> From: Lu Baolu <baolu...@linux.intel.com>
> Sent: Sunday, June 28, 2020 8:34 AM
> 
> After a page request is handled, software must response the device which
> raised the page request with the handling result. This is done through
> the iommu ops.page_response if the request was reported to outside of
> vendor iommu driver through iommu_report_device_fault(). This adds the
> VT-d implementation of page_response ops.
> 
> Co-developed-by: Jacob Pan <jacob.jun....@linux.intel.com>
> Signed-off-by: Jacob Pan <jacob.jun....@linux.intel.com>
> Co-developed-by: Liu Yi L <yi.l....@intel.com>
> Signed-off-by: Liu Yi L <yi.l....@intel.com>
> Signed-off-by: Lu Baolu <baolu...@linux.intel.com>
> ---
>  drivers/iommu/intel/iommu.c |  1 +
>  drivers/iommu/intel/svm.c   | 73
> +++++++++++++++++++++++++++++++++++++
>  include/linux/intel-iommu.h |  3 ++
>  3 files changed, 77 insertions(+)
> 
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index de17952ed133..7eb29167e8f9 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -6057,6 +6057,7 @@ const struct iommu_ops intel_iommu_ops = {
>       .sva_bind               = intel_svm_bind,
>       .sva_unbind             = intel_svm_unbind,
>       .sva_get_pasid          = intel_svm_get_pasid,
> +     .page_response          = intel_svm_page_response,
>  #endif
>  };
> 
> diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
> index 4800bb6f8794..003ea9579632 100644
> --- a/drivers/iommu/intel/svm.c
> +++ b/drivers/iommu/intel/svm.c
> @@ -1092,3 +1092,76 @@ int intel_svm_get_pasid(struct iommu_sva *sva)
> 
>       return pasid;
>  }
> +
> +int intel_svm_page_response(struct device *dev,
> +                         struct iommu_fault_event *evt,
> +                         struct iommu_page_response *msg)
> +{
> +     struct iommu_fault_page_request *prm;
> +     struct intel_svm_dev *sdev;
> +     struct intel_iommu *iommu;
> +     struct intel_svm *svm;
> +     bool private_present;
> +     bool pasid_present;
> +     bool last_page;
> +     u8 bus, devfn;
> +     int ret = 0;
> +     u16 sid;
> +
> +     if (!dev || !dev_is_pci(dev))
> +             return -ENODEV;
> +
> +     iommu = device_to_iommu(dev, &bus, &devfn);
> +     if (!iommu)
> +             return -ENODEV;

move to the place when iommu is referenced. This place is too early.

> +
> +     if (!msg || !evt)
> +             return -EINVAL;
> +
> +     mutex_lock(&pasid_mutex);
> +
> +     prm = &evt->fault.prm;
> +     sid = PCI_DEVID(bus, devfn);
> +     pasid_present = prm->flags &
> IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
> +     private_present = prm->flags &
> IOMMU_FAULT_PAGE_REQUEST_PRIV_DATA;
> +     last_page = prm->flags &
> IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE;
> +
> +     if (pasid_present) {
> +             /* VT-d supports devices with full 20 bit PASIDs only */
> +             if (pci_max_pasids(to_pci_dev(dev)) != PASID_MAX) {
> +                     ret = -EINVAL;
> +                     goto out;
> +             }

shouldn't we check prm->pasid here? Above is more reasonable to be
checked when page request is reported.

> +
> +             ret = pasid_to_svm_sdev(dev, prm->pasid, &svm, &sdev);
> +             if (ret || !sdev)

if sdev==NULL, suppose an error (-ENODEV) should be returned here?

> +                     goto out;
> +     }
> +
> +     /*
> +      * Per VT-d spec. v3.0 ch7.7, system software must respond
> +      * with page group response if private data is present (PDP)
> +      * or last page in group (LPIG) bit is set. This is an
> +      * additional VT-d feature beyond PCI ATS spec.

feature->requirement

Thanks
Kevin

> +      */
> +     if (last_page || private_present) {
> +             struct qi_desc desc;
> +
> +             desc.qw0 = QI_PGRP_PASID(prm->pasid) | QI_PGRP_DID(sid)
> |
> +                             QI_PGRP_PASID_P(pasid_present) |
> +                             QI_PGRP_PDP(private_present) |
> +                             QI_PGRP_RESP_CODE(msg->code) |
> +                             QI_PGRP_RESP_TYPE;
> +             desc.qw1 = QI_PGRP_IDX(prm->grpid) |
> QI_PGRP_LPIG(last_page);
> +             desc.qw2 = 0;
> +             desc.qw3 = 0;
> +             if (private_present)
> +                     memcpy(&desc.qw2, prm->private_data,
> +                            sizeof(prm->private_data));
> +
> +             qi_submit_sync(iommu, &desc, 1, 0);
> +     }
> +out:
> +     mutex_unlock(&pasid_mutex);
> +     return ret;
> +}
> diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
> index fc2cfc3db6e1..bf6009a344f5 100644
> --- a/include/linux/intel-iommu.h
> +++ b/include/linux/intel-iommu.h
> @@ -741,6 +741,9 @@ struct iommu_sva *intel_svm_bind(struct device
> *dev, struct mm_struct *mm,
>                                void *drvdata);
>  void intel_svm_unbind(struct iommu_sva *handle);
>  int intel_svm_get_pasid(struct iommu_sva *handle);
> +int intel_svm_page_response(struct device *dev, struct iommu_fault_event
> *evt,
> +                         struct iommu_page_response *msg);
> +
>  struct svm_dev_ops;
> 
>  struct intel_svm_dev {
> --
> 2.17.1

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