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