[PATCH v12 13/17] iommu/sva: Refactoring iommu_sva_bind/unbind_device()

Lu Baolu
2022-08-26T12:19:17Z

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
iommu_detach/detach_device_pasid interfaces and align them with the
concept of the SVA 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@linux.intel.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Tested-by: Tony Zhu <tony.zhu@intel.com>
---
include/linux/iommu.h | 43 ++++++-------
drivers/iommu/iommu-sva-lib.c | 110 ++++++++++++++++++++++++++++++++++
drivers/iommu/iommu.c | 91 ----------------------------
3 files changed, 133 insertions(+), 111 deletions(-)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 836aa480961c..5b1e0f81eebb 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -643,6 +643,7 @@ struct iommu_fwspec {
*/
struct iommu_sva {
struct device *dev;
+ struct iommu_domain *domain;
};

int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode,
@@ -684,11 +685,6 @@ void iommu_release_device(struct device *dev);
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);

-struct iommu_sva *iommu_sva_bind_device(struct device *dev,
- struct mm_struct *mm);
-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);

@@ -1029,21 +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)
-{
- 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;
@@ -1121,4 +1102,26 @@ void iommu_debugfs_setup(void);
static inline void iommu_debugfs_setup(void) {}
#endif

+#ifdef CONFIG_IOMMU_SVA
+struct iommu_sva *iommu_sva_bind_device(struct device *dev,
+ struct mm_struct *mm);
+void iommu_sva_unbind_device(struct iommu_sva *handle);
+u32 iommu_sva_get_pasid(struct iommu_sva *handle);
+#else
+static inline struct iommu_sva *
+iommu_sva_bind_device(struct device *dev, struct mm_struct *mm)
+{
+ 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 */
+
#endif /* __LINUX_IOMMU_H */
diff --git a/drivers/iommu/iommu-sva-lib.c b/drivers/iommu/iommu-sva-lib.c
index 106506143896..197f68602439 100644
--- a/drivers/iommu/iommu-sva-lib.c
+++ b/drivers/iommu/iommu-sva-lib.c
@@ -4,6 +4,7 @@
*/
#include <linux/mutex.h>
#include <linux/sched/mm.h>
+#include <linux/iommu.h>

#include "iommu-sva-lib.h"

@@ -69,3 +70,112 @@ 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_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
+ *
+ * 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)
+{
+ struct iommu_domain *domain;
+ struct iommu_sva *handle;
+ ioasid_t max_pasids;
+ int ret;
+
+ max_pasids = dev->iommu->max_pasids;
+ if (!max_pasids)
+ return ERR_PTR(-EOPNOTSUPP);
+
+ /* Allocate mm->pasid if necessary. */
+ ret = iommu_sva_alloc_pasid(mm, 1, max_pasids - 1);
+ if (ret)
+ return ERR_PTR(ret);
+
+ handle = kzalloc(sizeof(*handle), GFP_KERNEL);
+ if (!handle)
+ return ERR_PTR(-ENOMEM);
+
+ mutex_lock(&iommu_sva_lock);
+ /* Search for an existing domain. */
+ domain = iommu_get_domain_for_dev_pasid(dev, mm->pasid,
+ IOMMU_DOMAIN_SVA);
+ if (IS_ERR(domain)) {
+ ret = PTR_ERR(domain);
+ goto out_unlock;
+ }
+
+ if (domain) {
+ domain->users++;
+ goto out;
+ }
+
+ /* Allocate a new domain and set it on device pasid. */
+ domain = iommu_sva_domain_alloc(dev, mm);
+ if (!domain) {
+ ret = -ENOMEM;
+ goto out_unlock;
+ }
+
+ ret = iommu_attach_device_pasid(domain, dev, mm->pasid);
+ if (ret)
+ goto out_free_domain;
+ domain->users = 1;
+out:
+ mutex_unlock(&iommu_sva_lock);
+ handle->dev = dev;
+ handle->domain = domain;
+
+ return handle;
+
+out_free_domain:
+ iommu_domain_free(domain);
+out_unlock:
+ mutex_unlock(&iommu_sva_lock);
+ kfree(handle);
+
+ 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 iommu_domain *domain = handle->domain;
+ ioasid_t pasid = domain->mm->pasid;
+ struct device *dev = handle->dev;
+
+ mutex_lock(&iommu_sva_lock);
+ if (--domain->users == 0) {
+ iommu_detach_device_pasid(domain, dev, pasid);
+ iommu_domain_free(domain);
+ }
+ mutex_unlock(&iommu_sva_lock);
+ kfree(handle);
+}
+EXPORT_SYMBOL_GPL(iommu_sva_unbind_device);
+
+u32 iommu_sva_get_pasid(struct iommu_sva *handle)
+{
+ struct iommu_domain *domain = handle->domain;
+
+ return domain->mm->pasid;
+}
+EXPORT_SYMBOL_GPL(iommu_sva_get_pasid);
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 630e1b64ed89..1119fe39e842 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2785,97 +2785,6 @@ int iommu_dev_disable_feature(struct device *dev, enum iommu_dev_features feat)
}
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
- *
- * 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)
-{
- 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);
-
-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