diff options
| -rw-r--r-- | drivers/iommu/Kconfig | 7 | ||||
| -rw-r--r-- | drivers/iommu/Makefile | 1 | ||||
| -rw-r--r-- | drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 244 | ||||
| -rw-r--r-- | drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 50 | ||||
| -rw-r--r-- | drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 30 | ||||
| -rw-r--r-- | drivers/iommu/intel/iommu.c | 4 | ||||
| -rw-r--r-- | drivers/iommu/intel/svm.c | 6 | ||||
| -rw-r--r-- | drivers/iommu/ioasid.c | 38 | ||||
| -rw-r--r-- | drivers/iommu/iommu-sva-lib.c | 86 | ||||
| -rw-r--r-- | drivers/iommu/iommu-sva-lib.h | 15 | ||||
| -rw-r--r-- | include/linux/ioasid.h | 10 |
11 files changed, 468 insertions, 23 deletions
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig index 04878caf6da4..192ef8f61310 100644 --- a/drivers/iommu/Kconfig +++ b/drivers/iommu/Kconfig @@ -103,6 +103,11 @@ config IOMMU_DMA select IRQ_MSI_IOMMU select NEED_SG_DMA_LENGTH +# Shared Virtual Addressing library +config IOMMU_SVA_LIB + bool + select IOASID + config FSL_PAMU bool "Freescale IOMMU support" depends on PCI @@ -311,6 +316,8 @@ 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 MMU_NOTIFIER help Support for sharing process address spaces with devices using the SMMUv3. diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile index 11f1771104f3..61bd30cd8369 100644 --- a/drivers/iommu/Makefile +++ b/drivers/iommu/Makefile @@ -27,3 +27,4 @@ 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 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 9255c9600fb8..e13b092e6004 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 @@ -5,11 +5,35 @@ #include <linux/mm.h> #include <linux/mmu_context.h> +#include <linux/mmu_notifier.h> #include <linux/slab.h> #include "arm-smmu-v3.h" +#include "../../iommu-sva-lib.h" #include "../../io-pgtable-arm.h" +struct arm_smmu_mmu_notifier { + struct mmu_notifier mn; + struct arm_smmu_ctx_desc *cd; + bool cleared; + refcount_t refs; + struct list_head list; + struct arm_smmu_domain *domain; +}; + +#define mn_to_smmu(mn) container_of(mn, struct arm_smmu_mmu_notifier, mn) + +struct arm_smmu_bond { + struct iommu_sva sva; + struct mm_struct *mm; + struct arm_smmu_mmu_notifier *smmu_mn; + struct list_head list; + refcount_t refs; +}; + +#define sva_to_bond(handle) \ + container_of(handle, struct arm_smmu_bond, sva) + static DEFINE_MUTEX(sva_lock); /* @@ -64,7 +88,6 @@ arm_smmu_share_asid(struct mm_struct *mm, u16 asid) return NULL; } -__maybe_unused static struct arm_smmu_ctx_desc *arm_smmu_alloc_shared_cd(struct mm_struct *mm) { u16 asid; @@ -145,7 +168,6 @@ out_put_context: return err < 0 ? ERR_PTR(err) : ret; } -__maybe_unused static void arm_smmu_free_shared_cd(struct arm_smmu_ctx_desc *cd) { if (arm_smmu_free_asid(cd)) { @@ -155,6 +177,215 @@ static void arm_smmu_free_shared_cd(struct arm_smmu_ctx_desc *cd) } } +static void arm_smmu_mm_invalidate_range(struct mmu_notifier *mn, + struct mm_struct *mm, + unsigned long start, unsigned long end) +{ + struct arm_smmu_mmu_notifier *smmu_mn = mn_to_smmu(mn); + + arm_smmu_atc_inv_domain(smmu_mn->domain, mm->pasid, start, + end - start + 1); +} + +static void arm_smmu_mm_release(struct mmu_notifier *mn, struct mm_struct *mm) +{ + struct arm_smmu_mmu_notifier *smmu_mn = mn_to_smmu(mn); + struct arm_smmu_domain *smmu_domain = smmu_mn->domain; + + mutex_lock(&sva_lock); + if (smmu_mn->cleared) { + mutex_unlock(&sva_lock); + return; + } + + /* + * DMA may still be running. Keep the cd valid to avoid C_BAD_CD events, + * but disable translation. + */ + arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, &quiet_cd); + + arm_smmu_tlb_inv_asid(smmu_domain->smmu, smmu_mn->cd->asid); + arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, 0, 0); + + smmu_mn->cleared = true; + mutex_unlock(&sva_lock); +} + +static void