From 7ba564722d98e3e7bc3922ad4f2885ca0336674e Mon Sep 17 00:00:00 2001 From: Fenghua Yu Date: Mon, 7 Feb 2022 15:02:44 -0800 Subject: iommu/sva: Rename CONFIG_IOMMU_SVA_LIB to CONFIG_IOMMU_SVA This CONFIG option originally only referred to the Shared Virtual Address (SVA) library. But it is now also used for non-library portions of code. Drop the "_LIB" suffix so that there is just one configuration option for all code relating to SVA. Signed-off-by: Fenghua Yu Signed-off-by: Borislav Petkov Reviewed-by: Tony Luck Reviewed-by: Thomas Gleixner Reviewed-by: Lu Baolu Link: https://lore.kernel.org/r/20220207230254.3342514-2-fenghua.yu@intel.com --- drivers/iommu/Kconfig | 6 +++--- drivers/iommu/Makefile | 2 +- drivers/iommu/intel/Kconfig | 2 +- drivers/iommu/iommu-sva-lib.h | 6 +++--- 4 files changed, 8 insertions(+), 8 deletions(-) (limited to 'drivers/iommu') diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig index 3eb68fa1b8cc..c79a0df090c0 100644 --- a/drivers/iommu/Kconfig +++ b/drivers/iommu/Kconfig @@ -144,8 +144,8 @@ config IOMMU_DMA select IRQ_MSI_IOMMU select NEED_SG_DMA_LENGTH -# Shared Virtual Addressing library -config IOMMU_SVA_LIB +# Shared Virtual Addressing +config IOMMU_SVA bool select IOASID @@ -379,7 +379,7 @@ config ARM_SMMU_V3 config ARM_SMMU_V3_SVA bool "Shared Virtual Addressing support for the ARM SMMUv3" depends on ARM_SMMU_V3 - select IOMMU_SVA_LIB + select IOMMU_SVA select MMU_NOTIFIER help Support for sharing process address spaces with devices using the diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile index bc7f730edbb0..44475a9b3eea 100644 --- a/drivers/iommu/Makefile +++ b/drivers/iommu/Makefile @@ -27,6 +27,6 @@ obj-$(CONFIG_FSL_PAMU) += fsl_pamu.o fsl_pamu_domain.o obj-$(CONFIG_S390_IOMMU) += s390-iommu.o obj-$(CONFIG_HYPERV_IOMMU) += hyperv-iommu.o obj-$(CONFIG_VIRTIO_IOMMU) += virtio-iommu.o -obj-$(CONFIG_IOMMU_SVA_LIB) += iommu-sva-lib.o io-pgfault.o +obj-$(CONFIG_IOMMU_SVA) += iommu-sva-lib.o io-pgfault.o obj-$(CONFIG_SPRD_IOMMU) += sprd-iommu.o obj-$(CONFIG_APPLE_DART) += apple-dart.o diff --git a/drivers/iommu/intel/Kconfig b/drivers/iommu/intel/Kconfig index 247d0f2d5fdf..39a06d245f12 100644 --- a/drivers/iommu/intel/Kconfig +++ b/drivers/iommu/intel/Kconfig @@ -52,7 +52,7 @@ config INTEL_IOMMU_SVM select PCI_PRI select MMU_NOTIFIER select IOASID - select IOMMU_SVA_LIB + select IOMMU_SVA help Shared Virtual Memory (SVM) provides a facility for devices to access DMA resources through process address space by diff --git a/drivers/iommu/iommu-sva-lib.h b/drivers/iommu/iommu-sva-lib.h index 031155010ca8..95dc3ebc1928 100644 --- a/drivers/iommu/iommu-sva-lib.h +++ b/drivers/iommu/iommu-sva-lib.h @@ -17,7 +17,7 @@ struct device; struct iommu_fault; struct iopf_queue; -#ifdef CONFIG_IOMMU_SVA_LIB +#ifdef CONFIG_IOMMU_SVA int iommu_queue_iopf(struct iommu_fault *fault, void *cookie); int iopf_queue_add_device(struct iopf_queue *queue, struct device *dev); @@ -28,7 +28,7 @@ struct iopf_queue *iopf_queue_alloc(const char *name); void iopf_queue_free(struct iopf_queue *queue); int iopf_queue_discard_partial(struct iopf_queue *queue); -#else /* CONFIG_IOMMU_SVA_LIB */ +#else /* CONFIG_IOMMU_SVA */ static inline int iommu_queue_iopf(struct iommu_fault *fault, void *cookie) { return -ENODEV; @@ -64,5 +64,5 @@ static inline int iopf_queue_discard_partial(struct