iommu: Remove SVM_FLAG_SUPERVISOR_MODE support

The current kernel DMA with PASID support is based on the SVA with a flag
SVM_FLAG_SUPERVISOR_MODE. The IOMMU driver binds the kernel memory address
space to a PASID of the device. The device driver programs the device with
kernel virtual address (KVA) for DMA access. There have been security and
functional issues with this approach:

- The lack of IOTLB synchronization upon kernel page table updates.
  (vmalloc, module/BPF loading, CONFIG_DEBUG_PAGEALLOC etc.)
- Other than slight more protection, using kernel virtual address (KVA)
  has little advantage over physical address. There are also no use
  cases yet where DMA engines need kernel virtual addresses for in-kernel
  DMA.

This removes SVM_FLAG_SUPERVISOR_MODE support from the IOMMU interface.
The device drivers are suggested to handle kernel DMA with PASID through
the kernel DMA APIs.

The drvdata parameter in iommu_sva_bind_device() and all callbacks is not
needed anymore. Cleanup them as well.

Link: https://lore.kernel.org/linux-iommu/20210511194726.GP1002214@nvidia.com/
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Tested-by: Tony Zhu <tony.zhu@intel.com>
Link: https://lore.kernel.org/r/20221031005917.45690-4-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

8 files changed, 22 insertions, 79 deletions

diff --git a/drivers/dma/idxd/cdev.c b/drivers/dma/idxd/cdev.c
index c2808fd081d6..66720001ba1c 100644
--- a/drivers/dma/idxd/cdev.c
+++ b/drivers/dma/idxd/cdev.c
@@ -6,7 +6,6 @@
 #include <linux/pci.h>
 #include <linux/device.h>
 #include <linux/sched/task.h>
-#include <linux/intel-svm.h>
 #include <linux/io-64-nonatomic-lo-hi.h>
 #include <linux/cdev.h>
 #include <linux/fs.h>
@@ -100,7 +99,7 @@ static int idxd_cdev_open(struct inode *inode, struct file *filp)
 	filp->private_data = ctx;
 
 	if (device_user_pasid_enabled(idxd)) {
-		sva = iommu_sva_bind_device(dev, current->mm, NULL);
+		sva = iommu_sva_bind_device(dev, current->mm);
 		if (IS_ERR(sva)) {
 			rc = PTR_ERR(sva);
 			dev_err(dev, "pasid allocation failed: %d\n", rc);
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index 2b18d512cbfc..2c0fcfdc75c7 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -14,7 +14,6 @@
 #include <linux/io-64-nonatomic-lo-hi.h>
 #include <linux/device.h>
 #include <linux/idr.h>
-#include <linux/intel-svm.h>
 #include <linux/iommu.h>
 #include <uapi/linux/idxd.h>
 #include <linux/dmaengine.h>
@@ -502,29 +501,7 @@ static struct idxd_device *idxd_alloc(struct pci_dev *pdev, struct idxd_driver_d
 
 static int idxd_enable_system_pasid(struct idxd_device *idxd)
 {
-	int flags;
-	unsigned int pasid;
-	struct iommu_sva *sva;
-
-	flags = SVM_FLAG_SUPERVISOR_MODE;
-
-	sva = iommu_sva_bind_device(&idxd->pdev->dev, NULL, &flags);
-	if (IS_ERR(sva)) {
-		dev_warn(&idxd->pdev->dev,
-			 "iommu sva bind failed: %ld\n", PTR_ERR(sva));
-		return PTR_ERR(sva);
-	}
-
-	pasid = iommu_sva_get_pasid(sva);
-	if (pasid == IOMMU_PASID_INVALID) {
-		iommu_sva_unbind_device(sva);
-		return -ENODEV;
-	}
-
-	idxd->sva = sva;
-	idxd->pasid = pasid;
-	dev_dbg(&idxd->pdev->dev, "system pasid: %u\n", pasid);
-	return 0;
+	return -EOPNOTSUPP;
 }
 
 static void idxd_disable_system_pasid(struct idxd_device *idxd)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
index 5968a568aae2..8fcf0df4bd0e 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
@@ -367,8 +367,7 @@ err_free_bond:
 	return ERR_PTR(ret);
 }
 
