG_NO_LEGACY
 /* Do we get callbacks when the ring is completely used, even if we've
@@ -71,4 +71,9 @@
  * this is for compatibility with legacy systems.
  */
 #define VIRTIO_F_IOMMU_PLATFORM                33
+
+/*
+ * Does the device support Single Root I/O Virtualization?
+ */
+#define VIRTIO_F_SR_IOV                        37
 #endif /* _UAPI_LINUX_VIRTIO_CONFIG_H */