Commit be51b1d6 authored by Lu Baolu's avatar Lu Baolu Committed by Joerg Roedel
Browse files

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: default avatarLu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: default avatarJean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Tested-by: default avatarZhangfei Gao <zhangfei.gao@linaro.org>
Tested-by: default avatarTony Zhu <tony.zhu@intel.com>
Link: https://lore.kernel.org/r/20221031005917.45690-10-baolu.lu@linux.intel.com


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 386fa64f

drivers/iommu/iommu-sva-lib.c

+111 −0
Original line number Diff line number Diff line
@@ -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);

drivers/iommu/iommu.c

+0 −91
Original line number Diff line number Diff line
@@ -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

 *

include/linux/iommu.h

+23 −20
Original line number Diff line number Diff line
@@ -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 */