-struct iommu_sva *
-arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm, void *drvdata)
+struct iommu_sva *arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm)
 {
 	struct iommu_sva *handle;
 	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index cd48590ada30..d2ba86470c42 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -754,8 +754,7 @@ bool arm_smmu_master_sva_enabled(struct arm_smmu_master *master);
 int arm_smmu_master_enable_sva(struct arm_smmu_master *master);
 int arm_smmu_master_disable_sva(struct arm_smmu_master *master);
 bool arm_smmu_master_iopf_supported(struct arm_smmu_master *master);
-struct iommu_sva *arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm,
-				    void *drvdata);
+struct iommu_sva *arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm);
 void arm_smmu_sva_unbind(struct iommu_sva *handle);
 u32 arm_smmu_sva_get_pasid(struct iommu_sva *handle);
 void arm_smmu_sva_notifier_synchronize(void);
@@ -791,7 +790,7 @@ static inline bool arm_smmu_master_iopf_supported(struct arm_smmu_master *master
 }
 
 static inline struct iommu_sva *
-arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm, void *drvdata)
+arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm)
 {
 	return ERR_PTR(-ENODEV);
 }
diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index cce0598f4109..33e5bcaf2a6c 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -748,8 +748,7 @@ struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devfn);
 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);
-struct iommu_sva *intel_svm_bind(struct device *dev, struct mm_struct *mm,
-				 void *drvdata);
+struct iommu_sva *intel_svm_bind(struct device *dev, struct mm_struct *mm);
 void intel_svm_unbind(struct iommu_sva *handle);
 u32 intel_svm_get_pasid(struct iommu_sva *handle);
 int intel_svm_page_response(struct device *dev, struct iommu_fault_event *evt,
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index 7d08eb034f2d..94bc47b68c93 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -296,8 +296,7 @@ out:
 	return 0;
 }
 
-static int intel_svm_alloc_pasid(struct device *dev, struct mm_struct *mm,
-				 unsigned int flags)
+static int intel_svm_alloc_pasid(struct device *dev, struct mm_struct *mm)
 {
 	ioasid_t max_pasid = dev_is_pci(dev) ?
 			pci_max_pasids(to_pci_dev(dev)) : intel_pasid_max_id;
@@ -307,8 +306,7 @@ static int intel_svm_alloc_pasid(struct device *dev, struct mm_struct *mm,
 
 static struct iommu_sva *intel_svm_bind_mm(struct intel_iommu *iommu,
 					   struct device *dev,
-					   struct mm_struct *mm,
-					   unsigned int flags)
+					   struct mm_struct *mm)
 {
 	struct device_domain_info *info = dev_iommu_priv_get(dev);
 	struct intel_svm_dev *sdev;
@@ -324,22 +322,18 @@ static struct iommu_sva *intel_svm_bind_mm(struct intel_iommu *iommu,
 
 		svm->pasid = mm->pasid;
 		svm->mm = mm;
-		svm->flags = flags;
 		INIT_LIST_HEAD_RCU(&svm->devs);
 
-		if (!(flags & SVM_FLAG_SUPERVISOR_MODE)) {
-			svm->notifier.ops = &intel_mmuops;
-			ret = mmu_notifier_register(&svm->notifier, mm);
-			if (ret) {
-				kfree(svm);
-				return ERR_PTR(ret);
-			}
+		svm->notifier.ops = &intel_mmuops;
+		ret = mmu_notifier_register(&svm->notifier, mm);
+		if (ret) {
+			kfree(svm);
+			return ERR_PTR(ret);
 		}
 
 		ret = pasid_private_add(svm->pasid, svm);
 		if (ret) {
-			if (svm->notifier.ops)
-				mmu_notifier_unregister(&svm->notifier, mm);
+			mmu_notifier_unregister(&svm->notifier, mm);
 			kfree(svm);
 			return ERR_PTR(ret);
 		}
@@ -374,9 +368,7 @@ static struct iommu_sva *intel_svm_bind_mm(struct intel_iommu *iommu,
 	}
 