arm_smmu_mmu_notifier_free(struct mmu_notifier *mn) +{ + kfree(mn_to_smmu(mn)); +} + +static struct mmu_notifier_ops arm_smmu_mmu_notifier_ops = { + .invalidate_range = arm_smmu_mm_invalidate_range, + .release = arm_smmu_mm_release, + .free_notifier = arm_smmu_mmu_notifier_free, +}; + +/* Allocate or get existing MMU notifier for this {domain, mm} pair */ +static struct arm_smmu_mmu_notifier * +arm_smmu_mmu_notifier_get(struct arm_smmu_domain *smmu_domain, + struct mm_struct *mm) +{ + int ret; + struct arm_smmu_ctx_desc *cd; + struct arm_smmu_mmu_notifier *smmu_mn; + + list_for_each_entry(smmu_mn, &smmu_domain->mmu_notifiers, list) { + if (smmu_mn->mn.mm == mm) { + refcount_inc(&smmu_mn->refs); + return smmu_mn; + } + } + + cd = arm_smmu_alloc_shared_cd(mm); + if (IS_ERR(cd)) + return ERR_CAST(cd); + + smmu_mn = kzalloc(sizeof(*smmu_mn), GFP_KERNEL); + if (!smmu_mn) { + ret = -ENOMEM; + goto err_free_cd; + } + + refcount_set(&smmu_mn->refs, 1); + smmu_mn->cd = cd; + smmu_mn->domain = smmu_domain; + smmu_mn->mn.ops = &arm_smmu_mmu_notifier_ops; + + ret = mmu_notifier_register(&smmu_mn->mn, mm); + if (ret) { + kfree(smmu_mn); + goto err_free_cd; + } + + ret = arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, cd); + if (ret) + goto err_put_notifier; + + list_add(&smmu_mn->list, &smmu_domain->mmu_notifiers); + return smmu_mn; + +err_put_notifier: + /* Frees smmu_mn */ + mmu_notifier_put(&smmu_mn->mn); +err_free_cd: + arm_smmu_free_shared_cd(cd); + return ERR_PTR(ret); +} + +static void arm_smmu_mmu_notifier_put(struct arm_smmu_mmu_notifier *smmu_mn) +{ + struct mm_struct *mm = smmu_mn->mn.mm; + struct arm_smmu_ctx_desc *cd = smmu_mn->cd; + struct arm_smmu_domain *smmu_domain = smmu_mn->domain; + + if (!refcount_dec_and_test(&smmu_mn->refs)) + return; + + list_del(&smmu_mn->list); + arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, NULL); + + /* + * If we went through clear(), we've already invalidated, and no + * new TLB entry can have been formed. + */ + if (!smmu_mn->cleared) { + arm_smmu_tlb_inv_asid(smmu_domain->smmu, cd->asid); + arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, 0, 0); + } + + /* Frees smmu_mn */ + mmu_notifier_put(&smmu_mn->mn); + arm_smmu_free_shared_cd(cd); +} + +static struct iommu_sva * +__arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm) +{ + int ret; + struct arm_smmu_bond *bond; + struct arm_smmu_master *master = dev_iommu_priv_get(dev); + struct iommu_domain *domain = iommu_get_domain_for_dev(dev); + struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain); + + if (!master || !master->sva_enabled) + return ERR_PTR(-ENODEV); + + /* If bind() was already called for this {dev, mm} pair, reuse it. */ + list_for_each_entry(bond, &master->bonds, list) { + if (bond->mm == mm) { + refcount_inc(&bond->refs); + return &bond->sva; + } + } + + bond = kzalloc(sizeof(*bond), GFP_KERNEL); + if (!bond) + return ERR_PTR(-ENOMEM); + + /* Allocate a PASID for this mm if necessary */ + ret = iommu_sva_alloc_pasid(mm, 1, (1U << master->ssid_bits) - 1); + if (ret) + goto err_free_bond; + + bond->mm = mm; + bond->sva.dev = dev; + refcount_set(&bond->refs, 1); + + 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; + } + + 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); +} + +struct iommu_sva * +arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm, void *drvdata) +{ + struct iommu_sva *handle; + struct iommu_domain *domain = iommu_get_domain_for_dev(dev); + struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain); + + if (smmu_domain->stage != ARM_SMMU_DOMAIN_S1) + return ERR_PTR(-EINVAL); + + mutex_lock(&sva_lock); + handle = __arm_smmu_sva_bind(dev, mm); + mutex_unlock(&sva_lock); + return handle; +} + +void arm_smmu_sva_unbind(struct iommu_sva *handle) +{ + struct arm_smmu_bond *bond = sva_to_bond(handle); + + mutex_lock(&sva_lock); + 