Messages in this thread | | | From | "Tian, Kevin" <> | Subject | RE: [PATCH v7 09/11] iommu/vt-d: Add bind guest PASID support | Date | Fri, 25 Oct 2019 07:19:26 +0000 |
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> From: Jacob Pan [mailto:jacob.jun.pan@linux.intel.com] > Sent: Friday, October 25, 2019 3:55 AM > > When supporting guest SVA with emulated IOMMU, the guest PASID > table is shadowed in VMM. Updates to guest vIOMMU PASID table > will result in PASID cache flush which will be passed down to > the host as bind guest PASID calls.
will be translated into binding/unbinding guest PASID calls to update the host shadow PASID table.
> > For the SL page tables, it will be harvested from device's > default domain (request w/o PASID), or aux domain in case of > mediated device.
harvested -> copied or linked to?
> > .-------------. .---------------------------. > | vIOMMU | | Guest process CR3, FL only| > | | '---------------------------' > .----------------/ > | PASID Entry |--- PASID cache flush - > '-------------' | > | | V > | | CR3 in GPA > '-------------' > Guest > ------| Shadow |--------------------------|-------- > v v v > Host > .-------------. .----------------------. > | pIOMMU | | Bind FL for GVA-GPA | > | | '----------------------' > .----------------/ | > | PASID Entry | V (Nested xlate) > '----------------\.------------------------------. > | | |SL for GPA-HPA, default domain| > | | '------------------------------' > '-------------' > Where: > - FL = First level/stage one page tables > - SL = Second level/stage two page tables > > Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> > Signed-off-by: Liu, Yi L <yi.l.liu@linux.intel.com> > --- > drivers/iommu/intel-iommu.c | 4 + > drivers/iommu/intel-svm.c | 184 > ++++++++++++++++++++++++++++++++++++++++++++ > include/linux/intel-iommu.h | 8 +- > include/linux/intel-svm.h | 17 ++++ > 4 files changed, 212 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > index acd1ac787d8b..5fab32fbc4b4 100644 > --- a/drivers/iommu/intel-iommu.c > +++ b/drivers/iommu/intel-iommu.c > @@ -6026,6 +6026,10 @@ const struct iommu_ops intel_iommu_ops = { > .dev_disable_feat = intel_iommu_dev_disable_feat, > .is_attach_deferred = intel_iommu_is_attach_deferred, > .pgsize_bitmap = INTEL_IOMMU_PGSIZES, > +#ifdef CONFIG_INTEL_IOMMU_SVM > + .sva_bind_gpasid = intel_svm_bind_gpasid, > + .sva_unbind_gpasid = intel_svm_unbind_gpasid, > +#endif
again, pure PASID management logic should be separated from SVM.
> }; > > static void quirk_iommu_igfx(struct pci_dev *dev) > diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c > index a18b02a9709d..ae13a310cf96 100644 > --- a/drivers/iommu/intel-svm.c > +++ b/drivers/iommu/intel-svm.c > @@ -216,6 +216,190 @@ static LIST_HEAD(global_svm_list); > list_for_each_entry(sdev, &svm->devs, list) \ > if (dev == sdev->dev) \ > > +int intel_svm_bind_gpasid(struct iommu_domain *domain, > + struct device *dev, > + struct iommu_gpasid_bind_data *data) > +{ > + struct intel_iommu *iommu = intel_svm_device_to_iommu(dev); > + struct dmar_domain *ddomain; > + struct intel_svm_dev *sdev; > + struct intel_svm *svm; > + int ret = 0; > + > + if (WARN_ON(!iommu) || !data) > + return -EINVAL; > + > + if (data->version != IOMMU_GPASID_BIND_VERSION_1 || > + data->format != IOMMU_PASID_FORMAT_INTEL_VTD) > + return -EINVAL; > + > + if (dev_is_pci(dev)) { > + /* VT-d supports devices with full 20 bit PASIDs only */ > + if (pci_max_pasids(to_pci_dev(dev)) != PASID_MAX) > + return -EINVAL; > + }
what about non-pci devices? It just moves forward w/o any check here?
