[RFC PATCH v2 3/9] vfio/pci: register/unregister vfio_pci_vendor_driver_ops

From: Yan Zhao
Date: Thu Jan 30 2020 - 21:20:35 EST


vfio_pci_vendor_driver_ops includes two parts:
(1) .probe() and .remove() interfaces to be called by vfio_pci_probe()
and vfio_pci_remove().
(2) pointer to struct vfio_device_ops. It will be registered as vfio
device ops if .probe() succeeds.

Suggested-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
Signed-off-by: Yan Zhao <yan.y.zhao@xxxxxxxxx>
---
drivers/vfio/pci/vfio_pci.c | 102 +++++++++++++++++++++++++++-
drivers/vfio/pci/vfio_pci_private.h | 6 ++
include/linux/vfio.h | 13 ++++
3 files changed, 120 insertions(+), 1 deletion(-)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index f72c6d80d0e9..1a08b7cc9246 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -62,6 +62,10 @@ static inline bool vfio_vga_disabled(void)
return true;
#endif
}
+static struct vfio_pci {
+ struct mutex vendor_drivers_lock;
+ struct list_head vendor_drivers_list;
+} vfio_pci;

/*
* Our VGA arbiter participation is limited since we don't know anything
@@ -1301,6 +1305,36 @@ static const struct vfio_device_ops vfio_pci_ops = {
static int vfio_pci_reflck_attach(struct vfio_pci_device *vdev);
static void vfio_pci_reflck_put(struct vfio_pci_reflck *reflck);

+static int probe_vendor_drivers(struct vfio_pci_device *vdev)
+{
+
+ struct vfio_pci_vendor_driver *driver;
+ int ret = -ENODEV;
+
+ request_module("vfio-pci:%x-%x", vdev->pdev->vendor,
+ vdev->pdev->device);
+
+ mutex_lock(&vfio_pci.vendor_drivers_lock);
+ list_for_each_entry(driver, &vfio_pci.vendor_drivers_list, next) {
+ void *data;
+
+ if (!try_module_get(driver->ops->owner))
+ continue;
+
+ data = driver->ops->probe(vdev->pdev);
+ if (IS_ERR(data)) {
+ module_put(driver->ops->owner);
+ continue;
+ }
+ vdev->vendor_driver = driver;
+ vdev->vendor_data = data;
+ ret = 0;
+ break;
+ }
+ mutex_unlock(&vfio_pci.vendor_drivers_lock);
+ return ret;
+}
+
static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
struct vfio_pci_device *vdev;
@@ -1346,7 +1380,11 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
mutex_init(&vdev->priv->ioeventfds_lock);
INIT_LIST_HEAD(&vdev->priv->ioeventfds_list);

- ret = vfio_add_group_dev(&pdev->dev, &vfio_pci_ops, vdev);
+ if (probe_vendor_drivers(vdev))
+ ret = vfio_add_group_dev(&pdev->dev, &vfio_pci_ops, vdev);
+ else
+ ret = vfio_add_group_dev(&pdev->dev,
+ vdev->vendor_driver->ops->device_ops, vdev);
if (ret) {
vfio_iommu_group_put(group, &pdev->dev);
kfree(vdev);
@@ -1383,6 +1421,7 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
vfio_pci_set_power_state(vdev, PCI_D3hot);
}

+
return ret;
}

@@ -1403,6 +1442,11 @@ static void vfio_pci_remove(struct pci_dev *pdev)
if (!disable_idle_d3)
vfio_pci_set_power_state(vdev, PCI_D0);

+ if (vdev->vendor_driver) {
+ vdev->vendor_driver->ops->remove(vdev->vendor_data);
+ module_put(vdev->vendor_driver->ops->owner);
+ }
+
kfree(vdev->priv->pm_save);
kfree(vdev);

@@ -1708,6 +1752,8 @@ static int __init vfio_pci_init(void)

vfio_pci_fill_ids();

+ mutex_init(&vfio_pci.vendor_drivers_lock);
+ INIT_LIST_HEAD(&vfio_pci.vendor_drivers_list);
return 0;

out_driver:
@@ -1715,6 +1761,60 @@ static int __init vfio_pci_init(void)
return ret;
}

