1c942fddfSThomas Gleixner // SPDX-License-Identifier: GPL-2.0-or-later 2133ff0eaSJérôme Glisse /* 3133ff0eaSJérôme Glisse * Copyright 2013 Red Hat Inc. 4133ff0eaSJérôme Glisse * 5f813f219SJérôme Glisse * Authors: Jérôme Glisse <jglisse@redhat.com> 6133ff0eaSJérôme Glisse */ 7133ff0eaSJérôme Glisse /* 8133ff0eaSJérôme Glisse * Refer to include/linux/hmm.h for information about heterogeneous memory 9133ff0eaSJérôme Glisse * management or HMM for short. 10133ff0eaSJérôme Glisse */ 11a520110eSChristoph Hellwig #include <linux/pagewalk.h> 12133ff0eaSJérôme Glisse #include <linux/hmm.h> 13858b54daSJérôme Glisse #include <linux/init.h> 14da4c3c73SJérôme Glisse #include <linux/rmap.h> 15da4c3c73SJérôme Glisse #include <linux/swap.h> 16133ff0eaSJérôme Glisse #include <linux/slab.h> 17133ff0eaSJérôme Glisse #include <linux/sched.h> 184ef589dcSJérôme Glisse #include <linux/mmzone.h> 194ef589dcSJérôme Glisse #include <linux/pagemap.h> 20da4c3c73SJérôme Glisse #include <linux/swapops.h> 21da4c3c73SJérôme Glisse #include <linux/hugetlb.h> 224ef589dcSJérôme Glisse #include <linux/memremap.h> 23c8a53b2dSJason Gunthorpe #include <linux/sched/mm.h> 247b2d55d2SJérôme Glisse #include <linux/jump_label.h> 2555c0ece8SJérôme Glisse #include <linux/dma-mapping.h> 26c0b12405SJérôme Glisse #include <linux/mmu_notifier.h> 274ef589dcSJérôme Glisse #include <linux/memory_hotplug.h> 284ef589dcSJérôme Glisse 2974eee180SJérôme Glisse struct hmm_vma_walk { 3074eee180SJérôme Glisse struct hmm_range *range; 31992de9a8SJérôme Glisse struct dev_pagemap *pgmap; 3274eee180SJérôme Glisse unsigned long last; 339a4903e4SChristoph Hellwig unsigned int flags; 3474eee180SJérôme Glisse }; 3574eee180SJérôme Glisse 36d28c2c9aSRalph Campbell static int hmm_pfns_fill(unsigned long addr, unsigned long end, 37d28c2c9aSRalph Campbell struct hmm_range *range, enum hmm_pfn_value_e value) 38da4c3c73SJérôme Glisse { 39ff05c0c6SJérôme Glisse uint64_t *pfns = range->pfns; 40da4c3c73SJérôme Glisse unsigned long i; 41da4c3c73SJérôme Glisse 42da4c3c73SJérôme Glisse i = (addr - range->start) >> PAGE_SHIFT; 43da4c3c73SJérôme Glisse for (; addr < end; addr += PAGE_SIZE, i++) 44d28c2c9aSRalph Campbell pfns[i] = range->values[value]; 45da4c3c73SJérôme Glisse 46da4c3c73SJérôme Glisse return 0; 47da4c3c73SJérôme Glisse } 48da4c3c73SJérôme Glisse 495504ed29SJérôme Glisse /* 50f8c888a3SChristoph Hellwig * hmm_vma_fault() - fault in a range lacking valid pmd or pte(s) 51d2e8d551SRalph Campbell * @addr: range virtual start address (inclusive) 525504ed29SJérôme Glisse * @end: range virtual end address (exclusive) 532aee09d8SJérôme Glisse * @fault: should we fault or not ? 542aee09d8SJérôme Glisse * @write_fault: write fault ? 555504ed29SJérôme Glisse * @walk: mm_walk structure 56f8c888a3SChristoph Hellwig * Return: -EBUSY after page fault, or page fault error 575504ed29SJérôme Glisse * 585504ed29SJérôme Glisse * This function will be called whenever pmd_none() or pte_none() returns true, 595504ed29SJérôme Glisse * or whenever there is no page directory covering the virtual address range. 605504ed29SJérôme Glisse */ 61f8c888a3SChristoph Hellwig static int hmm_vma_fault(unsigned long addr, unsigned long end, 622aee09d8SJérôme Glisse bool fault, bool write_fault, 63da4c3c73SJérôme Glisse struct mm_walk *walk) 64da4c3c73SJérôme Glisse { 6574eee180SJérôme Glisse struct hmm_vma_walk *hmm_vma_walk = walk->private; 6674eee180SJérôme Glisse struct hmm_range *range = hmm_vma_walk->range; 675a0c38d3SChristoph Hellwig struct vm_area_struct *vma = walk->vma; 68ff05c0c6SJérôme Glisse uint64_t *pfns = range->pfns; 69f8c888a3SChristoph Hellwig unsigned long i = (addr - range->start) >> PAGE_SHIFT; 705a0c38d3SChristoph Hellwig unsigned int fault_flags = FAULT_FLAG_REMOTE; 71da4c3c73SJérôme Glisse 72f8c888a3SChristoph Hellwig WARN_ON_ONCE(!fault && !write_fault); 7374eee180SJérôme Glisse hmm_vma_walk->last = addr; 7463d5066fSJérôme Glisse 755a0c38d3SChristoph Hellwig if (!vma) 765a0c38d3SChristoph Hellwig goto out_error; 775a0c38d3SChristoph Hellwig 785a0c38d3SChristoph Hellwig if (write_fault) { 795a0c38d3SChristoph Hellwig if (!