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0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  *
0004  * Copyright 2010 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
0005  * Copyright 2011 David Gibson, IBM Corporation <dwg@au1.ibm.com>
0006  * Copyright 2016 Alexey Kardashevskiy, IBM Corporation <aik@au1.ibm.com>
0007  */
0008 
0009 #include <linux/types.h>
0010 #include <linux/string.h>
0011 #include <linux/kvm.h>
0012 #include <linux/kvm_host.h>
0013 #include <linux/highmem.h>
0014 #include <linux/gfp.h>
0015 #include <linux/slab.h>
0016 #include <linux/sched/signal.h>
0017 #include <linux/hugetlb.h>
0018 #include <linux/list.h>
0019 #include <linux/anon_inodes.h>
0020 #include <linux/iommu.h>
0021 #include <linux/file.h>
0022 #include <linux/mm.h>
0023 
0024 #include <asm/kvm_ppc.h>
0025 #include <asm/kvm_book3s.h>
0026 #include <asm/book3s/64/mmu-hash.h>
0027 #include <asm/hvcall.h>
0028 #include <asm/synch.h>
0029 #include <asm/ppc-opcode.h>
0030 #include <asm/udbg.h>
0031 #include <asm/iommu.h>
0032 #include <asm/tce.h>
0033 #include <asm/mmu_context.h>
0034 
0035 static struct kvmppc_spapr_tce_table *kvmppc_find_table(struct kvm *kvm,
0036     unsigned long liobn)
0037 {
0038     struct kvmppc_spapr_tce_table *stt;
0039 
0040     list_for_each_entry_lockless(stt, &kvm->arch.spapr_tce_tables, list)
0041         if (stt->liobn == liobn)
0042             return stt;
0043 
0044     return NULL;
0045 }
0046 
0047 static unsigned long kvmppc_tce_pages(unsigned long iommu_pages)
0048 {
0049     return ALIGN(iommu_pages * sizeof(u64), PAGE_SIZE) / PAGE_SIZE;
0050 }
0051 
0052 static unsigned long kvmppc_stt_pages(unsigned long tce_pages)
0053 {
0054     unsigned long stt_bytes = sizeof(struct kvmppc_spapr_tce_table) +
0055             (tce_pages * sizeof(struct page *));
0056 
0057     return tce_pages + ALIGN(stt_bytes, PAGE_SIZE) / PAGE_SIZE;
0058 }
0059 
0060 static void kvm_spapr_tce_iommu_table_free(struct rcu_head *head)
0061 {
0062     struct kvmppc_spapr_tce_iommu_table *stit = container_of(head,
0063             struct kvmppc_spapr_tce_iommu_table, rcu);
0064 
0065     iommu_tce_table_put(stit->tbl);
0066 
0067     kfree(stit);
0068 }
0069 
0070 static void kvm_spapr_tce_liobn_put(struct kref *kref)
0071 {
0072     struct kvmppc_spapr_tce_iommu_table *stit = container_of(kref,
0073             struct kvmppc_spapr_tce_iommu_table, kref);
0074 
0075     list_del_rcu(&stit->next);
0076 
0077     call_rcu(&stit->rcu, kvm_spapr_tce_iommu_table_free);
0078 }
0079 
0080 extern void kvm_spapr_tce_release_iommu_group(struct kvm *kvm,
0081         struct iommu_group *grp)
0082 {
0083     int i;
0084     struct kvmppc_spapr_tce_table *stt;
0085     struct kvmppc_spapr_tce_iommu_table *stit, *tmp;
0086     struct iommu_table_group *table_group = NULL;
0087 
0088     rcu_read_lock();
0089     list_for_each_entry_rcu(stt, &kvm->arch.spapr_tce_tables, list) {
0090 
0091         table_group = iommu_group_get_iommudata(grp);
0092         if (WARN_ON(!table_group))
0093             continue;
0094 
0095         list_for_each_entry_safe(stit, tmp, &stt->iommu_tables, next) {
0096             for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
0097                 if (table_group->tables[i] != stit->tbl)
0098                     continue;
0099 
0100                 kref_put(&stit->kref, kvm_spapr_tce_liobn_put);
0101             }
0102         }
0103         cond_resched_rcu();
0104     }
0105     rcu_read_unlock();
0106 }
0107 
0108 extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd,
0109         struct iommu_group *grp)
0110 {
