Subject: Re: linux-next: manual merge of the iommufd tree with the iommu tree

From: Stephen Rothwell <[email-masked]>
Date: Fri, 3 Nov 2023 10:53:55 +1100

Hi all,

On Wed, 25 Oct 2023 15:44:20 +1100 Stephen Rothwell <[email-masked]> wrote:
>
> Today's linux-next merge of the iommufd tree got a conflict in:
> 
>   include/linux/iommu.h
> 
> between commits:
> 
>   1c68cbc64fe6 ("iommu: Add IOMMU_DOMAIN_PLATFORM")
>   4601cd2d7c4c ("iommu: Add ops->domain_alloc_paging()")
> 
> from the iommu tree and commits:
> 
>   1621aef1fbfe ("iommu: Add IOMMU_DOMAIN_NESTED")
>   909f4abd1097 ("iommu: Add new iommu op to create domains owned by userspace")
>   17dd7701a2e7 ("iommu: Pass in parent domain with user_data to domain_alloc_user op")
> 
> from the iommufd tree.
> 
> I fixed it up (see below) and can carry the fix as necessary. This
> is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging.  You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.
> 
> -- 
> Cheers,
> Stephen Rothwell
> 
> diff --cc include/linux/iommu.h
> index b5b254e205c6,f347bf31761f..000000000000
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@@ -64,8 -66,10 +66,11 @@@ struct iommu_domain_geometry 
>   #define __IOMMU_DOMAIN_DMA_FQ	(1U << 3)  /* DMA-API uses flush queue    */
>   
>   #define __IOMMU_DOMAIN_SVA	(1U << 4)  /* Shared process address space */
>  +#define __IOMMU_DOMAIN_PLATFORM	(1U << 5)
>   
> + #define __IOMMU_DOMAIN_NESTED	(1U << 5)  /* User-managed address space nested
> + 					      on a stage-2 translation        */
> + 
>   #define IOMMU_DOMAIN_ALLOC_FLAGS ~__IOMMU_DOMAIN_DMA_FQ
>   /*
>    * This are the possible domain-types
> @@@ -94,7 -96,7 +99,8 @@@
>   				 __IOMMU_DOMAIN_DMA_API |	\
>   				 __IOMMU_DOMAIN_DMA_FQ)
>   #define IOMMU_DOMAIN_SVA	(__IOMMU_DOMAIN_SVA)
>  +#define IOMMU_DOMAIN_PLATFORM	(__IOMMU_DOMAIN_PLATFORM)
> + #define IOMMU_DOMAIN_NESTED	(__IOMMU_DOMAIN_NESTED)
>   
>   struct iommu_domain {
>   	unsigned type;
> @@@ -238,9 -327,19 +331,21 @@@ static inline int __iommu_copy_struct_f
>    *           op is allocated in the iommu driver and freed by the caller after
>    *           use. The information type is one of enum iommu_hw_info_type defined
>    *           in include/uapi/linux/iommufd.h.
> -  * @domain_alloc: allocate iommu domain
> +  * @domain_alloc: allocate and return an iommu domain if success. Otherwise
> +  *                NULL is returned. The domain is not fully initialized until
> +  *                the caller iommu_domain_alloc() returns.
>  + * @domain_alloc_paging: Allocate an iommu_domain that can be used for
>  + *                       UNMANAGED, DMA, and DMA_FQ domain types.
> +  * @domain_alloc_user: Allocate an iommu domain corresponding to the input
> +  *                     parameters as defined in include/uapi/linux/iommufd.h.
> +  *                     Unlike @domain_alloc, it is called only by IOMMUFD and
> +  *                     must fully initialize the new domain before return.
> +  *                     Upon success, if the @user_data is valid and the @parent
> +  *                     points to a kernel-managed domain, the new domain must be
> +  *                     IOMMU_DOMAIN_NESTED type; otherwise, the @parent must be
> +  *                     NULL while the @user_data can be optionally provided, the
> +  *                     new domain must support __IOMMU_DOMAIN_PAGING.
> +  *                     Upon failure, ERR_PTR must be returned.
>    * @probe_device: Add device to iommu driver handling
>    * @release_device: Remove device from iommu driver handling
>    * @probe_finalize: Do final setup work after the device is added to an IOMMU
> @@@ -275,7 -372,9 +380,10 @@@ struct iommu_ops 
>   
>   	/* Domain allocation and freeing by the iommu driver */
>   	struct iommu_domain *(*domain_alloc)(unsigned iommu_domain_type);
>  +	struct iommu_domain *(*domain_alloc_paging)(struct device *dev);
> + 	struct iommu_domain *(*domain_alloc_user)(
> + 		struct device *dev, u32 flags, struct iommu_domain *parent,
> + 		const struct iommu_user_data *user_data);
>   
>   	struct iommu_device *(*probe_device)(struct device *dev);
>   	void (*release_device)(struct device *dev);

This is now a conflict between the iommu tree and Linus' tree.

-- 
Cheers,
Stephen Rothwell