/* * Copyright © 2015 Intel Corporation. * * This program is free software; you can redistribute it and/or modify it * under the terms and conditions of the GNU General Public License, * version 2, as published by the Free Software Foundation. * * This program is distributed in the hope it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. * * Authors: David Woodhouse */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include "intel-pasid.h" #define PASID_ENTRY_P BIT_ULL(0) #define PASID_ENTRY_FLPM_5LP BIT_ULL(9) #define PASID_ENTRY_SRE BIT_ULL(11) static irqreturn_t prq_event_thread(int irq, void *d); struct pasid_state_entry { u64 val; }; int intel_svm_init(struct intel_iommu *iommu) { struct page *pages; int order; if (cpu_feature_enabled(X86_FEATURE_GBPAGES) && !cap_fl1gp_support(iommu->cap)) return -EINVAL; if (cpu_feature_enabled(X86_FEATURE_LA57) && !cap_5lp_support(iommu->cap)) return -EINVAL; /* Start at 2 because it's defined as 2^(1+PSS) */ iommu->pasid_max = 2 << ecap_pss(iommu->ecap); /* Eventually I'm promised we will get a multi-level PASID table * and it won't have to be physically contiguous. Until then, * limit the size because 8MiB contiguous allocations can be hard * to come by. The limit of 0x20000, which is 1MiB for each of * the PASID and PASID-state tables, is somewhat arbitrary. */ if (iommu->pasid_max > 0x20000) iommu->pasid_max = 0x20000; order = get_order(sizeof(struct pasid_entry) * iommu->pasid_max); if (ecap_dis(iommu->ecap)) { pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, order); if (pages) iommu->pasid_state_table = page_address(pages); else pr_warn("IOMMU: %s: Failed to allocate PASID state table\n", iommu->name); } return 0; } int intel_svm_exit(struct intel_iommu *iommu) { int order = get_order(sizeof(struct pasid_entry) * iommu->pasid_max); if (iommu->pasid_state_table) { free_pages((unsigned long)iommu->pasid_state_table, order); iommu->pasid_state_table = NULL; } return 0; } #define PRQ_ORDER 0 int intel_svm_enable_prq(struct intel_iommu *iommu) { struct page *pages; int irq, ret; pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, PRQ_ORDER); if (!pages) { pr_warn("IOMMU: %s: Failed to allocate page request queue\n", iommu->name); return -ENOMEM; } iommu->prq = page_address(pages); irq = dmar_alloc_hwirq(DMAR_UNITS_SUPPORTED + iommu->seq_id, iommu->node, iommu); if (irq <= 0) { pr_err("IOMMU: %s: Failed to create IRQ vector for page request queue\n", iommu->name); ret = -EINVAL; err: free_pages((unsigned long)iommu->prq, PRQ_ORDER); iommu->prq = NULL; return ret; } iommu->pr_irq = irq; snprintf(iommu->prq_name, sizeof(iommu->prq_name), "dmar%d-prq", iommu->seq_id); ret = request_threaded_irq(irq, NULL, prq_event_thread, IRQF_ONESHOT, iommu->prq_name, iommu); if (ret) { pr_err("IOMMU: %s: Failed to request IRQ for page request queue\n", iommu->name); dmar_free_hwirq(irq); iommu->pr_irq = 0; goto err; } dmar_writeq(iommu->reg + DMAR_PQH_REG, 0ULL); dmar_writeq(iommu->reg + DMAR_PQT_REG, 0ULL); dmar_writeq(iommu->reg + DMAR_PQA_REG, virt_to_phys(iommu->prq) | PRQ_ORDER); return 0; } int intel_svm_finish_prq(struct intel_iommu *iommu) { dmar_writeq(iommu->reg + DMAR_PQH_REG, 0ULL); dmar_writeq(iommu->reg + DMAR_PQT_REG, 0ULL); dmar_writeq(iommu->reg + DMAR_PQA_REG, 0ULL); if (iommu->pr_irq) { free_irq(iommu->pr_irq, iommu); dmar_free_hwirq(iommu->pr_irq); iommu->pr_irq = 0; } free_pages((unsigned