0111     struct kvmppc_spapr_tce_table *stt = NULL;
0112     bool found = false;
0113     struct iommu_table *tbl = NULL;
0114     struct iommu_table_group *table_group;
0115     long i;
0116     struct kvmppc_spapr_tce_iommu_table *stit;
0117     struct fd f;
0118 
0119     f = fdget(tablefd);
0120     if (!f.file)
0121         return -EBADF;
0122 
0123     rcu_read_lock();
0124     list_for_each_entry_rcu(stt, &kvm->arch.spapr_tce_tables, list) {
0125         if (stt == f.file->private_data) {
0126             found = true;
0127             break;
0128         }
0129     }
0130     rcu_read_unlock();
0131 
0132     fdput(f);
0133 
0134     if (!found)
0135         return -EINVAL;
0136 
0137     table_group = iommu_group_get_iommudata(grp);
0138     if (WARN_ON(!table_group))
0139         return -EFAULT;
0140 
0141     for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
0142         struct iommu_table *tbltmp = table_group->tables[i];
0143 
0144         if (!tbltmp)
0145             continue;
0146         /* Make sure hardware table parameters are compatible */
0147         if ((tbltmp->it_page_shift <= stt->page_shift) &&
0148                 (tbltmp->it_offset << tbltmp->it_page_shift ==
0149                  stt->offset << stt->page_shift) &&
0150                 (tbltmp->it_size << tbltmp->it_page_shift >=
0151                  stt->size << stt->page_shift)) {
0152             /*
0153              * Reference the table to avoid races with
0154              * add/remove DMA windows.
0155              */
0156             tbl = iommu_tce_table_get(tbltmp);
0157             break;
0158         }
0159     }
0160     if (!tbl)
0161         return -EINVAL;
0162 
0163     rcu_read_lock();
0164     list_for_each_entry_rcu(stit, &stt->iommu_tables, next) {
0165         if (tbl != stit->tbl)
0166             continue;
0167 
0168         if (!kref_get_unless_zero(&stit->kref)) {
0169             /* stit is being destroyed */
0170             iommu_tce_table_put(tbl);
0171             rcu_read_unlock();
0172             return -ENOTTY;
0173         }
0174         /*
0175          * The table is already known to this KVM, we just increased
0176          * its KVM reference counter and can return.
0177          */
0178         rcu_read_unlock();
0179         return 0;
0180     }
0181     rcu_read_unlock();
0182 
0183     stit = kzalloc(sizeof(*stit), GFP_KERNEL);
0184     if (!stit) {
0185         iommu_tce_table_put(tbl);
0186         return -ENOMEM;
0187     }
0188 
0189     stit->tbl = tbl;
0190     kref_init(&stit->kref);
0191 
0192     list_add_rcu(&stit->next, &stt->iommu_tables);
0193 
0194     return 0;
0195 }
0196 
0197 static void release_spapr_tce_table(struct rcu_head *head)
0198 {
0199     struct kvmppc_spapr_tce_table *stt = container_of(head,
0200             struct kvmppc_spapr_tce_table, rcu);
0201     unsigned long i, npages = kvmppc_tce_pages(stt->size);
0202 
0203     for (i = 0; i < npages; i++)
0204         if (stt->pages[i])
0205             __free_page(stt->pages[i]);
0206 
0207     kfree(stt);
0208 }
0209 
0210 static struct page *kvm_spapr_get_tce_page(struct kvmppc_spapr_tce_table *stt,
0211         unsigned long sttpage)
0212 {
0213     struct page *page = stt->pages[sttpage];
0214 
0215     if (page)
0216         return page;
0217 
0218     mutex_lock(&stt->alloc_lock);
0219     page = stt->pages[sttpage];
0220     if (!page) {
0221         page = alloc_page(GFP_KERNEL | __GFP_ZERO);
0222         WARN_ON_ONCE(!page);
0223         if (page)
0224             stt->pages[sttpage] = page;
0225     }
0226     mutex_unlock(&stt->alloc_lock);
0227 
0228     return page;
0229 }