(vma->vm_flags & VM_WRITE)) 80c18ce674SRalph Campbell return -EPERM; 815a0c38d3SChristoph Hellwig fault_flags |= FAULT_FLAG_WRITE; 8274eee180SJérôme Glisse } 8374eee180SJérôme Glisse 845a0c38d3SChristoph Hellwig for (; addr < end; addr += PAGE_SIZE, i++) 855a0c38d3SChristoph Hellwig if (handle_mm_fault(vma, addr, fault_flags) & VM_FAULT_ERROR) 865a0c38d3SChristoph Hellwig goto out_error; 875a0c38d3SChristoph Hellwig 88f8c888a3SChristoph Hellwig return -EBUSY; 895a0c38d3SChristoph Hellwig 905a0c38d3SChristoph Hellwig out_error: 915a0c38d3SChristoph Hellwig pfns[i] = range->values[HMM_PFN_ERROR]; 925a0c38d3SChristoph Hellwig return -EFAULT; 932aee09d8SJérôme Glisse } 942aee09d8SJérôme Glisse 952aee09d8SJérôme Glisse static inline void hmm_pte_need_fault(const struct hmm_vma_walk *hmm_vma_walk, 962aee09d8SJérôme Glisse uint64_t pfns, uint64_t cpu_flags, 972aee09d8SJérôme Glisse bool *fault, bool *write_fault) 982aee09d8SJérôme Glisse { 99f88a1e90SJérôme Glisse struct hmm_range *range = hmm_vma_walk->range; 100f88a1e90SJérôme Glisse 101d45d464bSChristoph Hellwig if (hmm_vma_walk->flags & HMM_FAULT_SNAPSHOT) 1022aee09d8SJérôme Glisse return; 1032aee09d8SJérôme Glisse 104023a019aSJérôme Glisse /* 105023a019aSJérôme Glisse * So we not only consider the individual per page request we also 106023a019aSJérôme Glisse * consider the default flags requested for the range. The API can 107d2e8d551SRalph Campbell * be used 2 ways. The first one where the HMM user coalesces 108d2e8d551SRalph Campbell * multiple page faults into one request and sets flags per pfn for 109d2e8d551SRalph Campbell * those faults. The second one where the HMM user wants to pre- 110023a019aSJérôme Glisse * fault a range with specific flags. For the latter one it is a 111023a019aSJérôme Glisse * waste to have the user pre-fill the pfn arrays with a default 112023a019aSJérôme Glisse * flags value. 113023a019aSJérôme Glisse */ 114023a019aSJérôme Glisse pfns = (pfns & range->pfn_flags_mask) | range->default_flags; 115023a019aSJérôme Glisse 1162aee09d8SJérôme Glisse /* We aren't ask to do anything ... */ 117f88a1e90SJérôme Glisse if (!(pfns & range->flags[HMM_PFN_VALID])) 1182aee09d8SJérôme Glisse return; 119f88a1e90SJérôme Glisse 120f88a1e90SJérôme Glisse /* If CPU page table is not valid then we need to fault */ 121f88a1e90SJérôme Glisse *fault = !(cpu_flags & range->flags[HMM_PFN_VALID]); 122f88a1e90SJérôme Glisse /* Need to write fault ? */ 123f88a1e90SJérôme Glisse if ((pfns & range->flags[HMM_PFN_WRITE]) && 124f88a1e90SJérôme Glisse !(cpu_flags & range->flags[HMM_PFN_WRITE])) { 125f88a1e90SJérôme Glisse *write_fault = true; 1262aee09d8SJérôme Glisse *fault = true; 1272aee09d8SJérôme Glisse } 1282aee09d8SJérôme Glisse } 1292aee09d8SJérôme Glisse 1302aee09d8SJérôme Glisse static void hmm_range_need_fault(const struct hmm_vma_walk *hmm_vma_walk, 1312aee09d8SJérôme Glisse const uint64_t *pfns, unsigned long npages, 1322aee09d8SJérôme Glisse uint64_t cpu_flags, bool *fault, 1332aee09d8SJérôme Glisse bool *write_fault) 1342aee09d8SJérôme Glisse { 1352aee09d8SJérôme Glisse unsigned long i; 1362aee09d8SJérôme Glisse 137d45d464bSChristoph Hellwig if (hmm_vma_walk->flags & HMM_FAULT_SNAPSHOT) { 1382aee09d8SJérôme Glisse *fault = *write_fault = false; 1392aee09d8SJérôme Glisse return; 1402aee09d8SJérôme Glisse } 1412aee09d8SJérôme Glisse 142a3e0d41cSJérôme Glisse *fault = *write_fault = false; 1432aee09d8SJérôme Glisse for (i = 0; i < npages; ++i) { 1442aee09d8SJérôme Glisse hmm_pte_need_fault(hmm_vma_walk, pfns[i], cpu_flags, 1452aee09d8SJérôme Glisse fault, write_fault); 146a3e0d41cSJérôme Glisse if ((*write_fault)) 1472aee09d8SJérôme Glisse return; 1482aee09d8SJérôme Glisse } 1492aee09d8SJérôme Glisse } 1502aee09d8SJérôme Glisse 1512aee09d8SJérôme Glisse static int hmm_vma_walk_hole(unsigned long addr, unsigned long end, 152b7a16c7aSSteven Price __always_unused int depth, struct mm_walk *walk) 1532aee09d8SJérôme Glisse { 1542aee09d8SJérôme Glisse struct hmm_vma_walk *hmm_vma_walk = walk->private; 1552aee09d8SJérôme Glisse struct hmm_range *range = hmm_vma_walk->range; 1562aee09d8SJérôme Glisse bool fault, write_fault; 1572aee09d8SJérôme Glisse unsigned long i, npages; 1582aee09d8SJérôme Glisse uint64_t *pfns; 1592aee09d8SJérôme Glisse 1602aee09d8SJérôme Glisse i = (addr - range->start) >> PAGE_SHIFT; 1612aee09d8SJérôme Glisse npages = (end - addr) >> PAGE_SHIFT; 1622aee09d8SJérôme Glisse pfns = &range->pfns[i]; 1632aee09d8SJérôme Glisse hmm_range_need_fault(hmm_vma_walk, pfns, npages, 1642aee09d8SJérôme Glisse 0, &fault, &write_fault); 165f8c888a3SChristoph Hellwig if (fault || write_fault) 166f8c888a3SChristoph Hellwig return hmm_vma_fault(addr, end, fault, write_fault, walk); 167f8c888a3SChristoph Hellwig hmm_vma_walk->last = addr; 168f8c888a3SChristoph Hellwig return hmm_pfns_fill(addr, end, range, HMM_PFN_NONE); 1692aee09d8SJérôme Glisse } 1702aee09d8SJérôme Glisse 171f88a1e90SJérôme Glisse static inline uint64_t pmd_to_hmm_pfn_flags(struct hmm_range *range, pmd_t pmd) 1722aee09d8SJérôme Glisse { 1732aee09d8SJérôme Glisse if (pmd_protnone(pmd)) 1742aee09d8SJérôme Glisse return 0; 175f88a1e90SJérôme Glisse return pmd_write(pmd) ? range->flags[HMM_PFN_VALID] | 176f88a1e90SJérôme Glisse range->flags[HMM_PFN_WRITE] : 177f88a1e90SJérôme Glisse range->flags[HMM_PFN_VALID]; 178da4c3c73SJérôme Glisse } 179da4c3c73SJérôme Glisse 180992de9a8SJérôme Glisse #ifdef CONFIG_TRANSPARENT_HUGEPAGE 1819d3973d6SChristoph Hellwig static int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr, 1829d3973d6SChristoph Hellwig unsigned long end, uint64_t *pfns, pmd_t pmd) 1839d3973d6SChristoph Hellwig { 18453f5c3f4SJérôme Glisse struct hmm_vma_walk *hmm_vma_walk = walk->private; 185f88a1e90SJérôme Glisse struct hmm_range *range = hmm_vma_walk->range; 1862aee09d8SJérôme Glisse unsigned long pfn, npages, i; 1872aee09d8SJérôme Glisse bool fault, write_fault; 188f88a1e90SJérôme Glisse uint64_t cpu_flags; 18953f5c3f4SJérôme Glisse 1902aee09d8SJérôme Glisse npages = (end - addr) >> PAGE_SHIFT; 191f88a1e90SJérôme Glisse cpu_flags = pmd_to_hmm_pfn_flags(range, pmd); 1922aee09d8SJérôme Glisse hmm_range_need_fault(hmm_vma_walk, pfns, npages, cpu_flags, 1932aee09d8SJérôme Glisse &fault, &write_fault); 19453f5c3f4SJérôme Glisse 19524cee8abSJason Gunthorpe if (fault || write_fault) 196f8c888a3SChristoph Hellwig return hmm_vma_fault(addr, end, fault, write_fault, walk); 19753f5c3f4SJérôme Glisse 198309f9a4fSChristoph Hellwig pfn = pmd_pfn(pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT); 199992de9a8SJérôme Glisse for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++) { 200992de9a8SJérôme Glisse if (pmd_devmap(pmd)) { 201992de9a8SJérôme Glisse hmm_vma_walk->pgmap = get_dev_pagemap(pfn, 202992de9a8SJérôme Glisse hmm_vma_walk->pgmap); 203992de9a8SJérôme Glisse if (unlikely(!hmm_vma_walk->pgmap)) 204992de9a8SJérôme Glisse return -EBUSY; 205992de9a8SJérôme Glisse } 206391aab11SJérôme Glisse pfns[i] = hmm_device_entry_from_pfn(range, pfn) | cpu_flags; 207992de9a8SJérôme Glisse } 208992de9a8SJérôme Glisse if (hmm_vma_walk->pgmap) { 209992de9a8SJérôme Glisse put_dev_pagemap(hmm_vma_walk->pgmap); 210992de9a8SJérôme Glisse hmm_vma_walk->pgmap = NULL; 211992de9a8SJérôme Glisse } 21253f5c3f4SJérôme Glisse hmm_vma_walk->last = end; 21353f5c3f4SJérôme Glisse return 0; 21453f5c3f4SJérôme Glisse } 2159d3973d6SChristoph Hellwig #else /* CONFIG_TRANSPARENT_HUGEPAGE */ 2169d3973d6SChristoph Hellwig /* stub to allow the code below to compile */ 2179d3973d6SChristoph Hellwig int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr, 2189d3973d6SChristoph Hellwig unsigned long end, uint64_t *pfns, pmd_t pmd); 2199d3973d6SChristoph Hellwig #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 22053f5c3f4SJérôme Glisse 221f88a1e90SJérôme Glisse static inline uint64_t pte_to_hmm_pfn_flags(struct hmm_range *range, pte_t pte) 2222aee09d8SJérôme Glisse { 223789c2af8SPhilip Yang if (pte_none(pte) || !pte_present(pte) || pte_protnone(pte)) 2242aee09d8SJérôme Glisse return 0; 225f88a1e90SJérôme Glisse return pte_write(pte) ? range->flags[HMM_PFN_VALID] | 226f88a1e90SJérôme Glisse range->flags[HMM_PFN_WRITE] : 227f88a1e90SJérôme Glisse range->flags[HMM_PFN_VALID]; 2282aee09d8SJérôme Glisse } 2292aee09d8SJérôme Glisse 23053f5c3f4SJérôme Glisse static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr, 23153f5c3f4SJérôme Glisse unsigned long end, pmd_t *pmdp, pte_t *ptep, 23253f5c3f4SJérôme Glisse uint64_t *pfn) 23353f5c3f4SJérôme Glisse { 23453f5c3f4SJérôme Glisse struct hmm_vma_walk *hmm_vma_walk = walk->private; 235f88a1e90SJérôme Glisse struct hmm_range *range = hmm_vma_walk->range; 2362aee09d8SJérôme Glisse bool fault, write_fault; 2372aee09d8SJérôme Glisse uint64_t cpu_flags; 23853f5c3f4SJérôme Glisse pte_t pte = *ptep; 239f88a1e90SJérôme Glisse uint64_t orig_pfn = *pfn; 24053f5c3f4SJérôme Glisse 241f88a1e90SJérôme Glisse *pfn = range->values[HMM_PFN_NONE]; 24273231612SJérôme Glisse fault = write_fault = false; 24353f5c3f4SJérôme Glisse 24453f5c3f4SJérôme Glisse if (pte_none(pte)) { 24573231612SJérôme Glisse hmm_pte_need_fault(hmm_vma_walk, orig_pfn, 0, 24673231612SJérôme Glisse &fault, &write_fault); 2472aee09d8SJérôme Glisse if (fault || write_fault) 24853f5c3f4SJérôme Glisse goto fault; 24953f5c3f4SJérôme Glisse return 0; 25053f5c3f4SJérôme Glisse } 25153f5c3f4SJérôme Glisse 25253f5c3f4SJérôme Glisse if (!pte_present(pte)) { 25353f5c3f4SJérôme Glisse swp_entry_t entry = pte_to_swp_entry(pte); 25453f5c3f4SJérôme Glisse 25553f5c3f4SJérôme Glisse /* 256*17ffdc48SChristoph Hellwig * Never fault in device private pages pages, but just report 257*17ffdc48SChristoph Hellwig * the PFN even if not present. 25853f5c3f4SJérôme Glisse */ 25953f5c3f4SJérôme Glisse if (is_device_private_entry(entry)) { 260391aab11SJérôme Glisse *pfn = hmm_device_entry_from_pfn(range, 261391aab11SJérôme Glisse swp_offset(entry)); 262*17ffdc48SChristoph Hellwig *pfn |= range->flags[HMM_PFN_VALID]; 263*17ffdc48SChristoph Hellwig if (is_write_device_private_entry(entry)) 264*17ffdc48SChristoph Hellwig *pfn |= range->flags[HMM_PFN_WRITE]; 26553f5c3f4SJérôme Glisse return 0; 26653f5c3f4SJérôme Glisse } 26753f5c3f4SJérôme Glisse 26876612d6cSJason Gunthorpe hmm_pte_need_fault(hmm_vma_walk, orig_pfn, 0, &fault, 26976612d6cSJason Gunthorpe &write_fault); 27076612d6cSJason Gunthorpe if (!fault && !write_fault) 27176612d6cSJason Gunthorpe return 0; 27276612d6cSJason Gunthorpe 27376612d6cSJason Gunthorpe if (!non_swap_entry(entry)) 27476612d6cSJason Gunthorpe goto fault; 27576612d6cSJason Gunthorpe 27653f5c3f4SJérôme Glisse if (is_migration_entry(entry)) { 27753f5c3f4SJérôme Glisse pte_unmap(ptep); 27853f5c3f4SJérôme Glisse hmm_vma_walk->last = addr; 279d2e8d551SRalph Campbell migration_entry_wait(walk->mm, pmdp, addr); 28073231612SJérôme Glisse return -EBUSY; 28153f5c3f4SJérôme Glisse } 28253f5c3f4SJérôme Glisse 28353f5c3f4SJérôme Glisse /* Report error for everything else */ 284dfdc2207SJason Gunthorpe pte_unmap(ptep); 285f88a1e90SJérôme Glisse *pfn = range->values[HMM_PFN_ERROR]; 28653f5c3f4SJérôme Glisse return -EFAULT; 28753f5c3f4SJérôme Glisse } 28853f5c3f4SJérôme Glisse 28976612d6cSJason Gunthorpe cpu_flags = pte_to_hmm_pfn_flags(range, pte); 29076612d6cSJason Gunthorpe hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags, &fault, 29176612d6cSJason Gunthorpe &write_fault); 2922aee09d8SJérôme Glisse if (fault || write_fault) 29353f5c3f4SJérôme Glisse goto fault; 29453f5c3f4SJérôme Glisse 295992de9a8SJérôme Glisse if (pte_devmap(pte)) { 296992de9a8SJérôme Glisse hmm_vma_walk->pgmap = get_dev_pagemap(pte_pfn(pte), 297992de9a8SJérôme Glisse hmm_vma_walk->pgmap); 298dfdc2207SJason Gunthorpe if (unlikely(!hmm_vma_walk->pgmap)) { 299dfdc2207SJason Gunthorpe pte_unmap(ptep); 300992de9a8SJérôme Glisse return -EBUSY; 301dfdc2207SJason Gunthorpe } 30240550627SJason Gunthorpe } 30340550627SJason Gunthorpe 30440550627SJason Gunthorpe /* 30540550627SJason Gunthorpe * Since each architecture defines a struct page for the zero page, just 30640550627SJason Gunthorpe * fall through and treat it like a normal page. 30740550627SJason Gunthorpe */ 30840550627SJason Gunthorpe if (pte_special(pte) && !is_zero_pfn(pte_pfn(pte))) { 30940550627SJason Gunthorpe hmm_pte_need_fault(hmm_vma_walk, orig_pfn, 0, &fault, 31040550627SJason Gunthorpe &write_fault); 31140550627SJason Gunthorpe if (fault || write_fault) { 312dfdc2207SJason Gunthorpe pte_unmap(ptep); 313992de9a8SJérôme Glisse return -EFAULT; 314992de9a8SJérôme Glisse } 31540550627SJason Gunthorpe *pfn = range->values[HMM_PFN_SPECIAL]; 31640550627SJason Gunthorpe return 0; 317ac541f25SRalph Campbell } 318992de9a8SJérôme Glisse 319391aab11SJérôme Glisse *pfn = hmm_device_entry_from_pfn(range, pte_pfn(pte)) | cpu_flags; 32053f5c3f4SJérôme Glisse return 0; 32153f5c3f4SJérôme Glisse 32253f5c3f4SJérôme Glisse fault: 323992de9a8SJérôme Glisse if (hmm_vma_walk->pgmap) { 324992de9a8SJérôme Glisse put_dev_pagemap(hmm_vma_walk->pgmap); 325992de9a8SJérôme Glisse hmm_vma_walk->pgmap = NULL; 326992de9a8SJérôme Glisse } 32753f5c3f4SJérôme Glisse pte_unmap(ptep); 32853f5c3f4SJérôme Glisse /* Fault any virtual address we were asked to fault */ 329f8c888a3SChristoph Hellwig return hmm_vma_fault(addr, end, fault, write_fault, walk); 33053f5c3f4SJérôme Glisse } 33153f5c3f4SJérôme Glisse 