Message-Id: <20220510061738.2761430-9-baolu.lu@linux.intel.com>
Date:   Tue, 10 May 2022 14:17:34 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     Joerg Roedel <joro@...tes.org>, Jason Gunthorpe <jgg@...dia.com>,
        Christoph Hellwig <hch@...radead.org>,
        Kevin Tian <kevin.tian@...el.com>,
        Ashok Raj <ashok.raj@...el.com>, Will Deacon <will@...nel.org>,
        Robin Murphy <robin.murphy@....com>,
        Jean-Philippe Brucker <jean-philippe@...aro.com>,
        Dave Jiang <dave.jiang@...el.com>,
        Vinod Koul <vkoul@...nel.org>
Cc:     Eric Auger <eric.auger@...hat.com>, Liu Yi L <yi.l.liu@...el.com>,
        Jacob jun Pan <jacob.jun.pan@...el.com>,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        Lu Baolu <baolu.lu@...ux.intel.com>
Subject: [PATCH v6 08/12] iommu/sva: Use attach/detach_pasid_dev in SVA interfaces

The existing iommu SVA interfaces are implemented by calling the SVA
specific iommu ops provided by the IOMMU drivers. There's no need for
any SVA specific ops in iommu_ops vector anymore as we can achieve
this through the generic attach/detach_dev_pasid domain ops.

This refactors the IOMMU SVA interfaces implementation by using the
attach/detach_pasid_dev ops and align them with the concept of the
iommu domain. Put the new SVA code in the sva related file in order
to make it self-contained.

Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
---
 include/linux/iommu.h         |  44 ++++++-----
 drivers/iommu/iommu-sva-lib.c | 145 ++++++++++++++++++++++++++++++++++
 drivers/iommu/iommu.c         |  92 ---------------------
 3 files changed, 168 insertions(+), 113 deletions(-)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 2921e634491e..5a3ef4d58b1f 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -684,12 +684,6 @@ int iommu_dev_enable_feature(struct device *dev, enum iommu_dev_features f);
 int iommu_dev_disable_feature(struct device *dev, enum iommu_dev_features f);
 bool iommu_dev_feature_enabled(struct device *dev, enum iommu_dev_features f);
 
-struct iommu_sva *iommu_sva_bind_device(struct device *dev,
-					struct mm_struct *mm,
-					void *drvdata);
-void iommu_sva_unbind_device(struct iommu_sva *handle);
-u32 iommu_sva_get_pasid(struct iommu_sva *handle);
-
 int iommu_device_use_default_domain(struct device *dev);
 void iommu_device_unuse_default_domain(struct device *dev);
 
@@ -1031,21 +1025,6 @@ iommu_dev_disable_feature(struct device *dev, enum iommu_dev_features feat)
 	return -ENODEV;
 }
 
-static inline struct iommu_sva *
-iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata)
-{
-	return NULL;
-}
-
-static inline void iommu_sva_unbind_device(struct iommu_sva *handle)
-{
-}
-
-static inline u32 iommu_sva_get_pasid(struct iommu_sva *handle)
-{
-	return IOMMU_PASID_INVALID;
-}
-
 static inline struct iommu_fwspec *dev_iommu_fwspec_get(struct device *dev)
 {
 	return NULL;
@@ -1087,6 +1066,29 @@ static inline void iommu_detach_device_pasid(struct iommu_domain *domain,
 }
 #endif /* CONFIG_IOMMU_API */
 
