On Sat, 28 Mar 2020 08:02:01 +0000 "Tian, Kevin" <[email protected]> wrote:
> > From: Jacob Pan <[email protected]> > > Sent: Saturday, March 21, 2020 7:28 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. > > > > 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. > > > > .-------------. .---------------------------. > > | 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 <[email protected]> > > Signed-off-by: Liu, Yi L <[email protected]> > > --- > > drivers/iommu/intel-iommu.c | 4 + > > drivers/iommu/intel-svm.c | 224 > > ++++++++++++++++++++++++++++++++++++++++++++ > > include/linux/intel-iommu.h | 8 +- > > include/linux/intel-svm.h | 17 ++++ > > 4 files changed, 252 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/iommu/intel-iommu.c > > b/drivers/iommu/intel-iommu.c index e599b2537b1c..b1477cd423dd > > 100644 --- a/drivers/iommu/intel-iommu.c > > +++ b/drivers/iommu/intel-iommu.c > > @@ -6203,6 +6203,10 @@ 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 > > }; > > > > static void quirk_iommu_igfx(struct pci_dev *dev) > > diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c > > index d7f2a5358900..47c0deb5ae56 100644 > > --- a/drivers/iommu/intel-svm.c > > +++ b/drivers/iommu/intel-svm.c > > @@ -226,6 +226,230 @@ static LIST_HEAD(global_svm_list); > > list_for_each_entry((sdev), &(svm)->devs, list) \ > > if ((d) != (sdev)->dev) {} else > > > > +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; > > what about the full name e.g. dmar_domain? though a bit longer > but clearer than ddomain. > Sure, I don't have preference. > > + 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; > > + } else { > > + return -ENOTSUPP; > > + } > > + > > + /* > > + * 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); > > + > > + /* Sanity check paging mode support match between host and > > guest */ > > + if (data->addr_width == ADDR_WIDTH_5LEVEL && > > + !cap_5lp_support(iommu->cap)) { > > + pr_err("Cannot support 5 level paging requested by > > guest!\n"); > > + return -EINVAL; > > + } > > -ENOTSUPP? I was thinking from this API p.o.v, the input is invalid. Since both cap and addr_width are derived from input arguments. > > > + > > + 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. > > + */ > > + if (WARN_ON(list_empty(&svm->devs))) { > > + ret = -EINVAL; > > + goto out; > > + } > > + > > + if (svm->mm == get_task_mm(current) && > > + data->hpasid == svm->pasid && > > + data->gpasid == svm->gpasid) { > > + pr_warn("Cannot bind the same guest-host > > PASID for the same process\n"); > > Sorry I didn’t get the rationale here. Isn't this branch is for > binding the same PASID to multiple devices? In that case definitely > it is binding the same guest-host PASID for the same process. > otherwise if hpasid is different then you'll hit a different > intel_svm, while if gpasid is different how you can use one intel_svm > to hold multiple gpasids? > > I feel the error condition should be the opposite. and suppose > SVM_FLAG_ GUEST_PASID should be verified before checking gpasid. > You are right, actually we don't need the check here. The scenario for multiple devices bind to the same PASID is checked in for_each_svm_dev() I will remove this code. > > + mmput(svm->mm); > > + ret = -EINVAL; > > + goto out; > > + } > > + mmput(current->mm); > > + > > + for_each_svm_dev(sdev, 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. > > Does sub-device mean mdev? I didn't find such notation in current > iommu directory. > yes it is intended for mdev. > and to make it clearer, "In case of multiple mdevs of the same pdev > assigned to the same guest process". > I am avoiding mdev on purpose since it is not a concept in iommu driver. sub-device is more generic. > > + */ > > + sdev->users++; > > + goto out; > > + } > > + } 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. > > + */ > > Above message is unclear about what should be revisited. Does it > describe the current implementation or the expected revision in the > future? > What I meant was if VFIO can check PASID-mm ownership by itself, then we don;t have to store svm->mm here. Will drop the line below. I will add this comment to clarify. > > + 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); > > + mmput(svm->mm); > > + } > > + sdev = kzalloc(sizeof(*sdev), GFP_KERNEL); > > + if (!sdev) { > > + if (list_empty(&svm->devs)) { > > + ioasid_set_data(data->hpasid, NULL); > > + 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); > > + /* > > + * If this this a new PASID that never bond to a > > device, then > > + * the device list must be empty which indicates > > struct svm > > + * was allocated in this function. > > + */ > > the comment better move to the 1st occurrence when sdev allocation > fails. or even better put it in out label... > Sounds good. > > + if (list_empty(&svm->devs)) { > > + ioasid_set_data(data->hpasid, NULL); > > + kfree(svm); > > + } > > + 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 > > + */ > > looks above just explains the internal detail of > intel_pasid_setup_nested, which is not necessary to be here. > Right, will remove the comments. > > + ret = intel_pasid_setup_nested(iommu, > > + dev, > > + (pgd_t *)data->gpgd, > > + data->hpasid, > > + &data->vtd, > > + ddomain, > > + data->addr_width); > > It's worthy of an explanation here that setup_nested is required for > every device (even when they are sharing same intel_svm) because > we allocate pasid table per device. Otherwise I made a mistake to > think that only the 1st device bound to a new hpasid requires this > step. 😊 > Good suggestion, I will add the comments as: /* * PASID table is per device for better security. Therefore, for * each bind of a new device even with an existing PASID, we need to * call the nested mode setup function here. */ > > + if (ret) { > > + dev_err(dev, "Failed to set up PASID %llu in > > nested mode, Err %d\n", > > + data->hpasid, ret); > > + /* > > + * PASID entry should be in cleared state if > > nested mode > > + * set up failed. So we only need to clear IOASID > > tracking > > + * data such that free call will succeed. > > + */ > > + kfree(sdev); > > + if (list_empty(&svm->devs)) { > > + ioasid_set_data(data->hpasid, NULL); > > + kfree(svm); > > + } > > + 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_iommu *iommu = intel_svm_device_to_iommu(dev); > > + struct intel_svm_dev *sdev; > > + struct intel_svm *svm; > > + int ret = -EINVAL; > > + > > + if (WARN_ON(!iommu)) > > + return -EINVAL; > > + > > + mutex_lock(&pasid_mutex); > > + svm = ioasid_find(NULL, pasid, NULL); > > + if (!svm) { > > + ret = -EINVAL; > > + goto out; > > + } > > + > > + if (IS_ERR(svm)) { > > + ret = PTR_ERR(svm); > > + goto out; > > + } > > + > > + for_each_svm_dev(sdev, 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)) { > > + /* > > + * 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. > > As commented in other patches, VFIO is only one example user of this > API... > Right, how about this: /* * We do not free the IOASID here in that * IOMMU driver did not allocate it. * Unlike native SVM, IOASID for guest use was * allocated prior to the bind call. * In any case, if the free call comes before * the unbind, IOMMU driver will get notified * and perform cleanup. */ > > + */ > > + ioasid_set_data(pasid, NULL); > > + kfree(svm); > > + } > > + } > > + break; > > + } > > what about no dev match? an -EINVAL is also required then. > Yes, ret is initialized as -EINVAL > > +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 eda1d6687144..85b05120940e > > 100644 --- a/include/linux/intel-iommu.h > > +++ b/include/linux/intel-iommu.h > > @@ -681,7 +681,9 @@ struct dmar_domain *find_domain(struct device > > *dev); > > extern void intel_svm_check(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 { > > @@ -698,9 +700,13 @@ 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. > > + */ > > we don't need to highlight identity or non-identity thing, since > either way shares the same infrastructure here and it is not the > knowledge that the kernel driver should assume > Sorry, I don't get your point. What I meant was that this field "gpasid" is only used for non-identity case. For identity case, we don't have SVM_FLAG_GUEST_PASID. > > struct list_head devs; > > struct list_head list; > > }; > > diff --git a/include/linux/intel-svm.h b/include/linux/intel-svm.h > > index d7c403d0dd27..c19690937540 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 > [Jacob Pan] _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