332da4c3c73SJérôme Glisse static int hmm_vma_walk_pmd(pmd_t *pmdp, 333da4c3c73SJérôme Glisse unsigned long start, 334da4c3c73SJérôme Glisse unsigned long end, 335da4c3c73SJérôme Glisse struct mm_walk *walk) 336da4c3c73SJérôme Glisse { 33774eee180SJérôme Glisse struct hmm_vma_walk *hmm_vma_walk = walk->private; 33874eee180SJérôme Glisse struct hmm_range *range = hmm_vma_walk->range; 3392288a9a6SJason Gunthorpe uint64_t *pfns = &range->pfns[(start - range->start) >> PAGE_SHIFT]; 3402288a9a6SJason Gunthorpe unsigned long npages = (end - start) >> PAGE_SHIFT; 3412288a9a6SJason Gunthorpe unsigned long addr = start; 3422288a9a6SJason Gunthorpe bool fault, write_fault; 343da4c3c73SJérôme Glisse pte_t *ptep; 344da4c3c73SJérôme Glisse pmd_t pmd; 345da4c3c73SJérôme Glisse 346d08faca0SJérôme Glisse again: 347d08faca0SJérôme Glisse pmd = READ_ONCE(*pmdp); 348d08faca0SJérôme Glisse if (pmd_none(pmd)) 349b7a16c7aSSteven Price return hmm_vma_walk_hole(start, end, -1, walk); 350d08faca0SJérôme Glisse 351d08faca0SJérôme Glisse if (thp_migration_supported() && is_pmd_migration_entry(pmd)) { 352d08faca0SJérôme Glisse hmm_range_need_fault(hmm_vma_walk, pfns, npages, 353d08faca0SJérôme Glisse 0, &fault, &write_fault); 354d08faca0SJérôme Glisse if (fault || write_fault) { 355d08faca0SJérôme Glisse hmm_vma_walk->last = addr; 356d2e8d551SRalph Campbell pmd_migration_entry_wait(walk->mm, pmdp); 35773231612SJérôme Glisse return -EBUSY; 358d08faca0SJérôme Glisse } 3597d082987SJason Gunthorpe return hmm_pfns_fill(start, end, range, HMM_PFN_NONE); 3602288a9a6SJason Gunthorpe } 3612288a9a6SJason Gunthorpe 3622288a9a6SJason Gunthorpe if (!pmd_present(pmd)) { 3632288a9a6SJason Gunthorpe hmm_range_need_fault(hmm_vma_walk, pfns, npages, 0, &fault, 3642288a9a6SJason Gunthorpe &write_fault); 3652288a9a6SJason Gunthorpe if (fault || write_fault) 3662288a9a6SJason Gunthorpe return -EFAULT; 367d28c2c9aSRalph Campbell return hmm_pfns_fill(start, end, range, HMM_PFN_ERROR); 3682288a9a6SJason Gunthorpe } 369d08faca0SJérôme Glisse 370d08faca0SJérôme Glisse if (pmd_devmap(pmd) || pmd_trans_huge(pmd)) { 371da4c3c73SJérôme Glisse /* 372d2e8d551SRalph Campbell * No need to take pmd_lock here, even if some other thread 373da4c3c73SJérôme Glisse * is splitting the huge pmd we will get that event through 374da4c3c73SJérôme Glisse * mmu_notifier callback. 375da4c3c73SJérôme Glisse * 376d2e8d551SRalph Campbell * So just read pmd value and check again it's a transparent 377da4c3c73SJérôme Glisse * huge or device mapping one and compute corresponding pfn 378da4c3c73SJérôme Glisse * values. 379da4c3c73SJérôme Glisse */ 380da4c3c73SJérôme Glisse pmd = pmd_read_atomic(pmdp); 381da4c3c73SJérôme Glisse barrier(); 382da4c3c73SJérôme Glisse if (!pmd_devmap(pmd) && !pmd_trans_huge(pmd)) 383da4c3c73SJérôme Glisse goto again; 384da4c3c73SJérôme Glisse 3852288a9a6SJason Gunthorpe return hmm_vma_handle_pmd(walk, addr, end, pfns, pmd); 386da4c3c73SJérôme Glisse } 387da4c3c73SJérôme Glisse 388d08faca0SJérôme Glisse /* 389d2e8d551SRalph Campbell * We have handled all the valid cases above ie either none, migration, 390d08faca0SJérôme Glisse * huge or transparent huge. At this point either it is a valid pmd 391d08faca0SJérôme Glisse * entry pointing to pte directory or it is a bad pmd that will not 392d08faca0SJérôme Glisse * recover. 393d08faca0SJérôme Glisse */ 3942288a9a6SJason Gunthorpe if (pmd_bad(pmd)) { 3952288a9a6SJason Gunthorpe hmm_range_need_fault(hmm_vma_walk, pfns, npages, 0, &fault, 3962288a9a6SJason Gunthorpe &write_fault); 3972288a9a6SJason Gunthorpe if (fault || write_fault) 3982288a9a6SJason Gunthorpe return -EFAULT; 399d28c2c9aSRalph Campbell return hmm_pfns_fill(start, end, range, HMM_PFN_ERROR); 4002288a9a6SJason Gunthorpe } 401da4c3c73SJérôme Glisse 402da4c3c73SJérôme Glisse ptep = pte_offset_map(pmdp, addr); 4032288a9a6SJason Gunthorpe for (; addr < end; addr += PAGE_SIZE, ptep++, pfns++) { 40453f5c3f4SJérôme Glisse int r; 405da4c3c73SJérôme Glisse 4062288a9a6SJason Gunthorpe r = hmm_vma_handle_pte(walk, addr, end, pmdp, ptep, pfns); 40753f5c3f4SJérôme Glisse if (r) { 408dfdc2207SJason Gunthorpe /* hmm_vma_handle_pte() did pte_unmap() */ 40974eee180SJérôme Glisse hmm_vma_walk->last = addr; 41053f5c3f4SJérôme Glisse return r; 41174eee180SJérôme Glisse } 412da4c3c73SJérôme Glisse } 413992de9a8SJérôme Glisse if (hmm_vma_walk->pgmap) { 