[RFC PATCH v3 04/12] iommu: Add a map_pages() op for IOMMU drivers

[Will Deacon]

On Mon, Apr 05, 2021 at 12:11:04PM -0700, Isaac J. Manjarres wrote:
> Add a callback for IOMMU drivers to provide a path for the
> IOMMU framework to call into an IOMMU driver, which can
> call into the io-pgtable code, to map a physically contiguous
> rnage of pages of the same size.
> 
> For IOMMU drivers that do not specify a map_pages() callback,
> the existing logic of mapping memory one page block at a time
> will be used.
> 
> Signed-off-by: Isaac J. Manjarres <isaacm at codeaurora.org>
> Suggested-by: Will Deacon <will at kernel.org>
> ---
>  include/linux/iommu.h | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index 9cf81242581a..528d6a58479e 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -192,6 +192,8 @@ struct iommu_iotlb_gather {
>   * @attach_dev: attach device to an iommu domain
>   * @detach_dev: detach device from an iommu domain
>   * @map: map a physically contiguous memory region to an iommu domain
> + * @map_pages: map a physically contiguous set of pages of the same size to
> + *             an iommu domain.
>   * @unmap: unmap a physically contiguous memory region from an iommu domain
>   * @unmap_pages: unmap a number of pages of the same size from an iommu domain
>   * @flush_iotlb_all: Synchronously flush all hardware TLBs for this domain
> @@ -244,6 +246,9 @@ struct iommu_ops {
>  	void (*detach_dev)(struct iommu_domain *domain, struct device *dev);
>  	int (*map)(struct iommu_domain *domain, unsigned long iova,
>  		   phys_addr_t paddr, size_t size, int prot, gfp_t gfp);
> +	int (*map_pages)(struct iommu_domain *domain, unsigned long iova,
> +			 phys_addr_t paddr, size_t pgsize, size_t pgcount,
> +			 int prot, gfp_t gfp, size_t *mapped);

(same comment as for the io-pgtable callback).

Will