0230 
0231 static vm_fault_t kvm_spapr_tce_fault(struct vm_fault *vmf)
0232 {
0233     struct kvmppc_spapr_tce_table *stt = vmf->vma->vm_file->private_data;
0234     struct page *page;
0235 
0236     if (vmf->pgoff >= kvmppc_tce_pages(stt->size))
0237         return VM_FAULT_SIGBUS;
0238 
0239     page = kvm_spapr_get_tce_page(stt, vmf->pgoff);
0240     if (!page)
0241         return VM_FAULT_OOM;
0242 
0243     get_page(page);
0244     vmf->page = page;
0245     return 0;
0246 }
0247 
0248 static const struct vm_operations_struct kvm_spapr_tce_vm_ops = {
0249     .fault = kvm_spapr_tce_fault,
0250 };
0251 
0252 static int kvm_spapr_tce_mmap(struct file *file, struct vm_area_struct *vma)
0253 {
0254     vma->vm_ops = &kvm_spapr_tce_vm_ops;
0255     return 0;
0256 }
0257 
0258 static int kvm_spapr_tce_release(struct inode *inode, struct file *filp)
0259 {
0260     struct kvmppc_spapr_tce_table *stt = filp->private_data;
0261     struct kvmppc_spapr_tce_iommu_table *stit, *tmp;
0262     struct kvm *kvm = stt->kvm;
0263 
0264     mutex_lock(&kvm->lock);
0265     list_del_rcu(&stt->list);
0266     mutex_unlock(&kvm->lock);
0267 
0268     list_for_each_entry_safe(stit, tmp, &stt->iommu_tables, next) {
0269         WARN_ON(!kref_read(&stit->kref));
0270         while (1) {
0271             if (kref_put(&stit->kref, kvm_spapr_tce_liobn_put))
0272                 break;
0273         }
0274     }
0275 
0276     account_locked_vm(kvm->mm,
0277         kvmppc_stt_pages(kvmppc_tce_pages(stt->size)), false);
0278 
0279     kvm_put_kvm(stt->kvm);
0280 
0281     call_rcu(&stt->rcu, release_spapr_tce_table);
0282 
0283     return 0;
0284 }
0285 
0286 static const struct file_operations kvm_spapr_tce_fops = {
0287     .mmap           = kvm_spapr_tce_mmap,
0288     .release    = kvm_spapr_tce_release,
0289 };
0290 
0291 long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
0292                    struct kvm_create_spapr_tce_64 *args)
0293 {
0294     struct kvmppc_spapr_tce_table *stt = NULL;
0295     struct kvmppc_spapr_tce_table *siter;
0296     struct mm_struct *mm = kvm->mm;
0297     unsigned long npages, size = args->size;
0298     int ret;
0299 
0300     if (!args->size || args->page_shift < 12 || args->page_shift > 34 ||
0301         (args->offset + args->size > (ULLONG_MAX >> args->page_shift)))
0302         return -EINVAL;
0303 
0304     npages = kvmppc_tce_pages(size);
0305     ret = account_locked_vm(mm, kvmppc_stt_pages(npages), true);
0306     if (ret)
0307         return ret;
0308 
0309     ret = -ENOMEM;
0310     stt = kzalloc(struct_size(stt, pages, npages), GFP_KERNEL | __GFP_NOWARN);
0311     if (!stt)
0312         goto fail_acct;
0313 
0314     stt->liobn = args->liobn;
0315     stt->page_shift = args->page_shift;
0316     stt->offset = args->offset;
0317     stt->size = size;
0318     stt->kvm = kvm;
0319     mutex_init(&stt->alloc_lock);
0320     INIT_LIST_HEAD_RCU(&stt->iommu_tables);
0321 
0322     mutex_lock(&kvm->lock);
0323 
0324     /* Check this LIOBN hasn't been previously allocated */
0325     ret = 0;
0326     list_for_each_entry(siter, &kvm->arch.spapr_tce_tables, list) {
0327         if (siter->liobn == args->liobn) {
0328             ret = -EBUSY;
0329             break;
0330         }
0331     }
0332 
0333     kvm_get_kvm(kvm);
0334     if (!ret)
0335         ret = anon_inode_getfd("kvm-spapr-tce", &kvm_spapr_tce_fops,
0336                        stt, O_RDWR | O_CLOEXEC);
0337 
0338     if (ret >= 0)
0339         list_add_rcu(&stt->list, &kvm->arch.spapr_tce_tables);
0340     else
0341         kvm_put_kvm_no_destroy(kvm);
0342 
0343     mutex_unlock(&kvm->lock);
