On Thu, 17 Oct 2019 17:07:55 +0200 Cornelia Huck cohuck@redhat.com wrote:
On Thu, 17 Oct 2019 18:48:33 +0800 Jason Wang jasowang@redhat.com wrote:
Currently, except for the create and remove, the rest of mdev_parent_ops is designed for vfio-mdev driver only and may not help for kernel mdev driver. With the help of class id, this patch introduces device specific callbacks inside mdev_device structure. This allows different set of callback to be used by vfio-mdev and virtio-mdev.
Signed-off-by: Jason Wang jasowang@redhat.com
.../driver-api/vfio-mediated-device.rst | 25 +++++---- MAINTAINERS | 1 + drivers/gpu/drm/i915/gvt/kvmgt.c | 18 ++++--- drivers/s390/cio/vfio_ccw_ops.c | 18 ++++--- drivers/s390/crypto/vfio_ap_ops.c | 14 +++-- drivers/vfio/mdev/mdev_core.c | 18 +++++-- drivers/vfio/mdev/mdev_private.h | 1 + drivers/vfio/mdev/vfio_mdev.c | 37 ++++++------- include/linux/mdev.h | 45 ++++------------ include/linux/vfio_mdev.h | 52 +++++++++++++++++++ samples/vfio-mdev/mbochs.c | 20 ++++--- samples/vfio-mdev/mdpy.c | 20 ++++--- samples/vfio-mdev/mtty.c | 18 ++++--- 13 files changed, 184 insertions(+), 103 deletions(-) create mode 100644 include/linux/vfio_mdev.h
diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst index f9a78d75a67a..0cca84d19603 100644 --- a/Documentation/driver-api/vfio-mediated-device.rst +++ b/Documentation/driver-api/vfio-mediated-device.rst @@ -152,11 +152,22 @@ callbacks per mdev parent device, per mdev type, or any other categorization. Vendor drivers are expected to be fully asynchronous in this respect or provide their own internal resource protection.)
-The callbacks in the mdev_parent_ops structure are as follows:
-* open: open callback of mediated device -* close: close callback of mediated device -* ioctl: ioctl callback of mediated device +As multiple types of mediated devices may be supported, the device +must set up the class id and the device specific callbacks in create()
s/in create()/in the create()/
+callback. E.g for vfio-mdev device it needs to be done through:
"Each class provides a helper function to do so; e.g. for vfio-mdev devices, the function to be called is:"
?
- int mdev_set_vfio_ops(struct mdev_device *mdev,
const struct vfio_mdev_ops *vfio_ops);+The class id (set to MDEV_CLASS_ID_VFIO) is used to match a device
"(set by this helper function to MDEV_CLASS_ID_VFIO)" ?
+with an mdev driver via its id table. The device specific callbacks +(specified in *ops) are obtainable via mdev_get_dev_ops() (for use by
"(specified in *vfio_ops by the caller)" ?
+the mdev bus driver). A vfio-mdev device (class id MDEV_CLASS_ID_VFIO) +uses the following device-specific ops:
+* open: open callback of vfio mediated device +* close: close callback of vfio mediated device +* ioctl: ioctl callback of vfio mediated device
- read : read emulation callback
- write: write emulation callback
- mmap: mmap emulation callback
@@ -167,10 +178,6 @@ register itself with the mdev core driver:: extern int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops);
-It is also required to specify the class_id in create() callback through::
- int mdev_set_class(struct mdev_device *mdev, u16 id);
I'm wondering if this patch set should start out with introducing helper functions already (i.e. don't introduce mdev_set_class(), but start out with mdev_set_class_vfio() which will gain the *vfio_ops argument in this patch.)
Yes, it would be cleaner, but is it really worth the churn? Correct me if I'm wrong, but I think we get to the same point after this patch and aside from the function name itself, the difference is really just that the class_id is briefly exposed to the parent driver, right? Thanks,
Alex
However, the mdev_parent_ops structure is not required in the function call that a driver should use to unregister itself with the mdev core driver::
(...)
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c index 3a9c52d71b4e..d0f3113c8071 100644 --- a/drivers/vfio/mdev/mdev_core.c +++ b/drivers/vfio/mdev/mdev_core.c @@ -45,15 +45,23 @@ void mdev_set_drvdata(struct mdev_device *mdev, void *data) } EXPORT_SYMBOL(mdev_set_drvdata);
-/* Specify the class for the mdev device, this must be called during
- create() callback.
+/* Specify the VFIO device ops for the mdev device, this
*/
- must be called during create() callback for VFIO mdev device.
/*
- Specify the mdev device to be a VFIO mdev device, and set the
- VFIO devices ops for it. This must be called from the create()
- callback for VFIO mdev devices.
*/
?
-void mdev_set_class(struct mdev_device *mdev, u16 id) +void mdev_set_vfio_ops(struct mdev_device *mdev,
const struct vfio_mdev_device_ops *vfio_ops){ WARN_ON(mdev->class_id);
- mdev->class_id = id;
- mdev->class_id = MDEV_CLASS_ID_VFIO;
- mdev->device_ops = vfio_ops;
} -EXPORT_SYMBOL(mdev_set_class); +EXPORT_SYMBOL(mdev_set_vfio_ops);
+const void *mdev_get_dev_ops(struct mdev_device *mdev) +{
- return mdev->device_ops;
+} +EXPORT_SYMBOL(mdev_get_dev_ops);
struct device *mdev_dev(struct mdev_device *mdev) {
(...)
The code change looks good to me; I'm just wondering if we should introduce mdev_set_class() at all (see above).