// 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 will be available for the lifetime of the mm. * * 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); /* Is a PASID already associated with this mm? */ if (pasid_valid(mm->pasid)) { if (mm->pasid < min || mm->pasid >= max) ret = -EOVERFLOW; goto out; } pasid = ioasid_alloc(&iommu_sva_pasid, min, max, mm); if (!pasid_valid(pasid)) ret = -ENOMEM; else mm_pasid_set(mm, pasid); out: mutex_unlock(&iommu_sva_lock); return ret; } EXPORT_SYMBOL_GPL(iommu_sva_alloc_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);