0344 
0345     if (ret >= 0)
0346         return ret;
0347 
0348     kfree(stt);
0349  fail_acct:
0350     account_locked_vm(mm, kvmppc_stt_pages(npages), false);
0351     return ret;
0352 }
0353 
0354 static long kvmppc_tce_to_ua(struct kvm *kvm, unsigned long tce,
0355         unsigned long *ua)
0356 {
0357     unsigned long gfn = tce >> PAGE_SHIFT;
0358     struct kvm_memory_slot *memslot;
0359 
0360     memslot = __gfn_to_memslot(kvm_memslots(kvm), gfn);
0361     if (!memslot)
0362         return -EINVAL;
0363 
0364     *ua = __gfn_to_hva_memslot(memslot, gfn) |
0365         (tce & ~(PAGE_MASK | TCE_PCI_READ | TCE_PCI_WRITE));
0366 
0367     return 0;
0368 }
0369 
0370 static long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *stt,
0371         unsigned long tce)
0372 {
0373     unsigned long gpa = tce & ~(TCE_PCI_READ | TCE_PCI_WRITE);
0374     enum dma_data_direction dir = iommu_tce_direction(tce);
0375     struct kvmppc_spapr_tce_iommu_table *stit;
0376     unsigned long ua = 0;
0377 
0378     /* Allow userspace to poison TCE table */
0379     if (dir == DMA_NONE)
0380         return H_SUCCESS;
0381 
0382     if (iommu_tce_check_gpa(stt->page_shift, gpa))
0383         return H_TOO_HARD;
0384 
0385     if (kvmppc_tce_to_ua(stt->kvm, tce, &ua))
0386         return H_TOO_HARD;
0387 
0388     rcu_read_lock();
0389     list_for_each_entry_rcu(stit, &stt->iommu_tables, next) {
0390         unsigned long hpa = 0;
0391         struct mm_iommu_table_group_mem_t *mem;
0392         long shift = stit->tbl->it_page_shift;
0393 
0394         mem = mm_iommu_lookup(stt->kvm->mm, ua, 1ULL << shift);
0395         if (!mem || mm_iommu_ua_to_hpa(mem, ua, shift, &hpa)) {
0396             rcu_read_unlock();
0397             return H_TOO_HARD;
0398         }
0399     }
0400     rcu_read_unlock();
0401 
0402     return H_SUCCESS;
0403 }
0404 
0405 /*
0406  * Handles TCE requests for emulated devices.
0407  * Puts guest TCE values to the table and expects user space to convert them.
0408  * Cannot fail so kvmppc_tce_validate must be called before it.
0409  */
0410 static void kvmppc_tce_put(struct kvmppc_spapr_tce_table *stt,
0411         unsigned long idx, unsigned long tce)
0412 {
0413     struct page *page;
0414     u64 *tbl;
0415     unsigned long sttpage;
0416 
0417     idx -= stt->offset;
0418     sttpage = idx / TCES_PER_PAGE;
0419     page = stt->pages[sttpage];
0420 
0421     if (!page) {
0422         /* We allow any TCE, not just with read|write permissions */
0423         if (!tce)
0424             return;
0425 
0426         page = kvm_spapr_get_tce_page(stt, sttpage);
0427         if (!page)
0428             return;
0429     }
0430     tbl = page_to_virt(page);
0431 
0432     tbl[idx % TCES_PER_PAGE] = tce;
0433 }
0434 
0435 static void kvmppc_clear_tce(struct mm_struct *mm, struct kvmppc_spapr_tce_table *stt,
0436         struct iommu_table *tbl, unsigned long entry)
0437 {
0438     unsigned long i;
0439     unsigned long subpages = 1ULL << (stt->page_shift - tbl->it_page_shift);
0440     unsigned long io_entry = entry << (stt->page_shift - tbl->it_page_shift);
0441 
0442     for (i = 0; i < subpages; ++i) {
0443         unsigned long hpa = 0;
0444         enum dma_data_direction dir = DMA_NONE;
0445 
0446         iommu_tce_xchg_no_kill(mm, tbl, io_entry + i, &hpa, &dir);
0447     }
0448 }
0449 
0450 static long kvmppc_tce_iommu_mapped_dec(struct kvm *kvm,
0451         struct iommu_table *tbl, unsigned long entry)
0452 {
0453     struct mm_iommu_table_group_mem_t *mem = NULL;
0454     const unsigned long pgsize = 1ULL << tbl->it_page_shift;
