Messages in this thread | | | Subject | Re: [PATCH V4 3/6] mdev: introduce device specific ops | From | Jason Wang <> | Date | Fri, 18 Oct 2019 15:34:44 +0800 |
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On 2019/10/17 下午11:07, Cornelia Huck 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()/
Will fix.
> >> +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:" > > ?
This looks better.
> >> + >> + 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)" ?
Yes.
>> +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)" ?
Yes.
>> +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.)
I think it doesn't harm to keep it as is since in patch 1 we introduce class_id and bus match method based on that without device ops there. But if you stick I can change.
Thanks
> >> 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).
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