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iommu/sva: Refactoring iommu_sva_bind/unbind_device() 

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_attach/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>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Tested-by: Tony Zhu <tony.zhu@intel.com>
Link: https://lore.kernel.org/r/20221031005917.45690-10-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Lu Baolu 2022-10-31 08:59:13 +08:00 committed by Joerg Roedel
parent 386fa64fd5
commit be51b1d6bb
3 changed files with 134 additions and 111 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

111
drivers/iommu/iommu-sva-lib.c
View File

@ -4,6 +4,7 @@
*/
#include <linux/mutex.h>
#include <linux/sched/mm.h>
#include <linux/iommu.h>
#include "iommu-sva-lib.h"
@ -69,3 +70,113 @@ 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 PASID returned by iommu_sva_get_pasid(). If a
* bond already exists between @device and @mm, an additional internal
* 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);

91
drivers/iommu/iommu.c
View File

@ -2751,97 +2751,6 @@ 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
*

43
include/linux/iommu.h
View File

@ -645,6 +645,7 @@ 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,
@ -686,11 +687,6 @@ 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);
@ -1026,21 +1022,6 @@ 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;
@ -1154,4 +1135,26 @@ static inline void iommu_dma_compose_msi_msg(struct msi_desc *desc, struct msi_m
#endif /* CONFIG_IOMMU_DMA */
#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 */