Hi Yi,

Missing a proper commit message. You can comment on the fact you only
support the case where all the physical iomms have the same CAP/ECAP MASKS

On 7/12/20 1:21 PM, Liu Yi L wrote:
> Cc: Kevin Tian <kevin.t...@intel.com>
> CC: Jacob Pan <jacob.jun....@linux.intel.com>
> Cc: Alex Williamson <alex.william...@redhat.com>
> Cc: Eric Auger <eric.au...@redhat.com>
> Cc: Jean-Philippe Brucker <jean-phili...@linaro.org>
> Cc: Joerg Roedel <j...@8bytes.org>
> Cc: Lu Baolu <baolu...@linux.intel.com>
> Signed-off-by: Liu Yi L <yi.l....@intel.com>
> Signed-off-by: Jacob Pan <jacob.jun....@linux.intel.com>
> ---
> v2 -> v3:
> *) remove cap/ecap_mask in iommu_nesting_info.
> ---
>  drivers/iommu/intel/iommu.c | 81 
> +++++++++++++++++++++++++++++++++++++++++++--
>  include/linux/intel-iommu.h | 16 +++++++++
>  2 files changed, 95 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index a9504cb..9f7ad1a 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -5659,12 +5659,16 @@ static inline bool iommu_pasid_support(void)
>  static inline bool nested_mode_support(void)
>  {
>       struct dmar_drhd_unit *drhd;
> -     struct intel_iommu *iommu;
> +     struct intel_iommu *iommu, *prev = NULL;
>       bool ret = true;
>  
>       rcu_read_lock();
>       for_each_active_iommu(iommu, drhd) {
> -             if (!sm_supported(iommu) || !ecap_nest(iommu->ecap)) {
> +             if (!prev)
> +                     prev = iommu;
> +             if (!sm_supported(iommu) || !ecap_nest(iommu->ecap) ||
> +                 (VTD_CAP_MASK & (iommu->cap ^ prev->cap)) ||
> +                 (VTD_ECAP_MASK & (iommu->ecap ^ prev->ecap))) {
>                       ret = false;
>                       break;>                 }
> @@ -6079,6 +6083,78 @@ intel_iommu_domain_set_attr(struct iommu_domain 
> *domain,
>       return ret;
>  }
>  
> +static int intel_iommu_get_nesting_info(struct iommu_domain *domain,
> +                                     struct iommu_nesting_info *info)
> +{
> +     struct dmar_domain *dmar_domain = to_dmar_domain(domain);
> +     u64 cap = VTD_CAP_MASK, ecap = VTD_ECAP_MASK;
> +     struct device_domain_info *domain_info;
> +     struct iommu_nesting_info_vtd vtd;
> +     unsigned long flags;
> +     unsigned int size;
> +
> +     if (domain->type != IOMMU_DOMAIN_UNMANAGED ||
> +         !(dmar_domain->flags & DOMAIN_FLAG_NESTING_MODE))
> +             return -ENODEV;
> +
> +     if (!info)
> +             return -EINVAL;
> +
> +     size = sizeof(struct iommu_nesting_info) +
> +             sizeof(struct iommu_nesting_info_vtd);
> +     /*
> +      * if provided buffer size is smaller than expected, should
> +      * return 0 and also the expected buffer size to caller.
> +      */
> +     if (info->size < size) {
> +             info->size = size;
> +             return 0;
> +     }
> +
> +     spin_lock_irqsave(&device_domain_lock, flags);
> +     /*
> +      * arbitrary select the first domain_info as all nesting
> +      * related capabilities should be consistent across iommu
> +      * units.
> +      */
> +     domain_info = list_first_entry(&dmar_domain->devices,
> +                                    struct device_domain_info, link);
> +     cap &= domain_info->iommu->cap;
> +     ecap &= domain_info->iommu->ecap;
> +     spin_unlock_irqrestore(&device_domain_lock, flags);
> +
> +     info->format = IOMMU_PASID_FORMAT_INTEL_VTD;
> +     info->features = IOMMU_NESTING_FEAT_SYSWIDE_PASID |
> +                      IOMMU_NESTING_FEAT_BIND_PGTBL |
> +                      IOMMU_NESTING_FEAT_CACHE_INVLD;
> +     info->addr_width = dmar_domain->gaw;
> +     info->pasid_bits = ilog2(intel_pasid_max_id);
> +     info->padding = 0;
> +     vtd.flags = 0;
> +     vtd.padding = 0;
> +     vtd.cap_reg = cap;
> +     vtd.ecap_reg = ecap;
> +
> +     memcpy(info->data, &vtd, sizeof(vtd));
> +     return 0;
> +}
> +
> +static int intel_iommu_domain_get_attr(struct iommu_domain *domain,
> +                                    enum iommu_attr attr, void *data)
> +{
> +     switch (attr) {
> +     case DOMAIN_ATTR_NESTING:
> +     {
> +             struct iommu_nesting_info *info =
> +                             (struct iommu_nesting_info *)data;
> +
> +             return intel_iommu_get_nesting_info(domain, info);
> +     }
> +     default:
> +             return -ENODEV;
-ENOENT?
> +     }
> +}
> +
>  /*
>   * Check that the device does not live on an external facing PCI port that is
>   * marked as untrusted. Such devices should not be able to apply quirks and
> @@ -6101,6 +6177,7 @@ const struct iommu_ops intel_iommu_ops = {
>       .domain_alloc           = intel_iommu_domain_alloc,
>       .domain_free            = intel_iommu_domain_free,
>       .domain_set_attr        = intel_iommu_domain_set_attr,
> +     .domain_get_attr        = intel_iommu_domain_get_attr,
>       .attach_dev             = intel_iommu_attach_device,
>       .detach_dev             = intel_iommu_detach_device,
>       .aux_attach_dev         = intel_iommu_aux_attach_device,
> diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
> index 18f292e..c4ed0d4 100644
> --- a/include/linux/intel-iommu.h
> +++ b/include/linux/intel-iommu.h
> @@ -197,6 +197,22 @@
>  #define ecap_max_handle_mask(e) ((e >> 20) & 0xf)
>  #define ecap_sc_support(e)   ((e >> 7) & 0x1) /* Snooping Control */
>  
> +/* Nesting Support Capability Alignment */
> +#define VTD_CAP_FL1GP                BIT_ULL(56)
> +#define VTD_CAP_FL5LP                BIT_ULL(60)
> +#define VTD_ECAP_PRS         BIT_ULL(29)
> +#define VTD_ECAP_ERS         BIT_ULL(30)
> +#define VTD_ECAP_SRS         BIT_ULL(31)
> +#define VTD_ECAP_EAFS                BIT_ULL(34)
> +#define VTD_ECAP_PASID               BIT_ULL(40)

> +
> +/* Only capabilities marked in below MASKs are reported */
> +#define VTD_CAP_MASK         (VTD_CAP_FL1GP | VTD_CAP_FL5LP)
> +
> +#define VTD_ECAP_MASK                (VTD_ECAP_PRS | VTD_ECAP_ERS | \
> +                              VTD_ECAP_SRS | VTD_ECAP_EAFS | \
> +                              VTD_ECAP_PASID)
> +
>  /* Virtual command interface capability */
>  #define vccap_pasid(v)               (((v) & DMA_VCS_PAS)) /* PASID 
> allocation */
>  
> 
Thanks

Eric


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