> + > + /* > + * We only check host PASID range, we have no knowledge to check > + * guest PASID range nor do we use the guest PASID. > + */ > + if (data->hpasid <= 0 || data->hpasid >= PASID_MAX) > + return -EINVAL; > + > + ddomain = to_dmar_domain(domain); > + /* REVISIT: > + * Sanity check adddress width and paging mode support > + * width matching in two dimensions: > + * 1. paging mode CPU <= IOMMU > + * 2. address width Guest <= Host. > + */
Is lacking of above logic harmful? If not, we should add
> + mutex_lock(&pasid_mutex); > + svm = ioasid_find(NULL, data->hpasid, NULL); > + if (IS_ERR(svm)) { > + ret = PTR_ERR(svm); > + goto out; > + } > + if (svm) { > + /* > + * If we found svm for the PASID, there must be at > + * least one device bond, otherwise svm should be freed. > + */ > + BUG_ON(list_empty(&svm->devs)); > + > + for_each_svm_dev(svm, dev) { > + /* In case of multiple sub-devices of the same pdev > assigned, we should > + * allow multiple bind calls with the same PASID and > pdev. > + */ > + sdev->users++; > + goto out;
sorry if I overlooked, but I didn't see any check on the PASID actually belonging to this process. At least should check the match between svm->mm and get_task_mm? also check whether a previous binding between this hpasid and gpasid already exists.
> + } > + } else { > + /* We come here when PASID has never been bond to a > device. */ > + svm = kzalloc(sizeof(*svm), GFP_KERNEL); > + if (!svm) { > + ret = -ENOMEM; > + goto out; > + } > + /* REVISIT: upper layer/VFIO can track host process that > bind the PASID. > + * ioasid_set = mm might be sufficient for vfio to check > pasid VMM > + * ownership. > + */
Is it correct to leave the check to the caller?
> + svm->mm = get_task_mm(current); > + svm->pasid = data->hpasid; > + if (data->flags & IOMMU_SVA_GPASID_VAL) { > + svm->gpasid = data->gpasid; > + svm->flags |= SVM_FLAG_GUEST_PASID; > + } > + ioasid_set_data(data->hpasid, svm); > + INIT_LIST_HEAD_RCU(&svm->devs); > + INIT_LIST_HEAD(&svm->list); > + > + mmput(svm->mm); > + } > + sdev = kzalloc(sizeof(*sdev), GFP_KERNEL); > + if (!sdev) { > + if (list_empty(&svm->devs)) > + kfree(svm); > + ret = -ENOMEM; > + goto out; > + } > + sdev->dev = dev; > + sdev->users = 1; > + > + /* Set up device context entry for PASID if not enabled already */ > + ret = intel_iommu_enable_pasid(iommu, sdev->dev); > + if (ret) { > + dev_err(dev, "Failed to enable PASID capability\n"); > + kfree(sdev); > + goto out; > + } > + > + /* > + * For guest bind, we need to set up PASID table entry as follows: > + * - FLPM matches guest paging mode > + * - turn on nested mode > + * - SL guest address width matching > + */ > + ret = intel_pasid_setup_nested(iommu, > + dev, > + (pgd_t *)data->gpgd, > + data->hpasid, > + &data->vtd, > + ddomain, > + data->addr_width); > + if (ret) { > + dev_err(dev, "Failed to set up PASID %llu in nested mode, > Err %d\n", > + data->hpasid, ret); > + kfree(sdev);
disable pasid? revert ioasid_set_data?
