[PATCH 2/3] iommu/vt-d: Decouple idr bond pointer from svm

From: Lu Baolu
Date: Wed Mar 14 2018 - 22:46:32 EST


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>
---
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 99bc9bd..f3b7394 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",
@@ -403,6 +404,7 @@ 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);
@@ -433,6 +435,8 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
* anyway. Surely that can be left entirely to the guest? */
if (cap_caching_mode(iommu->cap))
intel_flush_pasid_dev(svm, sdev, 0);
+
+ list_add_tail(&svm->list, &global_svm_list);
}
list_add_rcu(&sdev->list, &svm->devs);

@@ -488,6 +492,8 @@ 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 bf83073..a2013dd 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