+int __vfio_pci_register_vendor_driver(struct vfio_pci_vendor_driver_ops *ops)
+{
+ struct vfio_pci_vendor_driver *driver, *tmp;
+
+ if (!ops || !ops->device_ops)
+ return -EINVAL;
+
+ driver = kzalloc(sizeof(*driver), GFP_KERNEL);
+ if (!driver)
+ return -ENOMEM;
+
+ driver->ops = ops;
+
+ mutex_lock(&vfio_pci.vendor_drivers_lock);
+
+ /* Check for duplicates */
+ list_for_each_entry(tmp, &vfio_pci.vendor_drivers_list, next) {
+ if (tmp->ops->device_ops == ops->device_ops) {
+ mutex_unlock(&vfio_pci.vendor_drivers_lock);
+ kfree(driver);
+ return -EINVAL;
+ }
+ }
+
+ list_add(&driver->next, &vfio_pci.vendor_drivers_list);
+
+ mutex_unlock(&vfio_pci.vendor_drivers_lock);
+
+ if (!try_module_get(THIS_MODULE))
+ return -ENODEV;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(__vfio_pci_register_vendor_driver);
+
+void vfio_pci_unregister_vendor_driver(struct vfio_device_ops *device_ops)
+{
+ struct vfio_pci_vendor_driver *driver, *tmp;
+
+ mutex_lock(&vfio_pci.vendor_drivers_lock);
+ list_for_each_entry_safe(driver, tmp,
+ &vfio_pci.vendor_drivers_list, next) {
+ if (driver->ops->device_ops == device_ops) {
+ list_del(&driver->next);
+ mutex_unlock(&vfio_pci.vendor_drivers_lock);
+ kfree(driver);
+ module_put(THIS_MODULE);
+ return;
+ }
+ }
+ mutex_unlock(&vfio_pci.vendor_drivers_lock);
+}
+EXPORT_SYMBOL_GPL(vfio_pci_unregister_vendor_driver);
+
module_init(vfio_pci_init);
module_exit(vfio_pci_cleanup);

diff --git a/drivers/vfio/pci/vfio_pci_private.h b/drivers/vfio/pci/vfio_pci_private.h
index 4e0d1a38fe30..32013bb69ec4 100644
--- a/drivers/vfio/pci/vfio_pci_private.h
+++ b/drivers/vfio/pci/vfio_pci_private.h
@@ -84,6 +84,11 @@ struct vfio_pci_reflck {
struct mutex lock;
};

+struct vfio_pci_vendor_driver {
+ const struct vfio_pci_vendor_driver_ops *ops;
+ struct list_head next;
+};
+
struct vfio_pci_device_private {
void __iomem *barmap[PCI_STD_RESOURCE_END + 1];
bool bar_mmap_supported[PCI_STD_RESOURCE_END + 1];
@@ -119,6 +124,7 @@ struct vfio_pci_device_private {
struct list_head dummy_resources_list;
struct mutex ioeventfds_lock;
struct list_head ioeventfds_list;
+
};

#define is_intx(vdev) (vdev->irq_type == VFIO_PCI_INTX_IRQ_INDEX)
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 291e25b4d850..69519cf1fd4f 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -195,12 +195,25 @@ extern int vfio_virqfd_enable(void *opaque,
void *data, struct virqfd **pvirqfd, int fd);
extern void vfio_virqfd_disable(struct virqfd **pvirqfd);

+
+struct vfio_pci_vendor_driver_ops {
+ char *name;
+ struct module *owner;
+ void *(*probe)(struct pci_dev *pdev);
+ void (*remove)(void *vendor_data);
+ struct vfio_device_ops *device_ops;
+};
+int __vfio_pci_register_vendor_driver(struct vfio_pci_vendor_driver_ops *ops);
+void vfio_pci_unregister_vendor_driver(struct vfio_device_ops *device_ops);
+
struct vfio_pci_device_private;
struct vfio_pci_device {
struct pci_dev *pdev;
int num_regions;
int irq_type;
struct vfio_pci_device_private *priv;
+ struct vfio_pci_vendor_driver *vendor_driver;
+ void *vendor_data;
};

extern long vfio_pci_ioctl(void *device_data,
--
2.17.1