> + goto out; > + } > + svm->flags |= SVM_FLAG_GUEST_MODE; > + > + init_rcu_head(&sdev->rcu); > + list_add_rcu(&sdev->list, &svm->devs); > + out: > + mutex_unlock(&pasid_mutex); > + return ret; > +} > + > +int intel_svm_unbind_gpasid(struct device *dev, int pasid) > +{ > + struct intel_svm_dev *sdev; > + struct intel_iommu *iommu; > + struct intel_svm *svm; > + int ret = -EINVAL; > + > + mutex_lock(&pasid_mutex); > + iommu = intel_svm_device_to_iommu(dev); > + if (!iommu) > + goto out; > + > + svm = ioasid_find(NULL, pasid, NULL); > + if (IS_ERR_OR_NULL(svm)) { > + ret = PTR_ERR(svm); > + goto out; > + } > + > + for_each_svm_dev(svm, dev) { > + ret = 0; > + sdev->users--; > + if (!sdev->users) { > + list_del_rcu(&sdev->list); > + intel_pasid_tear_down_entry(iommu, dev, svm- > >pasid); > + /* TODO: Drain in flight PRQ for the PASID since it > + * may get reused soon, we don't want to > + * confuse with its previous life. > + * intel_svm_drain_prq(dev, pasid); > + */ > + kfree_rcu(sdev, rcu); > + > + if (list_empty(&svm->devs)) { > + list_del(&svm->list); > + kfree(svm); > + /* > + * We do not free PASID here until explicit > call > + * from VFIO to free. The PASID life cycle > + * management is largely tied to VFIO > management > + * of assigned device life cycles. In case of > + * guest exit without a explicit free PASID call, > + * the responsibility lies in VFIO layer to free > + * the PASIDs allocated for the guest. > + * For security reasons, VFIO has to track the > + * PASID ownership per guest anyway to > ensure > + * that PASID allocated by one guest cannot > be > + * used by another. > + */ > + ioasid_set_data(pasid, NULL); > + } > + } > + break; > + } > + out: > + mutex_unlock(&pasid_mutex); > + > + return ret; > +} > + > int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct > svm_dev_ops *ops) > { > struct intel_iommu *iommu = intel_svm_device_to_iommu(dev); > diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h > index 3dba6ad3e9ad..6c74c71b1ebf 100644 > --- a/include/linux/intel-iommu.h > +++ b/include/linux/intel-iommu.h > @@ -673,7 +673,9 @@ int intel_iommu_enable_pasid(struct intel_iommu > *iommu, struct device *dev); > int intel_svm_init(struct intel_iommu *iommu); > extern int intel_svm_enable_prq(struct intel_iommu *iommu); > extern int intel_svm_finish_prq(struct intel_iommu *iommu); > - > +extern int intel_svm_bind_gpasid(struct iommu_domain *domain, > + struct device *dev, struct iommu_gpasid_bind_data *data); > +extern int intel_svm_unbind_gpasid(struct device *dev, int pasid); > struct svm_dev_ops; > > struct intel_svm_dev { > @@ -690,9 +692,13 @@ struct intel_svm_dev { > struct intel_svm { > struct mmu_notifier notifier; > struct mm_struct *mm; > + > struct intel_iommu *iommu; > int flags; > int pasid; > + int gpasid; /* Guest PASID in case of vSVA bind with non-identity > host > + * to guest PASID mapping. > + */ > struct list_head devs; > struct list_head list; > }; > diff --git a/include/linux/intel-svm.h b/include/linux/intel-svm.h > index 94f047a8a845..a2c189ad0b01 100644 > --- a/include/linux/intel-svm.h > +++ b/include/linux/intel-svm.h > @@ -44,6 +44,23 @@ struct svm_dev_ops { > * do such IOTLB flushes automatically. > */ > #define SVM_FLAG_SUPERVISOR_MODE (1<<1) > +/* > + * The SVM_FLAG_GUEST_MODE flag is used when a guest process bind to > a device. > + * In this case the mm_struct is in the guest kernel or userspace, its life > + * cycle is managed by VMM and VFIO layer. For IOMMU driver, this API > provides > + * means to bind/unbind guest CR3 with PASIDs allocated for a device. > + */ > +#define SVM_FLAG_GUEST_MODE (1<<2) > +/* > + * The SVM_FLAG_GUEST_PASID flag is used when a guest has its own > PASID space, > + * which requires guest and host PASID translation at both directions. We > keep > + * track of guest PASID in order to provide lookup service to device drivers. > + * One such example is a physical function (PF) driver that supports > mediated > + * device (mdev) assignment. Guest programming of mdev configuration > space can > + * only be done with guest PASID, therefore PF driver needs to find the > matching > + * host PASID to program the real hardware. > + */ > +#define SVM_FLAG_GUEST_PASID (1<<3) > > #ifdef CONFIG_INTEL_IOMMU_SVM > > -- > 2.7.4
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