 	/* Setup the pasid table: */
-	sflags = (flags & SVM_FLAG_SUPERVISOR_MODE) ?
-			PASID_FLAG_SUPERVISOR_MODE : 0;
-	sflags |= cpu_feature_enabled(X86_FEATURE_LA57) ? PASID_FLAG_FL5LP : 0;
+	sflags = cpu_feature_enabled(X86_FEATURE_LA57) ? PASID_FLAG_FL5LP : 0;
 	ret = intel_pasid_setup_first_level(iommu, dev, mm->pgd, mm->pasid,
 					    FLPT_DEFAULT_DID, sflags);
 	if (ret)
@@ -390,8 +382,7 @@ free_sdev:
 	kfree(sdev);
 free_svm:
 	if (list_empty(&svm->devs)) {
-		if (svm->notifier.ops)
-			mmu_notifier_unregister(&svm->notifier, mm);
+		mmu_notifier_unregister(&svm->notifier, mm);
 		pasid_private_remove(mm->pasid);
 		kfree(svm);
 	}
@@ -780,40 +771,20 @@ prq_advance:
 	return IRQ_RETVAL(handled);
 }
 
-struct iommu_sva *intel_svm_bind(struct device *dev, struct mm_struct *mm, void *drvdata)
+struct iommu_sva *intel_svm_bind(struct device *dev, struct mm_struct *mm)
 {
 	struct intel_iommu *iommu = device_to_iommu(dev, NULL, NULL);
-	unsigned int flags = 0;
 	struct iommu_sva *sva;
 	int ret;
 
-	if (drvdata)
-		flags = *(unsigned int *)drvdata;
-
-	if (flags & SVM_FLAG_SUPERVISOR_MODE) {
-		if (!ecap_srs(iommu->ecap)) {
-			dev_err(dev, "%s: Supervisor PASID not supported\n",
-				iommu->name);
-			return ERR_PTR(-EOPNOTSUPP);
-		}
-
-		if (mm) {
-			dev_err(dev, "%s: Supervisor PASID with user provided mm\n",
-				iommu->name);
-			return ERR_PTR(-EINVAL);
-		}
-
-		mm = &init_mm;
-	}
-
 	mutex_lock(&pasid_mutex);
-	ret = intel_svm_alloc_pasid(dev, mm, flags);
+	ret = intel_svm_alloc_pasid(dev, mm);
 	if (ret) {
 		mutex_unlock(&pasid_mutex);
 		return ERR_PTR(ret);
 	}
 
-	sva = intel_svm_bind_mm(iommu, dev, mm, flags);
+	sva = intel_svm_bind_mm(iommu, dev, mm);
 	mutex_unlock(&pasid_mutex);
 
 	return sva;
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 297ac79bc21c..a94ec648c88b 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2750,7 +2750,6 @@ EXPORT_SYMBOL_GPL(iommu_dev_disable_feature);
  * iommu_sva_bind_device() - Bind a process address space to a device
  * @dev: the device
  * @mm: the mm to bind, caller must hold a reference to it
- * @drvdata: opaque data pointer to pass to bind callback
  *
  * Create a bond between device and address space, allowing the device to access
  * the mm using the returned PASID. If a bond already exists between @device and
@@ -2763,7 +2762,7 @@ EXPORT_SYMBOL_GPL(iommu_dev_disable_feature);
  * On error, returns an ERR_PTR value.
  */
 struct iommu_sva *
-iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata)
+iommu_sva_bind_device(struct device *dev, struct mm_struct *mm)
 {
 	struct iommu_group *group;
 	struct iommu_sva *handle = ERR_PTR(-EINVAL);
@@ -2788,7 +2787,7 @@ iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata)
 	if (iommu_group_device_count(group) != 1)
 		goto out_unlock;
 
-	handle = ops->sva_bind(dev, mm, drvdata);
+	handle = ops->sva_bind(dev, mm);
 
 out_unlock:
 	mutex_unlock(&group->mutex);
diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c
index b70a013139c7..905eff1f840e 100644
--- a/drivers/misc/uacce/uacce.c
+++ b/drivers/misc/uacce/uacce.c
@@ -108,7 +108,7 @@ static int uacce_bind_queue(struct uacce_device *uacce, struct uacce_queue *q)
 	if (!(uacce->flags & UACCE_DEV_SVA))
 		return 0;
 
-	handle = iommu_sva_bind_device(uacce->parent, current->mm, NULL);
+	handle = iommu_sva_bind_device(uacce->parent, current->mm);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);