diff mbox

[v13,12/22] vfio: Add notifier callback to parent's ops structure of mdev

Message ID 1479223805-22895-13-git-send-email-kwankhede@nvidia.com
State New
Headers show

Commit Message

Kirti Wankhede Nov. 15, 2016, 3:29 p.m. UTC 
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@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
Change-Id: Iafa6f1721aecdd6e50eb93b153b5621e6d29b637
---
 drivers/vfio/mdev/vfio_mdev.c | 25 ++++++++++++++++++++++++-
 include/linux/mdev.h          |  9 +++++++++
 2 files changed, 33 insertions(+), 1 deletion(-)

Comments

Dong Jia Shi Nov. 16, 2016, 6:37 a.m. UTC | #1 
* Kirti Wankhede <kwankhede@nvidia.com> [2016-11-15 20:59:55 +0530]:

Hi Kirti,

[...]

> diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
> index ffc36758cb84..4fc63db38829 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;
> @@ -36,9 +45,18 @@ static int vfio_mdev_open(void *device_data)
>  	if (!try_module_get(THIS_MODULE))
>  		return -ENODEV;
> 
> +	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");
I think we should just return here if the error value is not -ENOTTY.

> +	}
> +
>  	ret = parent->ops->open(mdev);
> -	if (ret)
> +	if (ret) {
> +		if (likely(parent->ops->notifier))
> +			vfio_unregister_notifier(&mdev->dev, &mdev->nb);
>  		module_put(THIS_MODULE);
> +	}
> 
>  	return ret;
>  }
[...]
Kirti Wankhede Nov. 16, 2016, 3:17 p.m. UTC | #2 
On 11/16/2016 12:07 PM, Dong Jia Shi wrote:
> * Kirti Wankhede <kwankhede@nvidia.com> [2016-11-15 20:59:55 +0530]:
> 
> Hi Kirti,
> 
> [...]
> 
>> diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
>> index ffc36758cb84..4fc63db38829 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;
>> @@ -36,9 +45,18 @@ static int vfio_mdev_open(void *device_data)
>>  	if (!try_module_get(THIS_MODULE))
>>  		return -ENODEV;
>>
>> +	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");
> I think we should just return here if the error value is not -ENOTTY.
> 

It might be the case where iommu backend module might not support
.register_notifier(). In that case vfio_register_notifier() returns
-ENOTTY and that should not fail this open() call
Changing it to:

        ret = vfio_register_notifier(&mdev->dev, &mdev->nb);
        if (ret && (ret != -ENOTTY)) {
                pr_err("Failed to register notifier for mdev\n");
                module_put(THIS_MODULE);
                return ret;
        }

Thanks,
Kirti
Dong Jia Shi Nov. 17, 2016, 1:32 a.m. UTC | #3 
* Kirti Wankhede <kwankhede@nvidia.com> [2016-11-16 20:47:18 +0530]:

> 
> 
> On 11/16/2016 12:07 PM, Dong Jia Shi wrote:
> > * Kirti Wankhede <kwankhede@nvidia.com> [2016-11-15 20:59:55 +0530]:
> > 
> > Hi Kirti,
> > 
> > [...]
> > 
> >> diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
> >> index ffc36758cb84..4fc63db38829 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;
> >> @@ -36,9 +45,18 @@ static int vfio_mdev_open(void *device_data)
> >>  	if (!try_module_get(THIS_MODULE))
> >>  		return -ENODEV;
> >>
> >> +	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");
> > I think we should just return here if the error value is not -ENOTTY.
> > 
> 
> It might be the case where iommu backend module might not support
> .register_notifier(). In that case vfio_register_notifier() returns
> -ENOTTY and that should not fail this open() call
> Changing it to:
> 
>         ret = vfio_register_notifier(&mdev->dev, &mdev->nb);
>         if (ret && (ret != -ENOTTY)) {
>                 pr_err("Failed to register notifier for mdev\n");
>                 module_put(THIS_MODULE);
>                 return ret;
>         }
Nod. And we need not call vfio_unregister_notifier once error occurs in
open() in this case.

> 
> Thanks,
> Kirti
>
diff mbox

Patch

diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
index ffc36758cb84..4fc63db38829 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;
@@ -36,9 +45,18 @@  static int vfio_mdev_open(void *device_data)
 	if (!try_module_get(THIS_MODULE))
 		return -ENODEV;
 
+	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");
+	}
+
 	ret = parent->ops->open(mdev);
-	if (ret)
+	if (ret) {
+		if (likely(parent->ops->notifier))
+			vfio_unregister_notifier(&mdev->dev, &mdev->nb);
 		module_put(THIS_MODULE);
+	}
 
 	return ret;
 }
@@ -51,6 +69,11 @@  static void vfio_mdev_release(void *device_data)
 	if (likely(parent->ops->release))
 		parent->ops->release(mdev);
 
+	if (likely(parent->ops->notifier)) {
+		if (vfio_unregister_notifier(&mdev->dev, &mdev->nb))
+			pr_err("Failed to unregister notifier for mdev\n");
+	}
+
 	module_put(THIS_MODULE);
 }
 
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index ec819e9a115a..94c43034c297 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 */