414992de9a8SJérôme Glisse /* 415992de9a8SJérôme Glisse * We do put_dev_pagemap() here and not in hmm_vma_handle_pte() 416992de9a8SJérôme Glisse * so that we can leverage get_dev_pagemap() optimization which 417992de9a8SJérôme Glisse * will not re-take a reference on a pgmap if we already have 418992de9a8SJérôme Glisse * one. 419992de9a8SJérôme Glisse */ 420992de9a8SJérôme Glisse put_dev_pagemap(hmm_vma_walk->pgmap); 421992de9a8SJérôme Glisse hmm_vma_walk->pgmap = NULL; 422992de9a8SJérôme Glisse } 423da4c3c73SJérôme Glisse pte_unmap(ptep - 1); 424da4c3c73SJérôme Glisse 42553f5c3f4SJérôme Glisse hmm_vma_walk->last = addr; 426da4c3c73SJérôme Glisse return 0; 427da4c3c73SJérôme Glisse } 428da4c3c73SJérôme Glisse 429f0b3c45cSChristoph Hellwig #if defined(CONFIG_ARCH_HAS_PTE_DEVMAP) && \ 430f0b3c45cSChristoph Hellwig defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) 431f0b3c45cSChristoph Hellwig static inline uint64_t pud_to_hmm_pfn_flags(struct hmm_range *range, pud_t pud) 432f0b3c45cSChristoph Hellwig { 433f0b3c45cSChristoph Hellwig if (!pud_present(pud)) 434f0b3c45cSChristoph Hellwig return 0; 435f0b3c45cSChristoph Hellwig return pud_write(pud) ? range->flags[HMM_PFN_VALID] | 436f0b3c45cSChristoph Hellwig range->flags[HMM_PFN_WRITE] : 437f0b3c45cSChristoph Hellwig range->flags[HMM_PFN_VALID]; 438f0b3c45cSChristoph Hellwig } 439f0b3c45cSChristoph Hellwig 440f0b3c45cSChristoph Hellwig static int hmm_vma_walk_pud(pud_t *pudp, unsigned long start, unsigned long end, 441992de9a8SJérôme Glisse struct mm_walk *walk) 442992de9a8SJérôme Glisse { 443992de9a8SJérôme Glisse struct hmm_vma_walk *hmm_vma_walk = walk->private; 444992de9a8SJérôme Glisse struct hmm_range *range = hmm_vma_walk->range; 4453afc4236SSteven Price unsigned long addr = start; 446992de9a8SJérôme Glisse pud_t pud; 4473afc4236SSteven Price int ret = 0; 4483afc4236SSteven Price spinlock_t *ptl = pud_trans_huge_lock(pudp, walk->vma); 449992de9a8SJérôme Glisse 4503afc4236SSteven Price if (!ptl) 4513afc4236SSteven Price return 0; 4523afc4236SSteven Price 4533afc4236SSteven Price /* Normally we don't want to split the huge page */ 4543afc4236SSteven Price walk->action = ACTION_CONTINUE; 4553afc4236SSteven Price 456992de9a8SJérôme Glisse pud = READ_ONCE(*pudp); 4573afc4236SSteven Price if (pud_none(pud)) { 45805fc1df9SJason Gunthorpe spin_unlock(ptl); 45905fc1df9SJason Gunthorpe return hmm_vma_walk_hole(start, end, -1, walk); 4603afc4236SSteven Price } 461992de9a8SJérôme Glisse 462992de9a8SJérôme Glisse if (pud_huge(pud) && pud_devmap(pud)) { 463992de9a8SJérôme Glisse unsigned long i, npages, pfn; 464992de9a8SJérôme Glisse uint64_t *pfns, cpu_flags; 465992de9a8SJérôme Glisse bool fault, write_fault; 466992de9a8SJérôme Glisse 4673afc4236SSteven Price if (!pud_present(pud)) { 46805fc1df9SJason Gunthorpe spin_unlock(ptl); 46905fc1df9SJason Gunthorpe return hmm_vma_walk_hole(start, end, -1, walk); 4703afc4236SSteven Price } 471992de9a8SJérôme Glisse 472992de9a8SJérôme Glisse i = (addr - range->start) >> PAGE_SHIFT; 473992de9a8SJérôme Glisse npages = (end - addr) >> PAGE_SHIFT; 474992de9a8SJérôme Glisse pfns = &range->pfns[i]; 475992de9a8SJérôme Glisse 476992de9a8SJérôme Glisse cpu_flags = pud_to_hmm_pfn_flags(range, pud); 477992de9a8SJérôme Glisse hmm_range_need_fault(hmm_vma_walk, pfns, npages, 478992de9a8SJérôme Glisse cpu_flags, &fault, &write_fault); 4793afc4236SSteven Price if (fault || write_fault) { 48005fc1df9SJason Gunthorpe spin_unlock(ptl); 481f8c888a3SChristoph Hellwig return hmm_vma_fault(addr, end, fault, write_fault, 48205fc1df9SJason Gunthorpe walk); 4833afc4236SSteven Price } 484992de9a8SJérôme Glisse 485992de9a8SJérôme Glisse pfn = pud_pfn(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT); 486992de9a8SJérôme Glisse for (i = 0; i < npages; ++i, ++pfn) { 487992de9a8SJérôme Glisse hmm_vma_walk->pgmap = get_dev_pagemap(pfn, 488992de9a8SJérôme Glisse hmm_vma_walk->pgmap); 4893afc4236SSteven Price if (unlikely(!hmm_vma_walk->pgmap)) { 4903afc4236SSteven Price ret = -EBUSY; 4913afc4236SSteven Price goto out_unlock; 4923afc4236SSteven Price } 493391aab11SJérôme Glisse pfns[i] = hmm_device_entry_from_pfn(range, pfn) | 494391aab11SJérôme Glisse cpu_flags; 495992de9a8SJérôme Glisse } 496992de9a8SJérôme Glisse if (hmm_vma_walk->pgmap) { 497992de9a8SJérôme Glisse put_dev_pagemap(hmm_vma_walk->pgmap); 