Messages in this thread |  | | Subject | Re: [PATCH v3 4/4] iommu/vt-d: Add page response ops support | From | Lu Baolu <> | Date | Fri, 10 Jul 2020 13:36:52 +0800 |
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Hi Kevin,
On 2020/7/10 10:42, Tian, Kevin wrote: >> From: Lu Baolu <baolu.lu@linux.intel.com> >> Sent: Thursday, July 9, 2020 3:06 PM >> >> After page requests are handled, software must respond to the device >> which raised the page request with the 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.pan@linux.intel.com> >> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> >> Co-developed-by: Liu Yi L <yi.l.liu@intel.com> >> Signed-off-by: Liu Yi L <yi.l.liu@intel.com> >> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> >> --- >> drivers/iommu/intel/iommu.c | 1 + >> drivers/iommu/intel/svm.c | 100 >> ++++++++++++++++++++++++++++++++++++ >> include/linux/intel-iommu.h | 3 ++ >> 3 files changed, 104 insertions(+) >> >> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c >> index 4a6b6960fc32..98390a6d8113 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 d24e71bac8db..839d2af377b6 100644 >> --- a/drivers/iommu/intel/svm.c >> +++ b/drivers/iommu/intel/svm.c >> @@ -1082,3 +1082,103 @@ 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 = NULL; >> + struct intel_svm *svm = NULL; >> + struct intel_iommu *iommu; >> + 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; >> + >> + 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) { >> + if (prm->pasid == 0 || prm->pasid >= PASID_MAX) { >> + ret = -EINVAL; >> + goto out; >> + } >> + >> + ret = pasid_to_svm_sdev(dev, prm->pasid, &svm, &sdev); >> + if (ret || !sdev) { >> + ret = -ENODEV; >> + goto out; >> + } >> + >> + /* >> + * For responses from userspace, need to make sure that the >> + * pasid has been bound to its mm. >> + */ >> + if (svm->flags & SVM_FLAG_GUEST_MODE) { >> + struct mm_struct *mm; >> + >> + mm = get_task_mm(current); >> + if (!mm) { >> + ret = -EINVAL; >> + goto out; >> + } >> + >> + if (mm != svm->mm) { >> + ret = -ENODEV; >> + mmput(mm); >> + goto out; >> + } >> + >> + mmput(mm); >> + } >> + } else { >> + pr_err_ratelimited("Invalid page response: no pasid\n"); >> + ret = -EINVAL; >> + goto out; > > check pasid=0 first, then no need to indent so many lines above.
Yes.
> >> + } >> + >> + /* >> + * 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 requirement beyond PCI ATS spec. >> + */ > > What is the behavior if system software doesn't follow the requirement? > en... maybe the question is really about whether the information in prm > comes from userspace or from internally-recorded info in iommu core. > The former cannot be trusted. The latter one is OK.
We require a page response when reporting such event. The upper layer (IOMMU core or VFIO) will be implemented with a timer, if userspace doesn't respond in time, the timer will get expired and a FAILURE response will be sent to device.
Best regards, baolu
> > 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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