Re: [PATCH v4 1/2] xen/passthrough: Provide stub functions when !HAS_PASSTHROUGH

[Julien Grall <julien@xxxxxxx>]

On 07/03/2025 09:20, Luca Fancellu wrote:
> > On 7 Mar 2025, at 09:09, Julien Grall <julien@xxxxxxx> wrote:
> > >   /*
> > >    * 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
>   */
That's fine with me. The iommu code is technically maintained by Jan, so 
I will wait for him to confirm he is fine with the patch before committing.
Cheers,

--
Julien Grall