Re: [Xen-devel] [PATCH V3 1/8] iommu/arm: Add iommu_helpers.c file to keep common for IOMMUs stuff

[Julien Grall <julien.grall@xxxxxxx>]

Hi Oleksandr,

On 8/20/19 7:09 PM, Oleksandr Tyshchenko wrote:
> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
>
> Introduce a separate file to keep various helpers which could be used
> by more than one IOMMU driver in order not to duplicate code.
>
> The first candidates to be moved to the new file are SMMU driver's
> "map_page/unmap_page" callbacks. There callbacks neither contain any
s/There/These/ I think.

> SMMU specific info nor perform any SMMU specific actions and are going
> to be the same across all IOMMU drivers which H/W IP shares P2M
> with the CPU like SMMU does.
>
> So, move callbacks to iommu_helpers.c for the upcoming IPMMU driver
> to be able to re-use them.
>
> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
> CC: Julien Grall <julien.grall@xxxxxxx>
[...]

>   static __init const struct arm_smmu_device *find_smmu(const struct device 
> *dev)
> diff --git a/xen/include/asm-arm/iommu.h b/xen/include/asm-arm/iommu.h
> index 904c9ae..20d865e 100644
> --- a/xen/include/asm-arm/iommu.h
> +++ b/xen/include/asm-arm/iommu.h
> @@ -26,6 +26,13 @@ struct arch_iommu
>   const struct iommu_ops *iommu_get_ops(void);
>   void iommu_set_ops(const struct iommu_ops *ops);
>   
> +/* mapping helpers */
I would specify this only works when the PT is shared between the IOMMU 
and CPU.
With the two requests addressed:

Acked-by: Julien Grall <julien.grall@xxxxxxx>

> +int __must_check arm_iommu_map_page(struct domain *d, dfn_t dfn, mfn_t mfn,
> +                                    unsigned int flags,
> +                                    unsigned int *flush_flags);
> +int __must_check arm_iommu_unmap_page(struct domain *d, dfn_t dfn,
> +                                      unsigned int *flush_flags);
> +
>   #endif /* __ARCH_ARM_IOMMU_H__ */
>   
>   /*
Cheers,

--
Julien Grall

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