0455     __be64 *pua = IOMMU_TABLE_USERSPACE_ENTRY_RO(tbl, entry);
0456 
0457     if (!pua)
0458         return H_SUCCESS;
0459 
0460     mem = mm_iommu_lookup(kvm->mm, be64_to_cpu(*pua), pgsize);
0461     if (!mem)
0462         return H_TOO_HARD;
0463 
0464     mm_iommu_mapped_dec(mem);
0465 
0466     *pua = cpu_to_be64(0);
0467 
0468     return H_SUCCESS;
0469 }
0470 
0471 static long kvmppc_tce_iommu_do_unmap(struct kvm *kvm,
0472         struct iommu_table *tbl, unsigned long entry)
0473 {
0474     enum dma_data_direction dir = DMA_NONE;
0475     unsigned long hpa = 0;
0476     long ret;
0477 
0478     if (WARN_ON_ONCE(iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa,
0479                     &dir)))
0480         return H_TOO_HARD;
0481 
0482     if (dir == DMA_NONE)
0483         return H_SUCCESS;
0484 
0485     ret = kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry);
0486     if (ret != H_SUCCESS)
0487         iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa, &dir);
0488 
0489     return ret;
0490 }
0491 
0492 static long kvmppc_tce_iommu_unmap(struct kvm *kvm,
0493         struct kvmppc_spapr_tce_table *stt, struct iommu_table *tbl,
0494         unsigned long entry)
0495 {
0496     unsigned long i, ret = H_SUCCESS;
0497     unsigned long subpages = 1ULL << (stt->page_shift - tbl->it_page_shift);
0498     unsigned long io_entry = entry * subpages;
0499 
0500     for (i = 0; i < subpages; ++i) {
0501         ret = kvmppc_tce_iommu_do_unmap(kvm, tbl, io_entry + i);
0502         if (ret != H_SUCCESS)
0503             break;
0504     }
0505 
0506     iommu_tce_kill(tbl, io_entry, subpages);
0507 
0508     return ret;
0509 }
0510 
0511 static long kvmppc_tce_iommu_do_map(struct kvm *kvm, struct iommu_table *tbl,
0512         unsigned long entry, unsigned long ua,
0513         enum dma_data_direction dir)
0514 {
0515     long ret;
0516     unsigned long hpa;
0517     __be64 *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry);
0518     struct mm_iommu_table_group_mem_t *mem;
0519 
0520     if (!pua)
0521         /* it_userspace allocation might be delayed */
0522         return H_TOO_HARD;
0523 
0524     mem = mm_iommu_lookup(kvm->mm, ua, 1ULL << tbl->it_page_shift);
0525     if (!mem)
0526         /* This only handles v2 IOMMU type, v1 is handled via ioctl() */
0527         return H_TOO_HARD;
0528 
0529     if (WARN_ON_ONCE(mm_iommu_ua_to_hpa(mem, ua, tbl->it_page_shift, &hpa)))
0530         return H_TOO_HARD;
0531 
0532     if (mm_iommu_mapped_inc(mem))
0533         return H_TOO_HARD;
0534 
0535     ret = iommu_tce_xchg_no_kill(kvm->mm, tbl, entry, &hpa, &dir);
0536     if (WARN_ON_ONCE(ret)) {
0537         mm_iommu_mapped_dec(mem);
0538         return H_TOO_HARD;
0539     }
0540 
0541     if (dir != DMA_NONE)
0542         kvmppc_tce_iommu_mapped_dec(kvm, tbl, entry);
0543 
0544     *pua = cpu_to_be64(ua);
0545 
0546     return 0;
0547 }
0548 
0549 static long kvmppc_tce_iommu_map(struct kvm *kvm,
0550         struct kvmppc_spapr_tce_table *stt, struct iommu_table *tbl,
0551         unsigned long entry, unsigned long ua,
0552         enum dma_data_direction dir)
0553 {
0554     unsigned long i, pgoff, ret = H_SUCCESS;
0555     unsigned long subpages = 1ULL << (stt->page_shift - tbl->it_page_shift);
0556     unsigned long io_entry = entry * subpages;
0557 
0558     for (i = 0, pgoff = 0; i < subpages;
0559             ++i, pgoff += IOMMU_PAGE_SIZE(tbl)) {
0560 
0561         ret = kvmppc_tce_iommu_do_map(kvm, tbl,
0562                 io_entry + i, ua + pgoff, dir);
0563         if (ret != H_SUCCESS)
0564             break;
0565     }
0566 
