On 11/15/2016 12:15 PM, Jike Song wrote:
> On 11/14/2016 11:42 PM, Kirti Wankhede wrote:
>> Add a notifier calback to parent's ops structure of mdev device so that per
>> device notifer for vfio module is registered through vfio_mdev module.
>>
>> Signed-off-by: Kirti Wankhede <kwankhede@xxxxxxxxxx>
>> Signed-off-by: Neo Jia <cjia@xxxxxxxxxx>
>> Change-Id: Iafa6f1721aecdd6e50eb93b153b5621e6d29b637
>> ---
>> drivers/vfio/mdev/vfio_mdev.c | 19 +++++++++++++++++++
>> include/linux/mdev.h | 9 +++++++++
>> 2 files changed, 28 insertions(+)
>>
>> diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
>> index ffc36758cb84..1694b1635607 100644
>> --- a/drivers/vfio/mdev/vfio_mdev.c
>> +++ b/drivers/vfio/mdev/vfio_mdev.c
>> @@ -24,6 +24,15 @@
>> #define DRIVER_AUTHOR "NVIDIA Corporation"
>> #define DRIVER_DESC "VFIO based driver for Mediated device"
>>
>> +static int vfio_mdev_notifier(struct notifier_block *nb, unsigned long action,
>> + void *data)
>> +{
>> + struct mdev_device *mdev = container_of(nb, struct mdev_device, nb);
>> + struct parent_device *parent = mdev->parent;
>> +
>> + return parent->ops->notifier(mdev, action, data);
>> +}
>> +
>> static int vfio_mdev_open(void *device_data)
>> {
>> struct mdev_device *mdev = device_data;
>> @@ -40,6 +49,11 @@ static int vfio_mdev_open(void *device_data)
>> if (ret)
>> module_put(THIS_MODULE);
>>
>> + if (likely(parent->ops->notifier)) {
>> + mdev->nb.notifier_call = vfio_mdev_notifier;
>> + if (vfio_register_notifier(&mdev->dev, &mdev->nb))
>> + pr_err("Failed to register notifier for mdev\n");
>> + }
>
> Hi Kirti,
>
> Could you please move the notifier registration before parent->ops->open()?
> as you might know, I'm extending your vfio_register_notifier to also include
> the attaching/detaching events of vfio_group and kvm. Basically if vfio_group
> not attached to any kvm instance, the parent->ops->open() should return -ENODEV
> to indicate the failure, but to know whether kvm is available in open(), the
> notifier registration should be earlier.
>
Ok. That seem fine to me.
Thanks,
Kirti
> Of course I can call vfio_register_notifier() from an earlier place to
> workaround it, but it doesn't seem a canonical way.
>
> --
> Thanks,
> Jike
>
>> return ret;
>> }
>>
>> @@ -48,6 +62,11 @@ static void vfio_mdev_release(void *device_data)
>> struct mdev_device *mdev = device_data;
>> struct parent_device *parent = mdev->parent;
>>
>> + if (likely(parent->ops->notifier)) {
>> + if (vfio_unregister_notifier(&mdev->dev, &mdev->nb))
>> + pr_err("Failed to unregister notifier for mdev\n");
>> + }
>> +
>> if (likely(parent->ops->release))
>> parent->ops->release(mdev);
>>
>> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
>> index 4900cc472364..665afe0a4c31 100644
>> --- a/include/linux/mdev.h
>> +++ b/include/linux/mdev.h
>> @@ -37,6 +37,7 @@ struct mdev_device {
>> struct kref ref;
>> struct list_head next;
>> struct kobject *type_kobj;
>> + struct notifier_block nb;
>> };
>>
>> /**
>> @@ -85,6 +86,12 @@ struct mdev_device {
>> * @mmap: mmap callback
>> * @mdev: mediated device structure
>> * @vma: vma structure
>> + * @notifer: Notifier callback, currently only for
>> + * VFIO_IOMMU_NOTIFY_DMA_UNMAP action notified duing
>> + * DMA_UNMAP call on mapped iova range.
>> + * @mdev: mediated device structure
>> + * @action: Action for which notifier is called
>> + * @data: Data associated with the notifier
>> * Parent device that support mediated device should be registered with mdev
>> * module with parent_ops structure.
>> **/
>> @@ -106,6 +113,8 @@ struct parent_ops {
>> ssize_t (*ioctl)(struct mdev_device *mdev, unsigned int cmd,
>> unsigned long arg);
>> int (*mmap)(struct mdev_device *mdev, struct vm_area_struct *vma);
>> + int (*notifier)(struct mdev_device *mdev, unsigned long action,
>> + void *data);
>> };
>>
>> /* interface for exporting mdev supported type attributes */
>>
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