+#ifdef CONFIG_IOMMU_SVA
+struct iommu_sva *iommu_sva_bind_device(struct device *dev,
+					struct mm_struct *mm,
+					void *drvdata);
+void iommu_sva_unbind_device(struct iommu_sva *handle);
+u32 iommu_sva_get_pasid(struct iommu_sva *handle);
+#else /* CONFIG_IOMMU_SVA */
+static inline struct iommu_sva *
+iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata)
+{
+	return NULL;
+}
+
+static inline void iommu_sva_unbind_device(struct iommu_sva *handle)
+{
+}
+
+static inline u32 iommu_sva_get_pasid(struct iommu_sva *handle)
+{
+	return IOMMU_PASID_INVALID;
+}
+#endif /* CONFIG_IOMMU_SVA */
+
 /**
  * iommu_map_sgtable - Map the given buffer to the IOMMU domain
  * @domain:	The IOMMU domain to perform the mapping
diff --git a/drivers/iommu/iommu-sva-lib.c b/drivers/iommu/iommu-sva-lib.c
index 106506143896..e7301514f286 100644
--- a/drivers/iommu/iommu-sva-lib.c
+++ b/drivers/iommu/iommu-sva-lib.c
@@ -3,6 +3,8 @@
  * Helpers for IOMMU drivers implementing SVA
  */
 #include <linux/mutex.h>
+#include <linux/iommu.h>
+#include <linux/slab.h>
 #include <linux/sched/mm.h>
 
 #include "iommu-sva-lib.h"
@@ -69,3 +71,146 @@ struct mm_struct *iommu_sva_find(ioasid_t pasid)
 	return ioasid_find(&iommu_sva_pasid, pasid, __mmget_not_zero);
 }
 EXPORT_SYMBOL_GPL(iommu_sva_find);
+
+/*
+ * IOMMU SVA driver-oriented interfaces
+ */
+static struct iommu_domain *
+iommu_sva_alloc_domain(struct device *dev, struct mm_struct *mm)
+{
+	struct bus_type *bus = dev->bus;
+	struct iommu_domain *domain;
+
+	if (!bus || !bus->iommu_ops)
+		return NULL;
+
+	domain = bus->iommu_ops->domain_alloc(IOMMU_DOMAIN_SVA);
+	if (!domain)
+		return NULL;
+
+	mmgrab(mm);
+	domain->mm = mm;
+	domain->type = IOMMU_DOMAIN_SVA;
+
+	return domain;
+}
+
+static void iommu_sva_free_domain(struct iommu_domain *domain)
+{
+	mmdrop(domain->mm);
+	iommu_domain_free(domain);
+}
+
+/**
+ * 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 mm_users
+ * @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
+ * @mm, it is returned and an additional reference is taken. Caller must call
+ * iommu_sva_unbind_device() to release each reference.
+ *
+ * iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA) must be called first, to
+ * initialize the required SVA features.
+ *
+ * On error, returns an ERR_PTR value.
+ */
+struct iommu_sva *
+iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata)
+{
+	int ret = -EINVAL;
+	struct iommu_sva *handle;
+	struct iommu_domain *domain;
+
+	/*
+	 * TODO: Remove the drvdata parameter after kernel PASID support is
+	 * enabled for the idxd driver.
+	 */
+	if (drvdata)
+		return ERR_PTR(-EOPNOTSUPP);
+
+	/* Allocate mm->pasid if necessary. */
+	ret = iommu_sva_alloc_pasid(mm, 1, (1U << dev->iommu->pasid_bits) - 1);
+	if (ret)
+		return ERR_PTR(ret);
+
+	mutex_lock(&iommu_sva_lock);
+	/* Search for an existing bond. */
+	handle = xa_load(&dev->iommu->sva_bonds, mm->pasid);
+	if (handle) {
+		refcount_inc(&handle->users);
+		goto out_success;
+	}
+
+	handle = kzalloc(sizeof(*handle), GFP_KERNEL);
+	if (!handle) {
+		ret = -ENOMEM;
+		goto out_unlock;
+	}
+
+	domain = iommu_sva_alloc_domain(dev, mm);
+	if (!domain) {
+		ret = -ENODEV;
+		goto out_free_bond;
+	}
+
+	ret = iommu_attach_device_pasid(domain, dev, mm->pasid);
+	if (ret)
+		goto out_free_domain;
+
+	handle->dev = dev;
+	handle->domain = domain;
+	refcount_set(&handle->users, 1);
+	ret = xa_err(xa_store(&dev->iommu->sva_bonds, mm->pasid,
+			      handle, GFP_KERNEL));
+	if (ret)
+		goto out_detach_domain;
+
+out_success:
+	mutex_unlock(&iommu_sva_lock);
+	return handle;
+
+out_detach_domain:
+	iommu_detach_device_pasid(domain, dev, mm->pasid);
+out_free_domain:
+	iommu_sva_free_domain(domain);
+out_free_bond:
+	kfree(handle);
+out_unlock:
+	mutex_unlock(&iommu_sva_lock);
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(iommu_sva_bind_device);
+
+/**
+ * iommu_sva_unbind_device() - Remove a bond created with iommu_sva_bind_device
+ * @handle: the handle returned by iommu_sva_bind_device()
+ *
+ * Put reference to a bond between device and address space. The device should
+ * not be issuing any more transaction for this PASID. All outstanding page
+ * requests for this PASID must have been flushed to the IOMMU.
+ */
+void iommu_sva_unbind_device(struct iommu_sva *handle)
+{
+	struct device *dev = handle->dev;
+	struct iommu_domain *domain = handle->domain;
+	ioasid_t pasid = iommu_sva_get_pasid(handle);
+
+	mutex_lock(&iommu_sva_lock);
+	if (refcount_dec_and_test(&handle->users)) {
+		xa_erase(&dev->iommu->sva_bonds, pasid);
+		iommu_detach_device_pasid(domain, dev, pasid);
+		iommu_sva_free_domain(domain);
+		kfree(handle);
+	}
+	mutex_unlock(&iommu_sva_lock);
+}
+EXPORT_SYMBOL_GPL(iommu_sva_unbind_device);
+
+u32 iommu_sva_get_pasid(struct iommu_sva *handle)
+{
+	return handle->domain->mm->pasid;
+}
+EXPORT_SYMBOL_GPL(iommu_sva_get_pasid);
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 1abff5fc9554..367d0ecf6e12 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2734,98 +2734,6 @@ bool iommu_dev_feature_enabled(struct device *dev, enum iommu_dev_features feat)
 }
 EXPORT_SYMBOL_GPL(iommu_dev_feature_enabled);
 