long)iommu->prq, PRQ_ORDER); iommu->prq = NULL; return 0; } static void intel_flush_svm_range_dev (struct intel_svm *svm, struct intel_svm_dev *sdev, unsigned long address, unsigned long pages, int ih, int gl) { struct qi_desc desc; if (pages == -1) { /* For global kernel pages we have to flush them in *all* PASIDs * because that's the only option the hardware gives us. Despite * the fact that they are actually only accessible through one. */ if (gl) desc.qw0 = QI_EIOTLB_PASID(svm->pasid) | QI_EIOTLB_DID(sdev->did) | QI_EIOTLB_GRAN(QI_GRAN_ALL_ALL) | QI_EIOTLB_TYPE; else desc.qw0 = QI_EIOTLB_PASID(svm->pasid) | QI_EIOTLB_DID(sdev->did) | QI_EIOTLB_GRAN(QI_GRAN_NONG_PASID) | QI_EIOTLB_TYPE; desc.qw1 = 0; } else { int mask = ilog2(__roundup_pow_of_two(pages)); desc.qw0 = QI_EIOTLB_PASID(svm->pasid) | QI_EIOTLB_DID(sdev->did) | QI_EIOTLB_GRAN(QI_GRAN_PSI_PASID) | QI_EIOTLB_TYPE; desc.qw1 = QI_EIOTLB_ADDR(address) | QI_EIOTLB_GL(gl) | QI_EIOTLB_IH(ih) | QI_EIOTLB_AM(mask); } desc.qw2 = 0; desc.qw3 = 0; qi_submit_sync(&desc, svm->iommu); if (sdev->dev_iotlb) { desc.qw0 = QI_DEV_EIOTLB_PASID(svm->pasid) | QI_DEV_EIOTLB_SID(sdev->sid) | QI_DEV_EIOTLB_QDEP(sdev->qdep) | QI_DEIOTLB_TYPE; if (pages == -1) { desc.qw1 = QI_DEV_EIOTLB_ADDR(-1ULL >> 1) | QI_DEV_EIOTLB_SIZE; } else if (pages > 1) { /* The least significant zero bit indicates the size. So, * for example, an "address" value of 0x12345f000 will * flush from 0x123440000 to 0x12347ffff (256KiB). */ unsigned long last = address + ((unsigned long)(pages - 1) << VTD_PAGE_SHIFT); unsigned long mask = __rounddown_pow_of_two(address ^ last); desc.qw1 = QI_DEV_EIOTLB_ADDR((address & ~mask) | (mask - 1)) | QI_DEV_EIOTLB_SIZE; } else { desc.qw1 = QI_DEV_EIOTLB_ADDR(address); } desc.qw2 = 0; desc.qw3 = 0; qi_submit_sync(&desc, svm->iommu); } } static void intel_flush_svm_range(struct intel_svm *svm, unsigned long address, unsigned long pages, int ih, int gl) { struct intel_svm_dev *sdev; /* Try deferred invalidate if available */ if (svm->iommu->pasid_state_table && !cmpxchg64(&svm->iommu->pasid_state_table[svm->pasid].val, 0, 1ULL << 63)) return; rcu_read_lock(); list_for_each_entry_rcu(sdev, &svm->devs, list) intel_flush_svm_range_dev(svm, sdev, address, pages, ih, gl); rcu_read_unlock(); } static void intel_change_pte(struct mmu_notifier *mn, struct mm_struct *mm, unsigned long address, pte_t pte) { struct intel_svm *svm = container_of(mn, struct intel_svm, notifier); intel_flush_svm_range(svm, address, 1, 1, 0); } /* Pages have been freed at this point */ static void intel_invalidate_range(struct mmu_notifier *mn, struct mm_struct *mm, unsigned long start, unsigned long end) { struct intel_svm *svm = container_of(mn, struct intel_svm, notifier); intel_flush_svm_range(svm, start, (end - start + PAGE_SIZE - 1) >> VTD_PAGE_SHIFT, 0, 0); } static void intel_flush_pasid_dev(struct intel_svm *svm, struct intel_svm_dev *sdev, int pasid) { struct qi_desc desc; desc.qw0 = QI_PC_TYPE | QI_PC_DID(sdev->did) | QI_PC_PASID_SEL | QI_PC_PASID(pasid); desc.qw1 = 0; desc.qw2 = 0; desc.qw3 = 0; qi_submit_sync(&desc, svm->iommu); } static void intel_mm_release(struct mmu_notifier *mn, struct mm_struct *mm) { struct intel_svm *svm = container_of(mn, struct intel_svm, notifier); struct intel_svm_dev *sdev; /* This might end up being called from exit_mmap(), *before* the page * tables are cleared. And __mmu_notifier_release() will delete us from * the