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

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Date:   Thu, 15 Mar 2018 10:38:20 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     David Woodhouse <dwmw2@...radead.org>,
        Joerg Roedel <joro@...tes.org>
Cc:     ashok.raj@...el.com, sanjay.k.kumar@...el.com,
        jacob.jun.pan@...el.com, kevin.tian@...el.com, yi.l.liu@...el.com,
        yi.y.sun@...el.com, iommu@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org, Lu Baolu <baolu.lu@...ux.intel.com>,
        Jacob Pan <jacob.jun.pan@...ux.intel.com>
Subject: [PATCH 2/3] 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@...el.com>
Cc: Jacob Pan <jacob.jun.pan@...ux.intel.com>
Cc: Kevin Tian <kevin.tian@...el.com>
Cc: Liu Yi L <yi.l.liu@...el.com>

Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@...el.com>
---
 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