-/**
- * 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
- * @mm, it is returned and an additional reference is taken. Caller must call
- * iommu_sva_unbind_device() to release each reference.
- *
- * iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA) must be called first, to
- * initialize the required SVA features.
- *
- * On error, returns an ERR_PTR value.
- */
-struct iommu_sva *
-iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata)
-{
-	struct iommu_group *group;
-	struct iommu_sva *handle = ERR_PTR(-EINVAL);
-	const struct iommu_ops *ops = dev_iommu_ops(dev);
-
-	if (!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);
-	iommu_group_put(group);
-
-	return handle;
-}
-EXPORT_SYMBOL_GPL(iommu_sva_bind_device);
-
-/**
- * iommu_sva_unbind_device() - Remove a bond created with iommu_sva_bind_device
- * @handle: the handle returned by iommu_sva_bind_device()
- *
- * Put reference to a bond between device and address space. The device should
- * not be issuing any more transaction for this PASID. All outstanding page
- * requests for this PASID must have been flushed to the IOMMU.
- */
-void iommu_sva_unbind_device(struct iommu_sva *handle)
-{
-	struct iommu_group *group;
-	struct device *dev = handle->dev;
-	const struct iommu_ops *ops = dev_iommu_ops(dev);
-
-	if (!ops->sva_unbind)
-		return;
-
-	group = iommu_group_get(dev);
-	if (!group)
-		return;
-
-	mutex_lock(&group->mutex);
-	ops->sva_unbind(handle);
-	mutex_unlock(&group->mutex);
-
-	iommu_group_put(group);
-}
-EXPORT_SYMBOL_GPL(iommu_sva_unbind_device);
-
-u32 iommu_sva_get_pasid(struct iommu_sva *handle)
-{
-	const struct iommu_ops *ops = dev_iommu_ops(handle->dev);
-
-	if (!ops->sva_get_pasid)
-		return IOMMU_PASID_INVALID;
-
-	return ops->sva_get_pasid(handle);
-}
-EXPORT_SYMBOL_GPL(iommu_sva_get_pasid);
-
 /*
  * Changes the default domain of an iommu group that has *only* one device
  *
-- 
2.25.1

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