87 lines
2.2 KiB
C
87 lines
2.2 KiB
C
|
// SPDX-License-Identifier: GPL-2.0
|
||
|
/*
|
||
|
* Helpers for IOMMU drivers implementing SVA
|
||
|
*/
|
||
|
#include <linux/mutex.h>
|
||
|
#include <linux/sched/mm.h>
|
||
|
|
||
|
#include "iommu-sva-lib.h"
|
||
|
|
||
|
static DEFINE_MUTEX(iommu_sva_lock);
|
||
|
static DECLARE_IOASID_SET(iommu_sva_pasid);
|
||
|
|
||
|
/**
|
||
|
* iommu_sva_alloc_pasid - Allocate a PASID for the mm
|
||
|
* @mm: the mm
|
||
|
* @min: minimum PASID value (inclusive)
|
||
|
* @max: maximum PASID value (inclusive)
|
||
|
*
|
||
|
* Try to allocate a PASID for this mm, or take a reference to the existing one
|
||
|
* provided it fits within the [@min, @max] range. On success the PASID is
|
||
|
* available in mm->pasid, and must be released with iommu_sva_free_pasid().
|
||
|
* @min must be greater than 0, because 0 indicates an unused mm->pasid.
|
||
|
*
|
||
|
* Returns 0 on success and < 0 on error.
|
||
|
*/
|
||
|
int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max)
|
||
|
{
|
||
|
int ret = 0;
|
||
|
ioasid_t pasid;
|
||
|
|
||
|
if (min == INVALID_IOASID || max == INVALID_IOASID ||
|
||
|
min == 0 || max < min)
|
||
|
return -EINVAL;
|
||
|
|
||
|
mutex_lock(&iommu_sva_lock);
|
||
|
if (mm->pasid) {
|
||
|
if (mm->pasid >= min && mm->pasid <= max)
|
||
|
ioasid_get(mm->pasid);
|
||
|
else
|
||
|
ret = -EOVERFLOW;
|
||
|
} else {
|
||
|
pasid = ioasid_alloc(&iommu_sva_pasid, min, max, mm);
|
||
|
if (pasid == INVALID_IOASID)
|
||
|
ret = -ENOMEM;
|
||
|
else
|
||
|
mm->pasid = pasid;
|
||
|
}
|
||
|
mutex_unlock(&iommu_sva_lock);
|
||
|
return ret;
|
||
|
}
|
||
|
EXPORT_SYMBOL_GPL(iommu_sva_alloc_pasid);
|
||
|
|
||
|
/**
|
||
|
* iommu_sva_free_pasid - Release the mm's PASID
|
||
|
* @mm: the mm
|
||
|
*
|
||
|
* Drop one reference to a PASID allocated with iommu_sva_alloc_pasid()
|
||
|
*/
|
||
|
void iommu_sva_free_pasid(struct mm_struct *mm)
|
||
|
{
|
||
|
mutex_lock(&iommu_sva_lock);
|
||
|
if (ioasid_put(mm->pasid))
|
||
|
mm->pasid = 0;
|
||
|
mutex_unlock(&iommu_sva_lock);
|
||
|
}
|
||
|
EXPORT_SYMBOL_GPL(iommu_sva_free_pasid);
|
||
|
|
||
|
/* ioasid_find getter() requires a void * argument */
|
||
|
static bool __mmget_not_zero(void *mm)
|
||
|
{
|
||
|
return mmget_not_zero(mm);
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* iommu_sva_find() - Find mm associated to the given PASID
|
||
|
* @pasid: Process Address Space ID assigned to the mm
|
||
|
*
|
||
|
* On success a reference to the mm is taken, and must be released with mmput().
|
||
|
*
|
||
|
* Returns the mm corresponding to this PASID, or an error if not found.
|
||
|
*/
|
||
|
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);
|