[Intel-gfx] [PATCH 1/2] vfio: Replace the DMA unmapping notifier with a callback

[Christoph Hellwig]

On Mon, Jun 06, 2022 at 09:34:35PM -0300, Jason Gunthorpe wrote:
> +static void intel_vgpu_dma_unmap(struct vfio_device *vfio_dev, u64 iova,
> +				 u64 length)
>  {
> +	struct intel_vgpu *vgpu = vfio_dev_to_vgpu(vfio_dev);
> +	struct gvt_dma *entry;
> +	u64 iov_pfn, end_iov_pfn;
>  
> +	iov_pfn = iova >> PAGE_SHIFT;
> +	end_iov_pfn = iov_pfn + length / PAGE_SIZE;

I'd just initialize these at declaration time.  The mix between
shifting and division here is also kind weird, but we probably
shouldn't change too much from the original version.

> +	/* Vendor drivers MUST unpin pages in response to an invalidation. */

s/Vendor//g

>  /**
> + * vfio_ap_mdev_dma_unmap - Notifier that IOVA has been unmapped
> + * @vdev: The VFIO device
> + * @unmap: IOVA range unmapped
>   *
> + * Unpin the guest IOVA (the NIB guest address we pinned before).
>   */

kerneldoc comments for method instances are a bit silly..

> +static int vfio_iommu_notifier(struct notifier_block *nb, unsigned long action,
> +			       void *data)
> +{
> +	struct vfio_device *vfio_device =
> +		container_of(nb, struct vfio_device, iommu_nb);
> +	struct vfio_iommu_type1_dma_unmap *unmap = data;

Using the iommu type 1 UAPI structure in the core vfio code for a
subset of its field is kinda weird.  But we can fix this later.

Otherwise looks good:

Reviewed-by: Christoph Hellwig <hch at lst.de>