[PATCH v4 2/9] iommu: Replace sva_iommu with iommu_attach_handle

Lu Baolu
2024-04-03T01:16:30Z

The struct sva_iommu represents a bond of an SVA domain and a device.
It is functionally equivalent to the iommu_attach_handle. To avoid
code duplication, replace sva_iommu with the iommu_attach_handle and
remove the code that manages sva_iommu.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
include/linux/iommu.h | 28 +++++------------
include/linux/uacce.h | 2 +-
drivers/dma/idxd/idxd.h | 2 +-
drivers/dma/idxd/cdev.c | 4 +--
drivers/iommu/iommu-sva.c | 61 ++++++++++++++++----------------------
drivers/misc/uacce/uacce.c | 2 +-
6 files changed, 38 insertions(+), 61 deletions(-)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 2e925b5eba53..be9c9a10169d 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -39,7 +39,6 @@ struct iommu_domain;
struct iommu_domain_ops;
struct iommu_dirty_ops;
struct notifier_block;
-struct iommu_sva;
struct iommu_dma_cookie;
struct iommu_fault_param;

@@ -986,20 +985,9 @@ struct iommu_fwspec {
/* ATS is supported */
#define IOMMU_FWSPEC_PCI_RC_ATS (1 << 0)

-/**
- * struct iommu_sva - handle to a device-mm bond
- */
-struct iommu_sva {
- struct device *dev;
- struct iommu_domain *domain;
- struct list_head handle_item;
- refcount_t users;
-};
-
struct iommu_mm_data {
u32 pasid;
struct list_head sva_domains;
- struct list_head sva_handles;
};

int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode,
@@ -1527,24 +1515,24 @@ static inline u32 mm_get_enqcmd_pasid(struct mm_struct *mm)
}

void mm_pasid_drop(struct mm_struct *mm);
-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);
+struct iommu_attach_handle *iommu_sva_bind_device(struct device *dev,
+ struct mm_struct *mm);
+void iommu_sva_unbind_device(struct iommu_attach_handle *handle);
+u32 iommu_sva_get_pasid(struct iommu_attach_handle *handle);
struct iommu_domain *iommu_sva_domain_alloc(struct device *dev,
struct mm_struct *mm);
#else
-static inline struct iommu_sva *
+static inline struct iommu_attach_handle *
iommu_sva_bind_device(struct device *dev, struct mm_struct *mm)
{
- return NULL;
+ return ERR_PTR(-ENODEV);
}

-static inline void iommu_sva_unbind_device(struct iommu_sva *handle)
+static inline void iommu_sva_unbind_device(struct iommu_attach_handle *handle)
{
}

-static inline u32 iommu_sva_get_pasid(struct iommu_sva *handle)
+static inline u32 iommu_sva_get_pasid(struct iommu_attach_handle *handle)
{
return IOMMU_PASID_INVALID;
}
diff --git a/include/linux/uacce.h b/include/linux/uacce.h
index e290c0269944..1548119c89ae 100644
--- a/include/linux/uacce.h
+++ b/include/linux/uacce.h
@@ -97,7 +97,7 @@ struct uacce_queue {
struct mutex mutex;
enum uacce_q_state state;
u32 pasid;
- struct iommu_sva *handle;
+ struct iommu_attach_handle *handle;
struct address_space *mapping;
};

diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index a4099a1e2340..3ee89e9cb049 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -335,7 +335,7 @@ struct idxd_device {
struct idxd_wq **wqs;
struct idxd_engine **engines;

- struct iommu_sva *sva;
+ struct iommu_attach_handle *sva;
unsigned int pasid;

int num_groups;
diff --git a/drivers/dma/idxd/cdev.c b/drivers/dma/idxd/cdev.c
index 8078ab9acfbc..a029bda92615 100644
--- a/drivers/dma/idxd/cdev.c
+++ b/drivers/dma/idxd/cdev.c
@@ -45,7 +45,7 @@ struct idxd_user_context {
unsigned int pasid;
struct mm_struct *mm;
unsigned int flags;
- struct iommu_sva *sva;
+ struct iommu_attach_handle *sva;
struct idxd_dev idxd_dev;
u64 counters[COUNTER_MAX];
int id;
@@ -225,7 +225,7 @@ static int idxd_cdev_open(struct inode *inode, struct file *filp)
struct idxd_wq *wq;
struct device *dev, *fdev;
int rc = 0;
- struct iommu_sva *sva;
+ struct iommu_attach_handle *sva;
unsigned int pasid;
struct idxd_cdev *idxd_cdev;

diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c
index 640acc804e8c..35ac2e4836e9 100644
--- a/drivers/iommu/iommu-sva.c
+++ b/drivers/iommu/iommu-sva.c
@@ -41,7 +41,6 @@ static struct iommu_mm_data *iommu_alloc_mm_data(struct mm_struct *mm, struct de
}
iommu_mm->pasid = pasid;
INIT_LIST_HEAD(&iommu_mm->sva_domains);
- INIT_LIST_HEAD(&iommu_mm->sva_handles);
/*
* Make sure the write to mm->iommu_mm is not reordered in front of
* initialization to iommu_mm fields. If it does, readers may see a
@@ -67,13 +66,17 @@ static struct iommu_mm_data *iommu_alloc_mm_data(struct mm_struct *mm, struct de
*
* On error, returns an ERR_PTR value.
*/
-struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm)
+struct iommu_attach_handle *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm)
{
+ struct iommu_group *group = dev->iommu_group;
+ struct iommu_attach_handle *handle;
struct iommu_mm_data *iommu_mm;
struct iommu_domain *domain;
- struct iommu_sva *handle;
int ret;

+ if (!group)
+ return ERR_PTR(-ENODEV);
+
mutex_lock(&iommu_sva_lock);

/* Allocate mm->pasid if necessary. */
@@ -83,18 +86,11 @@ struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm
goto out_unlock;
}

- list_for_each_entry(handle, &mm->iommu_mm->sva_handles, handle_item) {
- if (handle->dev == dev) {
- refcount_inc(&handle->users);
- mutex_unlock(&iommu_sva_lock);
- return handle;
- }
- }
-
- handle = kzalloc(sizeof(*handle), GFP_KERNEL);
- if (!handle) {
- ret = -ENOMEM;
- goto out_unlock;
+ /* A bond already exists, just take a reference`. */
+ handle = iommu_attach_handle_get(group, iommu_mm->pasid);
+ if (handle) {
+ mutex_unlock(&iommu_sva_lock);
+ return handle;
}

/* Search for an existing domain. */
@@ -110,7 +106,7 @@ struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm
domain = iommu_sva_domain_alloc(dev, mm);
if (!domain) {
ret = -ENOMEM;
- goto out_free_handle;
+ goto out_unlock;
}

ret = iommu_attach_device_pasid(domain, dev, iommu_mm->pasid);
@@ -120,17 +116,14 @@ struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm
list_add(&domain->next, &mm->iommu_mm->sva_domains);

out:
- refcount_set(&handle->users, 1);
- list_add(&handle->handle_item, &mm->iommu_mm->sva_handles);
+ handle = iommu_attach_handle_get(group, iommu_mm->pasid);
mutex_unlock(&iommu_sva_lock);
- handle->dev = dev;
- handle->domain = domain;
+ handle->priv = dev;
+
return handle;

out_free_domain:
iommu_domain_free(domain);
-out_free_handle:
- kfree(handle);
out_unlock:
mutex_unlock(&iommu_sva_lock);
return ERR_PTR(ret);
@@ -145,30 +138,26 @@ EXPORT_SYMBOL_GPL(iommu_sva_bind_device);
* 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)
+void iommu_sva_unbind_device(struct iommu_attach_handle *handle)
{
struct iommu_domain *domain = handle->domain;
struct iommu_mm_data *iommu_mm = domain->mm->iommu_mm;
- struct device *dev = handle->dev;
+ struct device *dev = handle->priv;

mutex_lock(&iommu_sva_lock);
- if (!refcount_dec_and_test(&handle->users)) {
- mutex_unlock(&iommu_sva_lock);
- return;
- }
- list_del(&handle->handle_item);
-
- iommu_detach_device_pasid(domain, dev, iommu_mm->pasid);
- if (--domain->users == 0) {
- list_del(&domain->next);
- iommu_domain_free(domain);
+ iommu_attach_handle_put(handle);
+ if (refcount_read(&handle->users) == 1) {
+ iommu_detach_device_pasid(domain, dev, iommu_mm->pasid);
+ if (--domain->users == 0) {
+ list_del(&domain->next);
+ 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)
+u32 iommu_sva_get_pasid(struct iommu_attach_handle *handle)
{
struct iommu_domain *domain = handle->domain;

diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c
index bdc2e6fda782..b325097421c1 100644
--- a/drivers/misc/uacce/uacce.c
+++ b/drivers/misc/uacce/uacce.c
@@ -106,7 +106,7 @@ static long uacce_fops_compat_ioctl(struct file *filep,
static int uacce_bind_queue(struct uacce_device *uacce, struct uacce_queue *q)
{
u32 pasid;
- struct iommu_sva *handle;
+ struct iommu_attach_handle *handle;

if (!(uacce->flags & UACCE_DEV_SVA))
return 0;
--
2.34.1