list of notifiers so that our invalidate_range() callback doesn't * get called when the page tables are cleared. So we need to protect * against hardware accessing those page tables. * * We do it by clearing the entry in the PASID table and then flushing * the IOTLB and the PASID table caches. This might upset hardware; * perhaps we'll want to point the PASID to a dummy PGD (like the zero * page) so that we end up taking a fault that the hardware really * *has* to handle gracefully without affecting other processes. */ rcu_read_lock(); list_for_each_entry_rcu(sdev, &svm->devs, list) { intel_pasid_clear_entry(sdev->dev, svm->pasid); intel_flush_pasid_dev(svm, sdev, svm->pasid); intel_flush_svm_range_dev(svm, sdev, 0, -1, 0, !svm->mm); } rcu_read_unlock(); } static const struct mmu_notifier_ops intel_mmuops = { .release = intel_mm_release, .change_pte = intel_change_pte, .invalidate_range = intel_invalidate_range, }; static DEFINE_MUTEX(pasid_mutex); static LIST_HEAD(global_svm_list); int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_ops *ops) { struct intel_iommu *iommu = intel_svm_device_to_iommu(dev); struct pasid_entry *entry; struct intel_svm_dev *sdev; struct intel_svm *svm = NULL; struct mm_struct *mm = NULL; u64 pasid_entry_val; int pasid_max; int ret; if (!iommu) return -EINVAL; if (dev_is_pci(dev)) { pasid_max = pci_max_pasids(to_pci_dev(dev)); if (pasid_max < 0) return -EINVAL; } else pasid_max = 1 << 20; if (flags & SVM_FLAG_SUPERVISOR_MODE) { if (!ecap_srs(iommu->ecap)) return -EINVAL; } else if (pasid) { mm = get_task_mm(current); BUG_ON(!mm); } mutex_lock(&pasid_mutex); if (pasid && !(flags & SVM_FLAG_PRIVATE_PASID)) { struct intel_svm *t; list_for_each_entry(t, &global_svm_list, list) { if (t->mm != mm || (t->flags & SVM_FLAG_PRIVATE_PASID)) continue; svm = t; if (svm->pasid >= pasid_max) { dev_warn(dev, "Limited PASID width. Cannot use existing PASID %d\n", svm->pasid); ret = -ENOSPC; goto out; } list_for_each_entry(sdev, &svm->devs, list) { if (dev == sdev->dev) { if (sdev->ops != ops) { ret = -EBUSY; goto out; } sdev->users++; goto success; } } break; } } sdev = kzalloc(sizeof(*sdev), GFP_KERNEL); if (!sdev) { ret = -ENOMEM; goto out; } sdev->dev = dev; ret = intel_iommu_enable_pasid(iommu, sdev); if (ret || !pasid) { /* If they don't actually want to assign a PASID, this is * just an enabling check/preparation. */ kfree(sdev); goto out; } /* Finish the setup now we know we're keeping it */ sdev->users = 1; sdev->ops = ops; init_rcu_head(&sdev->rcu); if (!svm) { svm = kzalloc(sizeof(*svm), GFP_KERNEL); if (!svm) { ret = -ENOMEM; kfree(sdev); goto out; } svm->iommu = iommu; if (pasid_max > intel_pasid_max_id) pasid_max = intel_pasid_max_id; /* Do not use PASID 0 in caching mode (virtualised IOMMU) */ ret = intel_pasid_alloc_id(svm, !!cap_caching_mode(iommu->cap), pasid_max - 1, GFP_KERNEL); if (ret < 0) { kfree(svm); kfree(sdev); goto out; } svm->pasid = ret; svm->notifier.ops = &intel_mmuops; svm->mm = mm; svm->flags = flags; INIT_LIST_HEAD_RCU(&svm->devs); INIT_LIST_HEAD(&svm->list); ret = -ENOMEM; if (mm) { ret = mmu_notifier_register(&svm->notifier, mm); if (ret) { intel_pasid_free_id(svm->pasid); kfree(svm); kfree(sdev); goto out; } pasid_entry_val = (u64)__pa(mm->pgd) | PASID_ENTRY_P; } else pasid_entry_val = (u64)__pa(init_mm.pgd) | PASID_ENTRY_P | PASID_ENTRY_SRE; if (cpu_feature_enabled(X86_FEATURE_LA57)) pasid_entry_val |= PASID_ENTRY_FLPM_5LP; entry = intel_pasid_get_entry(dev, svm->pasid); WRITE_ONCE(entry->val[0], pasid_entry_val); /* * Flush PASID cache when a PASID table entry becomes * present. */ if (cap_caching_mode(iommu->cap)) intel_flush_pasid_dev(svm, sdev, svm->pasid); list_add_tail(&svm->list, &global_svm_list); } list_add_rcu(&sdev->list, &svm->devs); success: *pasid = svm->pasid; ret = 0; out: mutex_unlock(&pasid_mutex); if (mm) mmput(mm); return ret; } EXPORT_SYMBOL_GPL(intel_svm_bind_mm); int intel_svm_unbind_mm(struct device *dev, int pasid) { struct intel_svm_dev *sdev; struct intel_iommu *iommu; struct intel_svm *svm; int ret = -EINVAL; mutex_lock(&pasid_mutex); iommu = intel_svm_device_to_iommu(dev); if (!iommu) goto out; svm = intel_pasid_lookup_id(pasid); if (!svm) goto out; list_for_each_entry(sdev, &svm->devs, list) { if (dev == sdev->dev) { ret = 0; sdev->users--; if (!sdev->users) { list_del_rcu(&sdev->list); /* Flush the PASID cache and IOTLB for this device. * Note that we do depend on the hardware *not* using * the PASID any more. Just as we depend on other * devices never using PASIDs that they have no right * to use. We have a *shared* PASID table, because it's * large and has to be physically contiguous. So it's * hard to be as defensive as we might like. */ intel_flush_pasid_dev(svm, sdev, svm->pasid); intel_flush_svm_range_dev(svm, sdev, 0, -1, 0, !svm->mm); kfree_rcu(sdev, rcu); intel_pasid_clear_entry(dev, svm->pasid); if (list_empty(&svm->devs)) { intel_pasid_free_id(svm->pasid); if (svm->mm) mmu_notifier_unregister(&svm->notifier, svm->mm); list_del(&svm->list); /* We mandate that no page faults may be outstanding * for the PASID when intel_svm_unbind_mm() is called. * If that is not obeyed, subtle errors will happen. * Let's make them less subtle... */ memset(svm, 0x6b, sizeof(*svm)); kfree(svm); } } break; } } out: mutex_unlock(&pasid_mutex); return ret; } EXPORT_SYMBOL_GPL(intel_svm_unbind_mm); int intel_svm_is_pasid_valid(struct device *dev, int pasid) { struct intel_iommu *iommu; struct intel_svm *svm; int ret = -EINVAL; mutex_lock(&pasid_mutex); iommu = intel_svm_device_to_iommu(dev); if (!iommu) goto out; svm = intel_pasid_lookup_id(pasid); if (!svm) goto out; /* init_mm is used in this case */ if (!svm->mm) ret = 1; else if (atomic_read(&svm->mm->mm_users) > 0) ret = 1; else ret = 0; out: mutex_unlock(&pasid_mutex); return ret; } EXPORT_SYMBOL_GPL(intel_svm_is_pasid_valid); /* Page request queue descriptor */ struct page_req_dsc { u64 srr:1; u64 bof:1; u64 pasid_present:1; u64 lpig:1; u64 pasid:20; u64 bus:8; u64 private:23; u64 prg_index:9; u64 rd_req:1; u64 wr_req:1; u64 exe_req:1; u64 priv_req:1; u64 devfn:8; u64 addr:52; }; #define PRQ_RING_MASK ((0x1000 << PRQ_ORDER) - 0x10) static bool access_error(struct vm_area_struct *vma, struct page_req_dsc *req) { unsigned long requested = 0; if (req->exe_req) requested |= VM_EXEC; if (req->rd_req) requested |= VM_READ; if (req->wr_req) requested |= VM_WRITE; return (requested & ~vma->vm_flags) != 0; } static bool is_canonical_address(u64 addr) { int shift = 64 - (__VIRTUAL_MASK_SHIFT + 1); long saddr = (long) addr; return (((saddr << shift) >> shift) == saddr); } static irqreturn_t prq_event_thread(int irq, void *d) { struct intel_iommu *iommu = d; struct intel_svm *svm = NULL; int head, tail, handled = 0; /* Clear PPR bit before reading head/tail registers, to * ensure that we get a new