Re: [PATCH v8 7/9] vfio/mdev: Add iommu related member in mdev_device

[Kirti Wankhede]

On 3/25/2019 7:00 AM, Lu Baolu wrote:
> A parent device might create different types of mediated
> devices. For example, a mediated device could be created
> by the parent device with full isolation and protection
> provided by the IOMMU. One usage case could be found on
> Intel platforms where a mediated device is an assignable
> subset of a PCI, the DMA requests on behalf of it are all
> tagged with a PASID. Since IOMMU supports PASID-granular
> translations (scalable mode in VT-d 3.0), this mediated
> device could be individually protected and isolated by an
> IOMMU.
> 
> This patch adds a new member in the struct mdev_device to
> indicate that the mediated device represented by mdev could
> be isolated and protected by attaching a domain to a device
> represented by mdev->iommu_device. It also adds a helper to
> add or set the iommu device.
> 
> * mdev_device->iommu_device
>   - This, if set, indicates that the mediated device could
>     be fully isolated and protected by IOMMU via attaching
>     an iommu domain to this device. If empty, it indicates
>     using vendor defined isolation, hence bypass IOMMU.
> 
> * mdev_set/get_iommu_device(dev, iommu_device)
>   - Set or get the iommu device which represents this mdev
>     in IOMMU's device scope. Drivers don't need to set the
>     iommu device if it uses vendor defined isolation.
> 
> Cc: Ashok Raj <ashok.raj@xxxxxxxxx>
> Cc: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
> Cc: Liu Yi L <yi.l.liu@xxxxxxxxx>
> Suggested-by: Kevin Tian <kevin.tian@xxxxxxxxx>
> Suggested-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Reviewed-by: Jean-Philippe Brucker <jean-philippe.brucker@xxxxxxx>
> ---
>  drivers/vfio/mdev/mdev_core.c    | 18 ++++++++++++++++++
>  drivers/vfio/mdev/mdev_private.h |  1 +
>  include/linux/mdev.h             | 14 ++++++++++++++
>  3 files changed, 33 insertions(+)
> 
> diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
> index b96fedc77ee5..1b6435529166 100644
> --- a/drivers/vfio/mdev/mdev_core.c
> +++ b/drivers/vfio/mdev/mdev_core.c
> @@ -390,6 +390,24 @@ int mdev_device_remove(struct device *dev, bool force_remove)
>  	return 0;
>  }
>  
> +int mdev_set_iommu_device(struct device *dev, struct device *iommu_device)
> +{
> +	struct mdev_device *mdev = to_mdev_device(dev);
> +
> +	mdev->iommu_device = iommu_device;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(mdev_set_iommu_device);
> +
> +struct device *mdev_get_iommu_device(struct device *dev)
> +{
> +	struct mdev_device *mdev = to_mdev_device(dev);
> +
> +	return mdev->iommu_device;
> +}
> +EXPORT_SYMBOL(mdev_get_iommu_device);
> +
>  static int __init mdev_init(void)
>  {
>  	return mdev_bus_register();
> diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
> index 379758c52b1b..bfb7b22a7cb6 100644
> --- a/drivers/vfio/mdev/mdev_private.h
> +++ b/drivers/vfio/mdev/mdev_private.h
> @@ -34,6 +34,7 @@ struct mdev_device {
>  	struct list_head next;
>  	struct kobject *type_kobj;
>  	bool active;
> +	struct device *iommu_device;
>  };
>  
>  #define to_mdev_device(dev)	container_of(dev, struct mdev_device, dev)
> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
> index d7aee90e5da5..df2ea39f47ee 100644
> --- a/include/linux/mdev.h
> +++ b/include/linux/mdev.h
> @@ -15,6 +15,20 @@
>  
>  struct mdev_device;
>  
> +/*
> + * Called by the parent device driver to set the device which represents
> + * this mdev in iommu protection scope. By default, the iommu device is
> + * NULL, that indicates using vendor defined isolation.
> + *
> + * @dev: the mediated device that iommu will isolate.
> + * @iommu_device: a pci device which represents the iommu for @dev.
> + *
> + * Return 0 for success, otherwise negative error value.
> + */
> +int mdev_set_iommu_device(struct device *dev, struct device *iommu_device);
> +
> +struct device *mdev_get_iommu_device(struct device *dev);
> +
>  /**
>   * struct mdev_parent_ops - Structure to be registered for each parent device to
>   * register the device to mdev module.
> 

Reviewed-by: Kirti Wankhede <kwankhede@xxxxxxxxxx>

Thanks,
Kirti