498992de9a8SJérôme Glisse hmm_vma_walk->pgmap = NULL; 499992de9a8SJérôme Glisse } 500992de9a8SJérôme Glisse hmm_vma_walk->last = end; 5013afc4236SSteven Price goto out_unlock; 502992de9a8SJérôme Glisse } 503992de9a8SJérôme Glisse 5043afc4236SSteven Price /* Ask for the PUD to be split */ 5053afc4236SSteven Price walk->action = ACTION_SUBTREE; 506992de9a8SJérôme Glisse 5073afc4236SSteven Price out_unlock: 5083afc4236SSteven Price spin_unlock(ptl); 509992de9a8SJérôme Glisse return ret; 510992de9a8SJérôme Glisse } 511f0b3c45cSChristoph Hellwig #else 512f0b3c45cSChristoph Hellwig #define hmm_vma_walk_pud NULL 513f0b3c45cSChristoph Hellwig #endif 514992de9a8SJérôme Glisse 515251bbe59SChristoph Hellwig #ifdef CONFIG_HUGETLB_PAGE 51663d5066fSJérôme Glisse static int hmm_vma_walk_hugetlb_entry(pte_t *pte, unsigned long hmask, 51763d5066fSJérôme Glisse unsigned long start, unsigned long end, 51863d5066fSJérôme Glisse struct mm_walk *walk) 51963d5066fSJérôme Glisse { 52005c23af4SChristoph Hellwig unsigned long addr = start, i, pfn; 52163d5066fSJérôme Glisse struct hmm_vma_walk *hmm_vma_walk = walk->private; 52263d5066fSJérôme Glisse struct hmm_range *range = hmm_vma_walk->range; 52363d5066fSJérôme Glisse struct vm_area_struct *vma = walk->vma; 52463d5066fSJérôme Glisse uint64_t orig_pfn, cpu_flags; 52563d5066fSJérôme Glisse bool fault, write_fault; 52663d5066fSJérôme Glisse spinlock_t *ptl; 52763d5066fSJérôme Glisse pte_t entry; 52863d5066fSJérôme Glisse 529d2e8d551SRalph Campbell ptl = huge_pte_lock(hstate_vma(vma), walk->mm, pte); 53063d5066fSJérôme Glisse entry = huge_ptep_get(pte); 53163d5066fSJérôme Glisse 5327f08263dSChristoph Hellwig i = (start - range->start) >> PAGE_SHIFT; 53363d5066fSJérôme Glisse orig_pfn = range->pfns[i]; 53463d5066fSJérôme Glisse range->pfns[i] = range->values[HMM_PFN_NONE]; 53563d5066fSJérôme Glisse cpu_flags = pte_to_hmm_pfn_flags(range, entry); 53663d5066fSJérôme Glisse fault = write_fault = false; 53763d5066fSJérôme Glisse hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags, 53863d5066fSJérôme Glisse &fault, &write_fault); 53963d5066fSJérôme Glisse if (fault || write_fault) { 54045050692SChristoph Hellwig spin_unlock(ptl); 541f8c888a3SChristoph Hellwig return hmm_vma_fault(addr, end, fault, write_fault, walk); 54263d5066fSJérôme Glisse } 54363d5066fSJérôme Glisse 54405c23af4SChristoph Hellwig pfn = pte_pfn(entry) + ((start & ~hmask) >> PAGE_SHIFT); 5457f08263dSChristoph Hellwig for (; addr < end; addr += PAGE_SIZE, i++, pfn++) 546391aab11SJérôme Glisse range->pfns[i] = hmm_device_entry_from_pfn(range, pfn) | 547391aab11SJérôme Glisse cpu_flags; 54863d5066fSJérôme Glisse hmm_vma_walk->last = end; 54963d5066fSJérôme Glisse spin_unlock(ptl); 55045050692SChristoph Hellwig return 0; 55163d5066fSJérôme Glisse } 552251bbe59SChristoph Hellwig #else 553251bbe59SChristoph Hellwig #define hmm_vma_walk_hugetlb_entry NULL 554251bbe59SChristoph Hellwig #endif /* CONFIG_HUGETLB_PAGE */ 55563d5066fSJérôme Glisse 556d28c2c9aSRalph Campbell static int hmm_vma_walk_test(unsigned long start, unsigned long end, 557d28c2c9aSRalph Campbell struct mm_walk *walk) 55833cd47dcSJérôme Glisse { 559d28c2c9aSRalph Campbell struct hmm_vma_walk *hmm_vma_walk = walk->private; 560d28c2c9aSRalph Campbell struct hmm_range *range = hmm_vma_walk->range; 561d28c2c9aSRalph Campbell struct vm_area_struct *vma = walk->vma; 562d28c2c9aSRalph Campbell 563d28c2c9aSRalph Campbell /* 564c2579c9cSJason Gunthorpe * Skip vma ranges that don't have struct page backing them or map I/O 565c2579c9cSJason Gunthorpe * devices directly. 566c2579c9cSJason Gunthorpe * 567d28c2c9aSRalph Campbell * If the vma does not allow read access, then assume that it does not 568c2579c9cSJason Gunthorpe * allow write access either. HMM does not support architectures that 569c2579c9cSJason Gunthorpe * allow write without read. 570d28c2c9aSRalph Campbell */ 571c2579c9cSJason Gunthorpe if ((vma->vm_flags & (VM_IO | VM_PFNMAP | VM_MIXEDMAP)) || 572c2579c9cSJason Gunthorpe !(vma->vm_flags & VM_READ)) { 573d28c2c9aSRalph Campbell bool fault, write_fault; 574d28c2c9aSRalph Campbell 575d28c2c9aSRalph Campbell /* 576d28c2c9aSRalph Campbell * Check to see if a fault is requested for any page in the 577d28c2c9aSRalph Campbell * range. 