iommu: Add group variant for SVA bind/unbind

maillist inclusion
category: feature
bugzilla: 51855
CVE: NA

Reference: https://jpbrucker.net/git/linux/commit/?h=sva/2021-03-01&id=7984f27d63b2f56dcdc106be9484061b3a13df0b

---------------------------------------------

VFIO works directly with IOMMU groups rather than devices. Even if groups
ar still required to only contain one device in order to use SVA, add a
set of helpers for VFIO.
Signed-off-by: NJean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: NLijun Fang <fanglijun3@huawei.com>
Reviewed-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/iommu/iommu.c

@@ -3067,6 +3067,55 @@ int iommu_aux_get_pasid(struct iommu_domain *domain, struct device *dev)
 }
 EXPORT_SYMBOL_GPL(iommu_aux_get_pasid);
 
+struct iommu_sva_bind_group_data {
+	struct mm_struct *mm;
+	struct iommu_sva *handle;
+	void *drvdata;
+};
+
+static int iommu_group_do_bind_dev(struct device *dev, void *data)
+{
+	struct iommu_sva_bind_group_data *bind = data;
+	const struct iommu_ops *ops = dev->bus->iommu_ops;
+
+	if (!ops || !ops->sva_bind)
+		return -ENODEV;
+
+	bind->handle = ops->sva_bind(dev, bind->mm, bind->drvdata);
+	return PTR_ERR_OR_ZERO(bind->handle);
+}
+
+struct iommu_sva *
+iommu_sva_bind_group(struct iommu_group *group, struct mm_struct *mm,
+		     void *drvdata)
+{
+	int ret = -EINVAL;
+	struct iommu_sva_bind_group_data data = {
+		.mm = mm,
+		.drvdata = drvdata,
+	};
+
+	/* Ensure device count and domain don't change while we're binding */
+	mutex_lock(&group->mutex);
+
+	/*
+	 * To keep things simple, SVA currently doesn't support IOMMU groups
+	 * with more than one device. Existing SVA-capable systems are not
+	 * affected by the problems that required IOMMU groups (lack of ACS
+	 * isolation, device ID aliasing and other hardware issues).
+	 */
+	if (iommu_group_device_count(group) != 1)
+		goto out_unlock;
+
+	ret = __iommu_group_for_each_dev(group, &data,
+					 iommu_group_do_bind_dev);
+out_unlock:
+	mutex_unlock(&group->mutex);
+
+	return ret ? ERR_PTR(ret) : data.handle;
+}
+EXPORT_SYMBOL_GPL(iommu_sva_bind_group);
+
 /**
  * iommu_sva_bind_device() - Bind a process address space to a device
  * @dev: the device
@@ -3085,33 +3134,14 @@ EXPORT_SYMBOL_GPL(iommu_aux_get_pasid);
 struct iommu_sva *
 iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata)
 {
+	struct iommu_sva *handle;
 	struct iommu_group *group;
-	struct iommu_sva *handle = ERR_PTR(-EINVAL);
-	const struct iommu_ops *ops = dev->bus->iommu_ops;
-
-	if (!ops || !ops->sva_bind)
-		return ERR_PTR(-ENODEV);
 
 	group = iommu_group_get(dev);
 	if (!group)
 		return ERR_PTR(-ENODEV);
 
-	/* Ensure device count and domain don't change while we're binding */
-	mutex_lock(&group->mutex);
-
-	/*
-	 * To keep things simple, SVA currently doesn't support IOMMU groups
-	 * with more than one device. Existing SVA-capable systems are not
-	 * affected by the problems that required IOMMU groups (lack of ACS
-	 * isolation, device ID aliasing and other hardware issues).
-	 */
-	if (iommu_group_device_count(group) != 1)
-		goto out_unlock;
-
-	handle = ops->sva_bind(dev, mm, drvdata);
-
-out_unlock:
-	mutex_unlock(&group->mutex);
+	handle = iommu_sva_bind_group(group, mm, drvdata);
 	iommu_group_put(group);
 
 	return handle;

include/linux/iommu.h

@@ -666,6 +666,9 @@ int iommu_aux_get_pasid(struct iommu_domain *domain, struct device *dev);
 struct iommu_sva *iommu_sva_bind_device(struct device *dev,
 					struct mm_struct *mm,
 					void *drvdata);
+extern struct iommu_sva *
+iommu_sva_bind_group(struct iommu_group *group, struct mm_struct *mm,
+		     void *drvdata);
 void iommu_sva_unbind_device(struct iommu_sva *handle);
 u32 iommu_sva_get_pasid(struct iommu_sva *handle);
 
@@ -1107,6 +1110,13 @@ int iommu_attach_pasid_table(struct iommu_domain *domain,
 static inline
 void iommu_detach_pasid_table(struct iommu_domain *domain) {}
 
+static inline struct iommu_sva *
+iommu_sva_bind_group(struct iommu_group *group, struct mm_struct *mm,
+		     void *drvdata)
+{
+	return -ENODEV;
+}
+
 #endif /* CONFIG_IOMMU_API */
 
 /**