iopf_queue *queue) { return -ENODEV; } -#endif /* CONFIG_IOMMU_SVA_LIB */ +#endif /* CONFIG_IOMMU_SVA */ #endif /* _IOMMU_SVA_LIB_H */ -- cgit v1.2.3 From 701fac40384f07197b106136012804c3cae0b3de Mon Sep 17 00:00:00 2001 From: Fenghua Yu Date: Mon, 7 Feb 2022 15:02:48 -0800 Subject: iommu/sva: Assign a PASID to mm on PASID allocation and free it on mm exit PASIDs are process-wide. It was attempted to use refcounted PASIDs to free them when the last thread drops the refcount. This turned out to be complex and error prone. Given the fact that the PASID space is 20 bits, which allows up to 1M processes to have a PASID associated concurrently, PASID resource exhaustion is not a realistic concern. Therefore, it was decided to simplify the approach and stick with lazy on demand PASID allocation, but drop the eager free approach and make an allocated PASID's lifetime bound to the lifetime of the process. Get rid of the refcounting mechanisms and replace/rename the interfaces to reflect this new approach. [ bp: Massage commit message. ] Suggested-by: Dave Hansen Signed-off-by: Fenghua Yu Signed-off-by: Borislav Petkov Reviewed-by: Tony Luck Reviewed-by: Lu Baolu Reviewed-by: Jacob Pan Reviewed-by: Thomas Gleixner Acked-by: Joerg Roedel Link: https://lore.kernel.org/r/20220207230254.3342514-6-fenghua.yu@intel.com --- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 5 +--- drivers/iommu/intel/iommu.c | 4 +-- drivers/iommu/intel/svm.c | 9 ------ drivers/iommu/ioasid.c | 39 +++---------------------- drivers/iommu/iommu-sva-lib.c | 39 ++++++++----------------- drivers/iommu/iommu-sva-lib.h | 1 - include/linux/ioasid.h | 12 ++------ include/linux/sched/mm.h | 16 ++++++++++ kernel/fork.c | 1 + 9 files changed, 38 insertions(+), 88 deletions(-) (limited to 'drivers/iommu') diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c index a737ba5f727e..22ddd05bbdcd 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c @@ -340,14 +340,12 @@ __arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm) bond->smmu_mn = arm_smmu_mmu_notifier_get(smmu_domain, mm); if (IS_ERR(bond->smmu_mn)) { ret = PTR_ERR(bond->smmu_mn); - goto err_free_pasid; + goto err_free_bond; } list_add(&bond->list, &master->bonds); return &bond->sva; -err_free_pasid: - iommu_sva_free_pasid(mm); err_free_bond: kfree(bond); return ERR_PTR(ret); @@ -377,7 +375,6 @@ void arm_smmu_sva_unbind(struct iommu_sva *handle) if (refcount_dec_and_test(&bond->refs)) { list_del(&bond->list); arm_smmu_mmu_notifier_put(bond->smmu_mn); - iommu_sva_free_pasid(bond->mm); kfree(bond); } mutex_unlock(&sva_lock); diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 92fea3fbbb11..ef03b2176bbd 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -4781,7 +4781,7 @@ attach_failed: link_failed: spin_unlock_irqrestore(&device_domain_lock, flags); if (list_empty(&domain->subdevices) && domain->default_pasid > 0) - ioasid_put(domain->default_pasid); + ioasid_free(domain->default_pasid); return ret; } @@ -4811,7 +4811,7 @@ static void aux_domain_remove_dev(struct dmar_domain *domain, spin_unlock_irqrestore(&device_domain_lock, flags); if (list_empty(&domain->subdevices) && domain->default_pasid > 0) - ioasid_put(domain->default_pasid); + ioasid_free(domain->default_pasid); } static int prepare_domain_attach_device(struct iommu_domain *domain, diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c