578d28c2c9aSRalph Campbell */ 579d28c2c9aSRalph Campbell hmm_range_need_fault(hmm_vma_walk, range->pfns + 580d28c2c9aSRalph Campbell ((start - range->start) >> PAGE_SHIFT), 581d28c2c9aSRalph Campbell (end - start) >> PAGE_SHIFT, 582d28c2c9aSRalph Campbell 0, &fault, &write_fault); 583d28c2c9aSRalph Campbell if (fault || write_fault) 584d28c2c9aSRalph Campbell return -EFAULT; 585d28c2c9aSRalph Campbell 586c2579c9cSJason Gunthorpe hmm_pfns_fill(start, end, range, HMM_PFN_ERROR); 587d28c2c9aSRalph Campbell hmm_vma_walk->last = end; 588d28c2c9aSRalph Campbell 589d28c2c9aSRalph Campbell /* Skip this vma and continue processing the next vma. */ 590d28c2c9aSRalph Campbell return 1; 591d28c2c9aSRalph Campbell } 592d28c2c9aSRalph Campbell 593d28c2c9aSRalph Campbell return 0; 59433cd47dcSJérôme Glisse } 59533cd47dcSJérôme Glisse 5967b86ac33SChristoph Hellwig static const struct mm_walk_ops hmm_walk_ops = { 5977b86ac33SChristoph Hellwig .pud_entry = hmm_vma_walk_pud, 5987b86ac33SChristoph Hellwig .pmd_entry = hmm_vma_walk_pmd, 5997b86ac33SChristoph Hellwig .pte_hole = hmm_vma_walk_hole, 6007b86ac33SChristoph Hellwig .hugetlb_entry = hmm_vma_walk_hugetlb_entry, 601d28c2c9aSRalph Campbell .test_walk = hmm_vma_walk_test, 6027b86ac33SChristoph Hellwig }; 6037b86ac33SChristoph Hellwig 6049a4903e4SChristoph Hellwig /** 6059a4903e4SChristoph Hellwig * hmm_range_fault - try to fault some address in a virtual address range 60608232a45SJérôme Glisse * @range: range being faulted 6079a4903e4SChristoph Hellwig * @flags: HMM_FAULT_* flags 60873231612SJérôme Glisse * 6099a4903e4SChristoph Hellwig * Return: the number of valid pages in range->pfns[] (from range start 6109a4903e4SChristoph Hellwig * address), which may be zero. On error one of the following status codes 6119a4903e4SChristoph Hellwig * can be returned: 6129a4903e4SChristoph Hellwig * 6139a4903e4SChristoph Hellwig * -EINVAL: Invalid arguments or mm or virtual address is in an invalid vma 6149a4903e4SChristoph Hellwig * (e.g., device file vma). 61573231612SJérôme Glisse * -ENOMEM: Out of memory. 6169a4903e4SChristoph Hellwig * -EPERM: Invalid permission (e.g., asking for write and range is read 6179a4903e4SChristoph Hellwig * only). 6189a4903e4SChristoph Hellwig * -EBUSY: The range has been invalidated and the caller needs to wait for 6199a4903e4SChristoph Hellwig * the invalidation to finish. 6209a4903e4SChristoph Hellwig * -EFAULT: Invalid (i.e., either no valid vma or it is illegal to access 6219a4903e4SChristoph Hellwig * that range) number of valid pages in range->pfns[] (from 62273231612SJérôme Glisse * range start address). 62374eee180SJérôme Glisse * 62474eee180SJérôme Glisse * This is similar to a regular CPU page fault except that it will not trigger 62573231612SJérôme Glisse * any memory migration if the memory being faulted is not accessible by CPUs 62673231612SJérôme Glisse * and caller does not ask for migration. 62774eee180SJérôme Glisse * 628ff05c0c6SJérôme Glisse * On error, for one virtual address in the range, the function will mark the 629ff05c0c6SJérôme Glisse * corresponding HMM pfn entry with an error flag. 63074eee180SJérôme Glisse */ 6319a4903e4SChristoph Hellwig long hmm_range_fault(struct hmm_range *range, unsigned int flags) 63274eee180SJérôme Glisse { 633d28c2c9aSRalph Campbell struct hmm_vma_walk hmm_vma_walk = { 634d28c2c9aSRalph Campbell .range = range, 635d28c2c9aSRalph Campbell .last = range->start, 636d28c2c9aSRalph Campbell .flags = flags, 637d28c2c9aSRalph Campbell }; 638a22dd506SJason Gunthorpe struct mm_struct *mm = range->notifier->mm; 63974eee180SJérôme Glisse int ret; 64074eee180SJérôme Glisse 64104ec32fbSJason Gunthorpe lockdep_assert_held(&mm->mmap_sem); 642a3e0d41cSJérôme Glisse 643a3e0d41cSJérôme Glisse do { 644a3e0d41cSJérôme Glisse /* If range is no longer valid force retry. */ 645a22dd506SJason Gunthorpe if (mmu_interval_check_retry(range->notifier, 646a22dd506SJason Gunthorpe range->notifier_seq)) 6472bcbeaefSChristoph Hellwig return -EBUSY; 648d28c2c9aSRalph Campbell ret = walk_page_range(mm, hmm_vma_walk.last, range->end, 6497b86ac33SChristoph Hellwig &hmm_walk_ops, &hmm_vma_walk); 650d28c2c9aSRalph Campbell } while (ret == -EBUSY); 651a3e0d41cSJérôme Glisse 652d28c2c9aSRalph Campbell if (ret) 65373231612SJérôme Glisse return ret; 65473231612SJérôme Glisse return (hmm_vma_walk.last - range->start) >> PAGE_SHIFT; 65574eee180SJérôme Glisse } 65673231612SJérôme Glisse EXPORT_SYMBOL(hmm_range_fault); 657