interrupt if needed. */ writel(DMA_PRS_PPR, iommu->reg + DMAR_PRS_REG); tail = dmar_readq(iommu->reg + DMAR_PQT_REG) & PRQ_RING_MASK; head = dmar_readq(iommu->reg + DMAR_PQH_REG) & PRQ_RING_MASK; while (head != tail) { struct intel_svm_dev *sdev; struct vm_area_struct *vma; struct page_req_dsc *req; struct qi_desc resp; int result; vm_fault_t ret; u64 address; handled = 1; req = &iommu->prq[head / sizeof(*req)]; result = QI_RESP_FAILURE; address = (u64)req->addr << VTD_PAGE_SHIFT; if (!req->pasid_present) { pr_err("%s: Page request without PASID: %08llx %08llx\n", iommu->name, ((unsigned long long *)req)[0], ((unsigned long long *)req)[1]); goto bad_req; } if (!svm || svm->pasid != req->pasid) { rcu_read_lock(); svm = intel_pasid_lookup_id(req->pasid); /* It *can't* go away, because the driver is not permitted * to unbind the mm while any page faults are outstanding. * So we only need RCU to protect the internal idr code. */ rcu_read_unlock(); if (!svm) { pr_err("%s: Page request for invalid PASID %d: %08llx %08llx\n", iommu->name, req->pasid, ((unsigned long long *)req)[0], ((unsigned long long *)req)[1]); goto no_pasid; } } result = QI_RESP_INVALID; /* Since we're using init_mm.pgd directly, we should never take * any faults on kernel addresses. */ if (!svm->mm) goto bad_req; /* If the mm is already defunct, don't handle faults. */ if (!mmget_not_zero(svm->mm)) goto bad_req; /* If address is not canonical, return invalid response */ if (!is_canonical_address(address)) goto bad_req; down_read(&svm->mm->mmap_sem); vma = find_extend_vma(svm->mm, address); if (!vma || address < vma->vm_start) goto invalid; if (access_error(vma, req)) goto invalid; ret = handle_mm_fault(vma, address, req->wr_req ? FAULT_FLAG_WRITE : 0); if (ret & VM_FAULT_ERROR) goto invalid; result = QI_RESP_SUCCESS; invalid: up_read(&svm->mm->mmap_sem); mmput(svm->mm); bad_req: /* Accounting for major/minor faults? */ rcu_read_lock(); list_for_each_entry_rcu(sdev, &svm->devs, list) { if (sdev->sid == PCI_DEVID(req->bus, req->devfn)) break; } /* Other devices can go away, but the drivers are not permitted * to unbind while any page faults might be in flight. So it's * OK to drop the 'lock' here now we have it. */ rcu_read_unlock(); if (WARN_ON(&sdev->list == &svm->devs)) sdev = NULL; if (sdev && sdev->ops && sdev->ops->fault_cb) { int rwxp = (req->rd_req << 3) | (req->wr_req << 2) | (req->exe_req << 1) | (req->priv_req); sdev->ops->fault_cb(sdev->dev, req->pasid, req->addr, req->private, rwxp, result); } /* We get here in the error case where the PASID lookup failed, and these can be NULL. Do not use them below this point! */ sdev = NULL; svm = NULL; no_pasid: if (req->lpig) { /* Page Group Response */ resp.qw0 = QI_PGRP_PASID(req->pasid) | QI_PGRP_DID((req->bus << 8) | req->devfn) | QI_PGRP_PASID_P(req->pasid_present) | QI_PGRP_RESP_TYPE; resp.qw1 = QI_PGRP_IDX(req->prg_index) | QI_PGRP_PRIV(req->private) | QI_PGRP_RESP_CODE(result); } else if (req->srr) { /* Page Stream Response */ resp.qw0 = QI_PSTRM_IDX(req->prg_index) | QI_PSTRM_PRIV(req->private) | QI_PSTRM_BUS(req->bus) | QI_PSTRM_PASID(req->pasid) | QI_PSTRM_RESP_TYPE; resp.qw1 = QI_PSTRM_ADDR(address) | QI_PSTRM_DEVFN(req->devfn) | QI_PSTRM_RESP_CODE(result); } resp.qw2 = 0; resp.qw3 = 0; qi_submit_sync(&resp, iommu); head = (head + sizeof(*req)) & PRQ_RING_MASK; } dmar_writeq(iommu->reg + DMAR_PQH_REG, tail); return IRQ_RETVAL(handled); }