RE: [PATCH 2/9] iommu/vt-d: Decouple idr bond pointer from svm

From: Liu, Yi L
Date: Tue May 01 2018 - 05:21:44 EST


> From: Lu Baolu [mailto:baolu.lu@xxxxxxxxxxxxxxx]
> Sent: Tuesday, April 17, 2018 11:03 AM
> Subject: [PATCH 2/9] iommu/vt-d: Decouple idr bond pointer from svm
>
> As we move the PASID idr out of SVM code and make it serving
> as a global PASID name space, the consumer can specify a ptr
> to bind it with a PASID. We shouldn't assume that each PASID
> will be bond with a ptr of struct intel_svm anymore.
> This patch cleans up a idr_for_each_entry() usage in the SVM
> code. It's required to replace the SVM-specific idr with the
> global PASID idr.
>
> Cc: Ashok Raj <ashok.raj@xxxxxxxxx>
> Cc: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
> Cc: Liu Yi L <yi.l.liu@xxxxxxxxx>
> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>

Looks good to me.
Reviewed-by: Liu, Yi L <yi.l.liu@xxxxxxxxx>

Regards,
Yi Liu
> drivers/iommu/intel-svm.c | 14 ++++++++++----
> include/linux/intel-iommu.h | 1 +
> 2 files changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
> index e8cd984..983af0c 100644
> --- a/drivers/iommu/intel-svm.c
> +++ b/drivers/iommu/intel-svm.c
> @@ -298,6 +298,7 @@ static const struct mmu_notifier_ops intel_mmuops = {
> };
>
> static DEFINE_MUTEX(pasid_mutex);
> +static LIST_HEAD(global_svm_list);
>
> int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_ops
> *ops)
> {
> @@ -329,13 +330,13 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int
> flags, struct svm_dev_
>
> mutex_lock(&pasid_mutex);
> if (pasid && !(flags & SVM_FLAG_PRIVATE_PASID)) {
> - int i;
> + struct intel_svm *t;
>
> - idr_for_each_entry(&iommu->pasid_idr, svm, i) {
> - if (svm->mm != mm ||
> - (svm->flags & SVM_FLAG_PRIVATE_PASID))
> + list_for_each_entry(t, &global_svm_list, list) {
> + if (t->mm != mm || (t->flags & SVM_FLAG_PRIVATE_PASID))
> continue;
>
> + svm = t;
> if (svm->pasid >= pasid_max) {
> dev_warn(dev,
> "Limited PASID width. Cannot use existing
> PASID %d\n",
> @@ -404,6 +405,7 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int
> flags, struct svm_dev_
> svm->mm = mm;
> svm->flags = flags;
> INIT_LIST_HEAD_RCU(&svm->devs);
> + INIT_LIST_HEAD(&svm->list);
> ret = -ENOMEM;
> if (mm) {
> ret = mmu_notifier_register(&svm->notifier, mm);
> @@ -430,6 +432,8 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int
> flags, struct svm_dev_
> */
> if (cap_caching_mode(iommu->cap))
> intel_flush_pasid_dev(svm, sdev, svm->pasid);
> +
> + list_add_tail(&svm->list, &global_svm_list);
> }
> list_add_rcu(&sdev->list, &svm->devs);
>
> @@ -485,6 +489,8 @@ int intel_svm_unbind_mm(struct device *dev, int pasid)
> if (svm->mm)
> mmu_notifier_unregister(&svm-
> >notifier, svm->mm);
>
> + list_del(&svm->list);
> +
> /* We mandate that no page faults may be
> outstanding
> * for the PASID when
> intel_svm_unbind_mm() is called.
> * If that is not obeyed, subtle errors will
> happen.
> diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
> index ef169d6..795717e 100644
> --- a/include/linux/intel-iommu.h
> +++ b/include/linux/intel-iommu.h
> @@ -486,6 +486,7 @@ struct intel_svm {
> int flags;
> int pasid;
> struct list_head devs;
> + struct list_head list;
> };
>
> extern int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct
> intel_svm_dev *sdev);
> --
> 2.7.4