0567     iommu_tce_kill(tbl, io_entry, subpages);
0568 
0569     return ret;
0570 }
0571 
0572 long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
0573               unsigned long ioba, unsigned long tce)
0574 {
0575     struct kvmppc_spapr_tce_table *stt;
0576     long ret, idx;
0577     struct kvmppc_spapr_tce_iommu_table *stit;
0578     unsigned long entry, ua = 0;
0579     enum dma_data_direction dir;
0580 
0581     /* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
0582     /*      liobn, ioba, tce); */
0583 
0584     stt = kvmppc_find_table(vcpu->kvm, liobn);
0585     if (!stt)
0586         return H_TOO_HARD;
0587 
0588     ret = kvmppc_ioba_validate(stt, ioba, 1);
0589     if (ret != H_SUCCESS)
0590         return ret;
0591 
0592     idx = srcu_read_lock(&vcpu->kvm->srcu);
0593 
0594     ret = kvmppc_tce_validate(stt, tce);
0595     if (ret != H_SUCCESS)
0596         goto unlock_exit;
0597 
0598     dir = iommu_tce_direction(tce);
0599 
0600     if ((dir != DMA_NONE) && kvmppc_tce_to_ua(vcpu->kvm, tce, &ua)) {
0601         ret = H_PARAMETER;
0602         goto unlock_exit;
0603     }
0604 
0605     entry = ioba >> stt->page_shift;
0606 
0607     list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
0608         if (dir == DMA_NONE)
0609             ret = kvmppc_tce_iommu_unmap(vcpu->kvm, stt,
0610                     stit->tbl, entry);
0611         else
0612             ret = kvmppc_tce_iommu_map(vcpu->kvm, stt, stit->tbl,
0613                     entry, ua, dir);
0614 
0615 
0616         if (ret != H_SUCCESS) {
0617             kvmppc_clear_tce(vcpu->kvm->mm, stt, stit->tbl, entry);
0618             goto unlock_exit;
0619         }
0620     }
0621 
0622     kvmppc_tce_put(stt, entry, tce);
0623 
0624 unlock_exit:
0625     srcu_read_unlock(&vcpu->kvm->srcu, idx);
0626 
0627     return ret;
0628 }
0629 EXPORT_SYMBOL_GPL(kvmppc_h_put_tce);
0630 
0631 long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
0632         unsigned long liobn, unsigned long ioba,
0633         unsigned long tce_list, unsigned long npages)
0634 {
0635     struct kvmppc_spapr_tce_table *stt;
0636     long i, ret = H_SUCCESS, idx;
0637     unsigned long entry, ua = 0;
0638     u64 __user *tces;
0639     u64 tce;
0640     struct kvmppc_spapr_tce_iommu_table *stit;
0641 
0642     stt = kvmppc_find_table(vcpu->kvm, liobn);
0643     if (!stt)
0644         return H_TOO_HARD;
0645 
0646     entry = ioba >> stt->page_shift;
0647     /*
0648      * SPAPR spec says that the maximum size of the list is 512 TCEs
0649      * so the whole table fits in 4K page
0650      */
0651     if (npages > 512)
0652         return H_PARAMETER;
0653 
0654     if (tce_list & (SZ_4K - 1))
0655         return H_PARAMETER;
0656 
0657     ret = kvmppc_ioba_validate(stt, ioba, npages);
0658     if (ret != H_SUCCESS)
0659         return ret;
0660 
0661     idx = srcu_read_lock(&vcpu->kvm->srcu);
0662     if (kvmppc_tce_to_ua(vcpu->kvm, tce_list, &ua)) {
0663         ret = H_TOO_HARD;
0664         goto unlock_exit;
0665     }
0666     tces = (u64 __user *) ua;
0667 
0668     for (i = 0; i < npages; ++i) {
0669         if (get_user(tce, tces + i)) {
0670             ret = H_TOO_HARD;
0671             goto unlock_exit;
0672         }
0673         tce = be64_to_cpu(tce);
0674 
0675         ret = kvmppc_tce_validate(stt, tce);
0676         if (ret != H_SUCCESS)
0677             goto unlock_exit;
0678     }
0679 
0680     for (i = 0; i < npages; ++i) {
0681         /*
0682          * This looks unsafe, because we validate, then regrab
0683          * the TCE from userspace which could have been changed by
0684          * another thread.
