From: Liang-Min Wang <liang-min.w...@intel.com>

When a SR-IOV capable device is bound with vfio-pci, the
device loses capability of creating SR-IOV instances through /sy/bus/
pci/devices/.../sriov_numvfs. This patch re-activates this capability
for a PCIe device that is SR-IOV capable and is bound with vfio-pci.ko.
This patch also disables drivers_autoprobe attribute of SR-IOV devices
created from vfio-pci bound device by default, so user-space PF device
can coordinate the bring-up of SR-IOV devices

Signed-off-by: Liang-Min Wang <liang-min.w...@intel.com>
---
 drivers/pci/pci-driver.c    | 12 ++++++++++++
 drivers/vfio/pci/vfio_pci.c | 22 ++++++++++++++++++++++
 include/linux/pci.h         |  1 +
 3 files changed, 35 insertions(+)

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 7f47bb7..19522fe 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -1467,6 +1467,18 @@ void pci_dev_put(struct pci_dev *dev)
 }
 EXPORT_SYMBOL(pci_dev_put);
 
+/**
+ * pci_dev_sriov_autoprobe_set - set device sriov driver autoprobe
+ * @dev: device with which sriov autoprobe will be set
+ *
+ */
+void pci_dev_sriov_autoprobe_set(struct pci_dev *dev, bool autoprobe)
+{
+       if (dev && dev->sriov)
+               dev->sriov->drivers_autoprobe = autoprobe;
+}
+EXPORT_SYMBOL(pci_dev_sriov_autoprobe_set);
+
 static int pci_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
        struct pci_dev *pdev;
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index f041b1a..004836c 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -1213,6 +1213,8 @@ static int vfio_pci_probe(struct pci_dev *pdev, const 
struct pci_device_id *id)
                return -ENOMEM;
        }
 
+       /* disable sriov automatic driver attachment */
+       pci_dev_sriov_autoprobe_set(pdev, false);
        vdev->pdev = pdev;
        vdev->irq_type = VFIO_PCI_NUM_IRQS;
        mutex_init(&vdev->igate);
@@ -1256,6 +1258,7 @@ static void vfio_pci_remove(struct pci_dev *pdev)
        if (!vdev)
                return;
 
+       pci_disable_sriov(pdev);
        vfio_iommu_group_put(pdev->dev.iommu_group, &pdev->dev);
        kfree(vdev->region);
        kfree(vdev);
@@ -1303,12 +1306,31 @@ static pci_ers_result_t 
vfio_pci_aer_err_detected(struct pci_dev *pdev,
        .error_detected = vfio_pci_aer_err_detected,
 };
 
+static int vfio_sriov_configure(struct pci_dev *pdev, int num_vfs)
+{
+       int status;
+
+       if (!num_vfs) {
+               pci_disable_sriov(pdev);
+               return 0;
+       }
+
+       status = pci_enable_sriov(pdev, num_vfs);
+       if (!status) {
+               pr_crit("Created %d SR-IOV from a user-space driver based upon 
vfio-pci\n", num_vfs);
+               add_taint(TAINT_USER, LOCKDEP_STILL_OK);
+       }
+
+       return status;
+}
+
 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,
+       .sriov_configure = vfio_sriov_configure,
 };
 
 struct vfio_devices {
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 0403894..e04b69d 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -921,6 +921,7 @@ struct resource *pci_find_parent_resource(const struct 
pci_dev *dev,
 struct pci_dev *pci_dev_get(struct pci_dev *dev);
 void pci_dev_put(struct pci_dev *dev);
 void pci_remove_bus(struct pci_bus *b);
+void pci_dev_sriov_autoprobe_set(struct pci_dev *dev, bool autoprobe);
 void pci_stop_and_remove_bus_device(struct pci_dev *dev);
 void pci_stop_and_remove_bus_device_locked(struct pci_dev *dev);
 void pci_stop_root_bus(struct pci_bus *bus);
-- 
1.9.1

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