On 07.03.2025 12:23, Luca Fancellu wrote:
>>>>> +
>>>>> +static inline int iommu_domain_init(struct domain *d, unsigned int opts)
>>>>> +{
>>>>> + /*
>>>>> + * Return as the real iommu_domain_init() would: Success when
>>>>> + * !is_iommu_enabled(), following from !iommu_enabled when
>>>>> !HAS_PASSTHROUGH
>>>>> + */
>>>>> + return 0;
>>>>> +}
>>>>> +
>>>>> +static inline void iommu_hwdom_init(struct domain *d) {}
>>>>> +
>>>>> +static inline void iommu_domain_destroy(struct domain *d) {}
>>>>> +
>>>>> +#endif /* HAS_PASSTHROUGH */
>>>>> +
>>>>> /*
>>>>> * The following flags are passed to map (applicable ones also to unmap)
>>>>> * operations, while some are passed back by lookup operations.
>>>>> @@ -209,6 +233,8 @@ struct msi_msg;
>>>>> #ifdef CONFIG_HAS_DEVICE_TREE
>>>>> #include <xen/device_tree.h>
>>>>> +#ifdef CONFIG_HAS_PASSTHROUGH
>>>>> +
>>>>> int iommu_assign_dt_device(struct domain *d, struct dt_device_node *dev);
>>>>> int iommu_deassign_dt_device(struct domain *d, struct dt_device_node
>>>>> *dev);
>>>>> int iommu_dt_domain_init(struct domain *d);
>>>>> @@ -238,6 +264,26 @@ int iommu_do_dt_domctl(struct xen_domctl *domctl,
>>>>> struct domain *d,
>>>>> */
>>>>> int iommu_remove_dt_device(struct dt_device_node *np);
>>>>> +#else
>>>>> +
>>>>> +static inline int iommu_assign_dt_device(struct domain *d,
>>>>> + struct dt_device_node *dev)
>>>>> +{
>>>>> + return -EINVAL;
>>>>> +}
>>>>> +
>>>>> +static inline int iommu_add_dt_device(struct dt_device_node *np)
>>>>> +{
>>>>> + return 1;
>>>>
>>>> I would suggest to add a comment explain what 1 means. IIRC, this means
>>>> "no iommu" present.
>>>
>>> Would it be ok something like in iommu_domain_init:
>>>
>>> /*
>>> * Returns as the real iommu_add_dt_device() would: Error “no iommu" because
>>> * !iommu_enabled due to the fact that !HAS_PASSTHROUGH
>>> */
>>
>> We had been there before, hadn't we? Personally I find the suggested text
>> hard to follow.
>
> well, I’ve taken your suggestion for iommu_domain_init and adapted here,
> maybe the adaptation didn’t meet your criteria then :)
I wasn't overly happy with that other comment either.
> But ...
>
>> How about
>>
>> /*
>> * !HAS_PASSTHROUGH => !iommu_enabled (see the non-stub
>> * iommu_add_dt_device())
>> */
>>
>> If that's too terse, adding a few words should be fine.
>
> as long as you are happy with that, I’m happy as well, please let me know
> if you want a v5 with this or if you would do the modificaiton on commit.
I first need to get to looking at v4 as a whole.
Jan