0685          *
0686          * But it actually is safe, because the relevant checks will be
0687          * re-executed in the following code.  If userspace tries to
0688          * change this dodgily it will result in a messier failure mode
0689          * but won't threaten the host.
0690          */
0691         if (get_user(tce, tces + i)) {
0692             ret = H_TOO_HARD;
0693             goto unlock_exit;
0694         }
0695         tce = be64_to_cpu(tce);
0696 
0697         if (kvmppc_tce_to_ua(vcpu->kvm, tce, &ua)) {
0698             ret = H_PARAMETER;
0699             goto unlock_exit;
0700         }
0701 
0702         list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
0703             ret = kvmppc_tce_iommu_map(vcpu->kvm, stt,
0704                     stit->tbl, entry + i, ua,
0705                     iommu_tce_direction(tce));
0706 
0707             if (ret != H_SUCCESS) {
0708                 kvmppc_clear_tce(vcpu->kvm->mm, stt, stit->tbl,
0709                          entry + i);
0710                 goto unlock_exit;
0711             }
0712         }
0713 
0714         kvmppc_tce_put(stt, entry + i, tce);
0715     }
0716 
0717 unlock_exit:
0718     srcu_read_unlock(&vcpu->kvm->srcu, idx);
0719 
0720     return ret;
0721 }
0722 EXPORT_SYMBOL_GPL(kvmppc_h_put_tce_indirect);
0723 
0724 long kvmppc_h_stuff_tce(struct kvm_vcpu *vcpu,
0725         unsigned long liobn, unsigned long ioba,
0726         unsigned long tce_value, unsigned long npages)
0727 {
0728     struct kvmppc_spapr_tce_table *stt;
0729     long i, ret;
0730     struct kvmppc_spapr_tce_iommu_table *stit;
0731 
0732     stt = kvmppc_find_table(vcpu->kvm, liobn);
0733     if (!stt)
0734         return H_TOO_HARD;
0735 
0736     ret = kvmppc_ioba_validate(stt, ioba, npages);
0737     if (ret != H_SUCCESS)
0738         return ret;
0739 
0740     /* Check permission bits only to allow userspace poison TCE for debug */
0741     if (tce_value & (TCE_PCI_WRITE | TCE_PCI_READ))
0742         return H_PARAMETER;
0743 
0744     list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
0745         unsigned long entry = ioba >> stt->page_shift;
0746 
0747         for (i = 0; i < npages; ++i) {
0748             ret = kvmppc_tce_iommu_unmap(vcpu->kvm, stt,
0749                     stit->tbl, entry + i);
0750 
0751             if (ret == H_SUCCESS)
0752                 continue;
0753 
0754             if (ret == H_TOO_HARD)
0755                 return ret;
0756 
0757             WARN_ON_ONCE(1);
0758             kvmppc_clear_tce(vcpu->kvm->mm, stt, stit->tbl, entry + i);
0759         }
0760     }
0761 
0762     for (i = 0; i < npages; ++i, ioba += (1ULL << stt->page_shift))
0763         kvmppc_tce_put(stt, ioba >> stt->page_shift, tce_value);
0764 
0765     return ret;
0766 }
0767 EXPORT_SYMBOL_GPL(kvmppc_h_stuff_tce);
0768 
0769 long kvmppc_h_get_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
0770               unsigned long ioba)
0771 {
0772     struct kvmppc_spapr_tce_table *stt;
0773     long ret;
0774     unsigned long idx;
0775     struct page *page;
0776     u64 *tbl;
0777 
0778     stt = kvmppc_find_table(vcpu->kvm, liobn);
0779     if (!stt)
0780         return H_TOO_HARD;
0781 
0782     ret = kvmppc_ioba_validate(stt, ioba, 1);
0783     if (ret != H_SUCCESS)
0784         return ret;
0785 
0786     idx = (ioba >> stt->page_shift) - stt->offset;
0787     page = stt->pages[idx / TCES_PER_PAGE];
0788     if (!page) {
0789         vcpu->arch.regs.gpr[4] = 0;
0790         return H_SUCCESS;
0791     }
0792     tbl = (u64 *)page_address(page);
0793 
0794     vcpu->arch.regs.gpr[4] = tbl[idx % TCES_PER_PAGE];
0795 
0796     return H_SUCCESS;
0797 }
0798 EXPORT_SYMBOL_GPL(kvmppc_h_get_tce);
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