index 5b5d69b04fcc..51ac2096b3da 100644 --- a/drivers/iommu/intel/svm.c +++ b/drivers/iommu/intel/svm.c @@ -514,11 +514,6 @@ static int intel_svm_alloc_pasid(struct device *dev, struct mm_struct *mm, return iommu_sva_alloc_pasid(mm, PASID_MIN, max_pasid - 1); } -static void intel_svm_free_pasid(struct mm_struct *mm) -{ - iommu_sva_free_pasid(mm); -} - static struct iommu_sva *intel_svm_bind_mm(struct intel_iommu *iommu, struct device *dev, struct mm_struct *mm, @@ -662,8 +657,6 @@ static int intel_svm_unbind_mm(struct device *dev, u32 pasid) kfree(svm); } } - /* Drop a PASID reference and free it if no reference. */ - intel_svm_free_pasid(mm); } out: return ret; @@ -1047,8 +1040,6 @@ struct iommu_sva *intel_svm_bind(struct device *dev, struct mm_struct *mm, void } sva = intel_svm_bind_mm(iommu, dev, mm, flags); - if (IS_ERR_OR_NULL(sva)) - intel_svm_free_pasid(mm); mutex_unlock(&pasid_mutex); return sva; diff --git a/drivers/iommu/ioasid.c b/drivers/iommu/ioasid.c index 06fee7416816..a786c034907c 100644 --- a/drivers/iommu/ioasid.c +++ b/drivers/iommu/ioasid.c @@ -2,7 +2,7 @@ /* * I/O Address Space ID allocator. There is one global IOASID space, split into * subsets. Users create a subset with DECLARE_IOASID_SET, then allocate and - * free IOASIDs with ioasid_alloc and ioasid_put. + * free IOASIDs with ioasid_alloc() and ioasid_free(). */ #include #include @@ -15,7 +15,6 @@ struct ioasid_data { struct ioasid_set *set; void *private; struct rcu_head rcu; - refcount_t refs; }; /* @@ -315,7 +314,6 @@ ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max, data->set = set; data->private = private; - refcount_set(&data->refs, 1); /* * Custom allocator needs allocator data to perform platform specific @@ -348,35 +346,11 @@ exit_free: EXPORT_SYMBOL_GPL(ioasid_alloc); /** - * ioasid_get - obtain a reference to the IOASID - * @ioasid: the ID to get - */ -void ioasid_get(ioasid_t ioasid) -{ - struct ioasid_data *ioasid_data; - - spin_lock(&ioasid_allocator_lock); - ioasid_data = xa_load(&active_allocator->xa, ioasid); - if (ioasid_data) - refcount_inc(&ioasid_data->refs); - else - WARN_ON(1); - spin_unlock(&ioasid_allocator_lock); -} -EXPORT_SYMBOL_GPL(ioasid_get); - -/** - * ioasid_put - Release a reference to an ioasid + * ioasid_free - Free an ioasid * @ioasid: the ID to remove - * - * Put a reference to the IOASID, free it when the number of references drops to - * zero. - * - * Return: %true if the IOASID was freed, %false otherwise. */ -bool ioasid_put(ioasid_t ioasid) +void ioasid_free(ioasid_t ioasid) { - bool free = false; struct ioasid_data *ioasid_data; spin_lock(&ioasid_allocator_lock); @@ -386,10 +360,6 @@ bool ioasid_put(ioasid_t ioasid) goto exit_unlock; } - free = refcount_dec_and_test(&ioasid_data->refs); - if (!free) - goto exit_unlock; - active_allocator->ops->free(ioasid, active_allocator->ops->pdata); /* Custom allocator needs additional steps to free the xa element */ if (active_allocator->flags & IOASID_ALLOCATOR_CUSTOM) { @@ -399,9 +369,8 @@ bool ioasid_put(ioasid_t ioasid) exit_unlock: spin_unlock(&ioasid_allocator_lock); - return free; } -EXPORT_SYMBOL_GPL(ioasid_put); +EXPORT_SYMBOL_GPL(ioasid_free); /** * ioasid_find - Find IOASID data diff --git a/drivers/iommu/iommu-sva-lib.c b/drivers/iommu/iommu-sva-lib.c index bd41405d34e9..106506143896 100644 --- a/drivers/iommu/iommu-sva-lib.c +++ b/drivers/iommu/iommu-sva-lib.c @@ -18,8 +18,7 @@ static DECLARE_IOASID_SET(iommu_sva_pasid); * * 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. + * available in mm->pasid and will be available for the lifetime of the mm. * * Returns 0 on success and < 0 on error. */ @@ -33,38 +32,24 @@ int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max) return -EINVAL; mutex_lock(&iommu_sva_lock); - if (mm->pasid) { - if (mm->pasid >= min && mm->pasid <= max) - ioasid_get(mm->pasid); - else + /* Is a PASID already associated with this mm? */ + if (pasid_valid(mm->pasid)) { + if (mm->pasid < min || mm->pasid >= max) ret = -EOVERFLOW; - } else { - pasid = ioasid_alloc(&iommu_sva_pasid, min, max, mm); - if (pasid == INVALID_IOASID) - ret = -ENOMEM; - else - mm->pasid = pasid; + 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); -/** - * 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) { diff --git a/drivers/iommu/iommu-sva-lib.h b/drivers/iommu/iommu-sva-lib.h index 95dc3ebc1928..8909ea1094e3 100644 --- a/drivers/iommu/iommu-sva-lib.h +++ b/drivers/iommu/iommu-sva-lib.h @@ -9,7 +9,6 @@ #include int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max); -void iommu_sva_free_pasid(struct mm_struct *mm); struct mm_struct *iommu_sva_find(ioasid_t pasid); /* I/O Page fault */ diff --git a/include/linux/ioasid.h b/include/linux/ioasid.h index 2237f64dbaae..af1c9d62e642 100644 --- a/include/linux/ioasid.h +++ b/include/linux/ioasid.h @@ -34,8 +34,7 @@ struct ioasid_allocator_ops { #if IS_ENABLED(CONFIG_IOASID) ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max, void *private); -void ioasid_get(ioasid_t ioasid); -bool ioasid_put(ioasid_t ioasid); +void ioasid_free(ioasid_t ioasid); void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid, bool (*getter)(void *)); int ioasid_register_allocator(struct ioasid_allocator_ops *allocator); @@ -53,14 +52,7 @@ static inline ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, return INVALID_IOASID; } -static inline void ioasid_get(ioasid_t ioasid) -{ -} - -static inline bool ioasid_put(ioasid_t ioasid) -{ - return false; -} +static inline void ioasid_free(ioasid_t ioasid) { } static inline void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid, bool (*getter)(void *)) diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index c74d1edbac2f..a80356e9dc69 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -439,8 +439,24 @@ static inline void mm_pasid_init(struct mm_struct *mm) { mm->pasid = INVALID_IOASID; } + +/* Associate a PASID with an mm_struct: */ +static inline void mm_pasid_set(struct mm_struct *mm, u32 pasid) +{ + mm->pasid = pasid; +} + +static inline void mm_pasid_drop(struct mm_struct *mm) +{ + if (pasid_valid(mm->pasid)) { + ioasid_free(mm->pasid); + mm->pasid = INVALID_IOASID; + } +} #else static inline void mm_pasid_init(struct mm_struct *mm) {} +static inline void mm_pasid_set(struct mm_struct *mm, u32 pasid) {} +static inline void mm_pasid_drop(struct mm_struct *mm) {} #endif #endif /* _LINUX_SCHED_MM_H */ diff --git a/kernel/fork.c b/kernel/fork.c index deacd2c17a7f..c03c6682464c 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1115,6 +1115,7 @@ static inline void __mmput(struct mm_struct *mm) } if (mm->binfmt) module_put(mm->binfmt->module); + mm_pasid_drop(mm); mmdrop(mm); } -- cgit v1.2.3