> From: Baolu Lu <[email protected]>
> Sent: Saturday, October 21, 2023 11:08 AM
> 
> On 10/20/23 5:32 PM, Yi Liu wrote:
> > From: Lu Baolu <[email protected]>
> >
> > This adds the support for IOMMU_HWPT_DATA_VTD_S1 type.
> >
> > Signed-off-by: Lu Baolu <[email protected]>
> > Signed-off-by: Yi Liu <[email protected]>
> > ---
> >   drivers/iommu/intel/iommu.c | 39 ++++++++++++++++++++++++++-----------
> >   1 file changed, 28 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> > index b47025fbdea4..c7704e7efd4a 100644
> > --- a/drivers/iommu/intel/iommu.c
> > +++ b/drivers/iommu/intel/iommu.c
> > @@ -4076,7 +4076,7 @@ intel_iommu_domain_alloc_user(struct device *dev, u32
> flags,
> >                           struct iommu_domain *parent,
> >                           const struct iommu_user_data *user_data)
> >   {
> > -   struct iommu_domain *domain;
> > +   bool request_nest_parent = flags & IOMMU_HWPT_ALLOC_NEST_PARENT;
> >     struct intel_iommu *iommu;
> >
> >     if (flags & (~IOMMU_HWPT_ALLOC_NEST_PARENT))
> > @@ -4086,18 +4086,35 @@ intel_iommu_domain_alloc_user(struct device *dev, 
> > u32
> flags,
> >     if (!iommu)
> >             return ERR_PTR(-ENODEV);
> >
> > -   if ((flags & IOMMU_HWPT_ALLOC_NEST_PARENT) && !ecap_nest(iommu-
> >ecap))
> > +   if (!user_data) { /* Must be PAGING domain */
> > +           struct iommu_domain *domain;
> > +
> > +           if (request_nest_parent && !ecap_nest(iommu->ecap))
> 
> Hardware capability is not sufficient. How about adding below helper:

Yes. But the sm_supported() seems a bit confusing. Is it? actually, it's
a combined check of the sm capability and software choice (use sm or
not). How about renaming it to be sm_enabled()? Although the best
enable status check is to read the SM bit in root address register. No hurry
in this circle, but may be nice to have.

> diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
> index b5f33a7c1973..b04bbabcd696 100644
> --- a/drivers/iommu/intel/iommu.h
> +++ b/drivers/iommu/intel/iommu.h
> @@ -540,6 +540,8 @@ enum {
>   #define sm_supported(iommu)    (intel_iommu_sm &&
> ecap_smts((iommu)->ecap))
>   #define pasid_supported(iommu) (sm_supported(iommu) &&                 \
>                                   ecap_pasid((iommu)->ecap))
> +#define nested_supported(iommu)        (sm_supported(iommu) &&
>         \
> +                                ecap_nest((iommu)->ecap))
> 
>   struct pasid_entry;
>   struct pasid_state_entry;
> 
> And, use nested_supported() here and bleow
> 
> > +                   return ERR_PTR(-EOPNOTSUPP);
> > +           if (parent)
> > +                   return ERR_PTR(-EINVAL);
> > +           /*
> > +            * domain_alloc_user op needs to fully initialize a domain
> > +            * before return, so uses iommu_domain_alloc() here for
> > +            * simple.
> > +            */
> > +           domain = iommu_domain_alloc(dev->bus);
> > +           if (!domain)
> > +                   return ERR_PTR(-ENOMEM);
> > +           return domain;
> > +   }
> > +
> > +   /* Must be nested domain */
> > +   if (!ecap_nest(iommu->ecap))
> 
> ...here.
> 
> > +           return ERR_PTR(-EOPNOTSUPP);
> > +   if (user_data->type != IOMMU_HWPT_DATA_VTD_S1)
> >             return ERR_PTR(-EOPNOTSUPP);
> > +   if (!parent || parent->ops != intel_iommu_ops.default_domain_ops)
> > +           return ERR_PTR(-EINVAL);
> > +   if (request_nest_parent)
> > +           return ERR_PTR(-EINVAL);
> >
> > -   /*
> > -    * domain_alloc_user op needs to fully initialize a domain
> > -    * before return, so uses iommu_domain_alloc() here for
> > -    * simple.
> > -    */
> > -   domain = iommu_domain_alloc(dev->bus);
> > -   if (!domain)
> > -           domain = ERR_PTR(-ENOMEM);
> > -   return domain;
> > +   return intel_nested_domain_alloc(parent, user_data);
> >   }
> >
> >   static void intel_iommu_domain_free(struct iommu_domain *domain)
> 
> Best regards,
> baolu

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