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); +} + +u32 arm_smmu_sva_get_pasid(struct iommu_sva *handle) +{ + struct arm_smmu_bond *bond = sva_to_bond(handle); + + return bond->mm->pasid; +} + bool arm_smmu_sva_supported(struct arm_smmu_device *smmu) { unsigned long reg, fld; @@ -246,3 +477,12 @@ int arm_smmu_master_disable_sva(struct arm_smmu_master *master) return 0; } + +void arm_smmu_sva_notifier_synchronize(void) +{ + /* + * Some MMU notifiers may still be waiting to be freed, using + * arm_smmu_mmu_notifier_free(). Wait for them. + */ + mmu_notifier_synchronize(); +} diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c index c9cafce51835..2ddf5ecc75f8 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c @@ -76,6 +76,12 @@ struct arm_smmu_option_prop { DEFINE_XARRAY_ALLOC1(arm_smmu_asid_xa); DEFINE_MUTEX(arm_smmu_asid_lock); +/* + * Special value used by SVA when a process dies, to quiesce a CD without + * disabling it. + */ +struct arm_smmu_ctx_desc quiet_cd = { 0 }; + static struct arm_smmu_option_prop arm_smmu_options[] = { { ARM_SMMU_OPT_SKIP_PREFETCH, "hisilicon,broken-prefetch-cmd" }, { ARM_SMMU_OPT_PAGE0_REGS_ONLY, "cavium,cn9900-broken-page1-regspace"}, @@ -91,11 +97,6 @@ static inline void __iomem *arm_smmu_page1_fixup(unsigned long offset, return smmu->base + offset; } -static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom) -{ - return container_of(dom, struct arm_smmu_domain, domain); -} - static void parse_driver_options(struct arm_smmu_device *smmu) { int i = 0; @@ -983,7 +984,9 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid, * (2) Install a secondary CD, for SID+SSID traffic. * (3) Update ASID of a CD. Atomically write the first 64 bits of the * CD, then invalidate the old entry and mappings. - * (4) Remove a secondary CD. + * (4) Quiesce the context without clearing the valid bit. Disable + * translation, and ignore any translation fault. + * (5) Remove a secondary CD. */ u64 val; bool cd_live; @@ -1000,8 +1003,10 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid, val = le64_to_cpu(cdptr[0]); cd_live = !!(val & CTXDESC_CD_0_V); - if (!cd) { /* (4) */ + if (!cd) { /* (5) */ val = 0; + } else if (cd == &quiet_cd) { /* (4) */ + val |= CTXDESC_CD_0_TCR_EPD0; } else if (cd_live) { /* (3) */ val &= ~CTXDESC_CD_0_ASID; val |= FIELD_PREP(CTXDESC_CD_0_ASID, cd->asid); @@ -1519,6 +1524,20 @@ arm_smmu_atc_inv_to_cmd(int ssid, unsigned long iova, size_t size, size_t inval_grain_shift = 12; unsigned long page_start, page_end; + /* + * ATS and PASID: + * + * If substream_valid is clear, the PCIe TLP is sent without a PASID + * prefix. In that case all ATC entries within the address range are + * invalidated, including those that were requested with a PASID! There + * is no way to invalidate only entries without PASID. + * + * When using STRTAB_STE_1_S1DSS_SSID0 (reserving CD 0 for non-PASID + * traffic), translation requests without PASID create ATC entries + * without PASID, which must be invalidated with substream_valid clear. + * This has the unpleasant side-effect of invalidating all PASID-tagged + * ATC entries within the address range. + */ *cmd = (struct arm_smmu_cmdq_ent) { .opcode = CMDQ_OP_ATC_INV, .substream_valid = !!ssid, @@ -1577,8 +1596,8 @@ static int arm_smmu_atc_inv_master(struct arm_smmu_master *master) return arm_smmu_cmdq_issue_sync(master->smmu); } -static int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain, - int ssid, unsigned long iova, size_t size) +int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain, int ssid, + unsigned long iova, size_t size) { int i; unsigned long flags; @@ -1794,6 +1813,7 @@ static struct iommu_domain *arm_smmu_domain_alloc(unsigned type) mutex_init(&smmu_domain->init_mutex); INIT_LIST_HEAD(&smmu_domain->devices); spin_lock_init(&smmu_domain->devices_lock); + INIT_LIST_HEAD(&smmu_domain->mmu_notifiers); return &smmu_domain->domain; } @@ -2589,6 +2609,9 @@ static struct iommu_ops arm_smmu_ops = { .dev_feat_enabled = arm_smmu_dev_feature_enabled, .dev_enable_feat = arm_smmu_dev_enable_feature, .dev_disable_feat = arm_smmu_dev_disable_feature, + .sva_bind = arm_smmu_sva_bind, + .sva_unbind = arm_smmu_sva_unbind, + .sva_get_pasid = arm_smmu_sva_get_pasid, .pgsize_bitmap = -1UL, /* Restricted during device attach */ }; @@ -3611,6 +3634,12 @@ static const struct of_device_id arm_smmu_of_match[] = { }; MODULE_DEVICE_TABLE(of, arm_smmu_of_match); +static void arm_smmu_driver_unregister(struct platform_driver *drv) +{ + arm_smmu_sva_notifier_synchronize(); + platform_driver_unregister(drv); +} + static struct platform_driver arm_smmu_driver = { .driver = { .name = "arm-smmu-v3", @@ -3621,7 +3650,8 @@ static struct platform_driver arm_smmu_driver = { .remove = arm_smmu_device_remove, .shutdown = arm_smmu_device_shutdown, }; -module_platform_driver(arm_smmu_driver); +module_driver(arm_smmu_driver, platform_driver_register, + arm_smmu_driver_unregister); MODULE_DESCRIPTION("IOMMU API for ARM architected SMMUv3 implementations"); MODULE_AUTHOR("Will Deacon <will@kernel.org>"); diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h index d4b7f40ccb02..96c2e9565e00 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h @@ -678,15 +678,25 @@ struct arm_smmu_domain { struct list_head devices; spinlock_t devices_lock; + + struct list_head mmu_notifiers; }; +static inline struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom) +{ + return container_of(dom, struct arm_smmu_domain, domain); +} + extern struct xarray arm_smmu_asid_xa; extern struct mutex arm_smmu_asid_lock; +extern struct arm_smmu_ctx_desc quiet_cd; int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid, struct arm_smmu_ctx_desc *cd); void arm_smmu_tlb_inv_asid(struct arm_smmu_device *smmu, u16 asid); bool arm_smmu_free_asid(struct arm_smmu_ctx_desc *cd); +int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain, int ssid, + unsigned long iova, size_t size); #ifdef CONFIG_ARM_SMMU_V3_SVA bool arm_smmu_sva_supported(struct arm_smmu_device *smmu); @@ -694,6 +704,11 @@ bool arm_smmu_master_sva_supported(struct arm_smmu_master *master); bool arm_smmu_master_sva_enabled(struct arm_smmu_master *master); int arm_smmu_master_enable_sva(struct arm_smmu_master *master); int arm_smmu_master_disable_sva(struct arm_smmu_master *master); +struct iommu_sva *arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm, + void *drvdata); +void arm_smmu_sva_unbind(struct iommu_sva *handle); +u32 arm_smmu_sva_get_pasid(struct iommu_sva *handle); +void arm_smmu_sva_notifier_synchronize(void); #else /* CONFIG_ARM_SMMU_V3_SVA */ static inline bool arm_smmu_sva_supported(struct arm_smmu_device *smmu) { @@ -719,5 +734,20 @@ static inline int arm_smmu_master_disable_sva(struct arm_smmu_master *master) { return -ENODEV; } + +static inline struct iommu_sva * +arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm, void *drvdata) +{ + return ERR_PTR(-ENODEV); +} + +static inline void arm_smmu_sva_unbind(struct iommu_sva *handle) {} + +static inline u32 arm_smmu_sva_get_pasid(struct iommu_sva *handle) +{ + return IOMMU_PASID_INVALID; +} + +static inline void arm_smmu_sva_notifier_synchronize(void) {} #endif /* CONFIG_ARM_SMMU_V3_SVA */ #endif /* _ARM_SMMU_V3_H */ diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 83674e32e58b..1ceebe2cfa35 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -5191,7 +5191,7 @@ static void auxiliary_unlink_device(struct dmar_domain *domain, domain->auxd_refcnt--; if (!domain->auxd_refcnt && domain->default_pasid > 0) - ioasid_free(domain->default_pasid); + ioasid_put(domain->default_pasid); } static int aux_domain_add_dev(struct dmar_domain *domain, @@ -5252,7 +5252,7 @@ attach_failed: spin_unlock(&iommu->lock); spin_unlock_irqrestore(&device_domain_lock, flags); if (!domain->auxd_refcnt && domain->default_pasid > 0) - ioasid_free(domain->default_pasid); + ioasid_put(domain->default_pasid); return ret; } diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c index 3242ebd0bca3..4fa248b98031 100644 --- a/drivers/iommu/intel/svm.c +++ b/drivers/iommu/intel/svm.c @@ -598,7 +598,7 @@ intel_svm_bind_mm(struct device *dev, unsigned int flags, if (mm) { ret = mmu_notifier_register(&svm->notifier, mm); if (ret) { - ioasid_free(svm->pasid); + ioasid_put(svm->pasid); kfree(svm); kfree(sdev); goto out; @@ -616,7 +616,7 @@ intel_svm_bind_mm(struct device *dev, unsigned int flags, if (ret) { if (mm) mmu_notifier_unregister(&svm->notifier, mm); - ioasid_free(svm->pasid); + ioasid_put(svm->pasid); kfree(svm); kfree(sdev); goto out; @@ -689,7 +689,7 @@ static int intel_svm_unbind_mm(struct device *dev, u32 pasid) kfree_rcu(sdev, rcu); if (list_empty(&svm->devs)) { - ioasid_free(svm->pasid); + ioasid_put(svm->pasid); if (svm->mm) { mmu_notifier_unregister(&svm->notifier, svm->mm); /* Clear mm's pasid. */ diff --git a/drivers/iommu/ioasid.c b/drivers/iommu/ioasid.c index 0f8dd377aada..50ee27bbd04e 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_free. + * free IOASIDs with ioasid_alloc and ioasid_put. */ #include <linux/ioasid.h> #include <linux/module.h> @@ -15,6 +15,7 @@ struct ioasid_data { struct ioasid_set *set; void *private; struct rcu_head rcu; + refcount_t refs; }; /* @@ -314,6 +315,7 @@ 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 @@ -346,11 +348,34 @@ exit_free: EXPORT_SYMBOL_GPL(ioasid_alloc); /** - * ioasid_free - Free an IOASID + * ioasid_get - obtain a reference to the IOASID + */ +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: 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. */ -void ioasid_free(ioasid_t ioasid) +bool ioasid_put(ioasid_t ioasid) { + bool free = false; struct ioasid_data *ioasid_data; spin_lock(&ioasid_allocator_lock); @@ -360,6 +385,10 @@ void ioasid_free(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) { @@ -369,8 +398,9 @@ void ioasid_free(ioasid_t ioasid) exit_unlock: spin_unlock(&ioasid_allocator_lock); + return free; } -EXPORT_SYMBOL_GPL(ioasid_free); +EXPORT_SYMBOL_GPL(ioasid_put); /** * ioasid_find - Find IOASID data diff --git a/drivers/iommu/iommu-sva-lib.c b/drivers/iommu/iommu-sva-lib.c new file mode 100644 index 000000000000..bd41405d34e9 --- /dev/null +++ b/drivers/iommu/iommu-sva-lib.c @@ -0,0 +1,86 @@ +// 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); diff --git a/drivers/iommu/iommu-sva-lib.h b/drivers/iommu/iommu-sva-lib.h new file mode 100644 index 000000000000..b40990aef3fd --- /dev/null +++ b/drivers/iommu/iommu-sva-lib.h @@ -0,0 +1,15 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * SVA library for IOMMU drivers + */ +#ifndef _IOMMU_SVA_LIB_H +#define _IOMMU_SVA_LIB_H + +#include <linux/ioasid.h> +#include <linux/mm_types.h> + +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); + +#endif /* _IOMMU_SVA_LIB_H */ diff --git a/include/linux/ioasid.h b/include/linux/ioasid.h index 6f000d7a0ddc..e9dacd4b9f6b 100644 --- a/include/linux/ioasid.h +++ b/include/linux/ioasid.h @@ -34,7 +34,8 @@ 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_free(ioasid_t ioasid); +void ioasid_get(ioasid_t ioasid); +bool ioasid_put(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); @@ -48,10 +49,15 @@ static inline ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, return INVALID_IOASID; } -static inline void ioasid_free(ioasid_t ioasid) +static inline void ioasid_get(ioasid_t ioasid) { } +static inline bool ioasid_put(ioasid_t ioasid) +{ + return false; +} + static inline void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid, bool (*getter)(void *)) { |