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Linux/arch/powerpc/kvm/book3s_64_mmu_hv.c

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  1 // SPDX-License-Identifier: GPL-2.0-only
  2 /*
  3  *
  4  * Copyright 2010 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
  5  */
  6 
  7 #include <linux/types.h>
  8 #include <linux/string.h>
  9 #include <linux/kvm.h>
 10 #include <linux/kvm_host.h>
 11 #include <linux/highmem.h>
 12 #include <linux/gfp.h>
 13 #include <linux/slab.h>
 14 #include <linux/hugetlb.h>
 15 #include <linux/vmalloc.h>
 16 #include <linux/srcu.h>
 17 #include <linux/anon_inodes.h>
 18 #include <linux/file.h>
 19 #include <linux/debugfs.h>
 20 
 21 #include <asm/kvm_ppc.h>
 22 #include <asm/kvm_book3s.h>
 23 #include <asm/book3s/64/mmu-hash.h>
 24 #include <asm/hvcall.h>
 25 #include <asm/synch.h>
 26 #include <asm/ppc-opcode.h>
 27 #include <asm/cputable.h>
 28 #include <asm/pte-walk.h>
 29 
 30 #include "trace_hv.h"
 31 
 32 //#define DEBUG_RESIZE_HPT      1
 33 
 34 #ifdef DEBUG_RESIZE_HPT
 35 #define resize_hpt_debug(resize, ...)                           \
 36         do {                                                    \
 37                 printk(KERN_DEBUG "RESIZE HPT %p: ", resize);   \
 38                 printk(__VA_ARGS__);                            \
 39         } while (0)
 40 #else
 41 #define resize_hpt_debug(resize, ...)                           \
 42         do { } while (0)
 43 #endif
 44 
 45 static long kvmppc_virtmode_do_h_enter(struct kvm *kvm, unsigned long flags,
 46                                 long pte_index, unsigned long pteh,
 47                                 unsigned long ptel, unsigned long *pte_idx_ret);
 48 
 49 struct kvm_resize_hpt {
 50         /* These fields read-only after init */
 51         struct kvm *kvm;
 52         struct work_struct work;
 53         u32 order;
 54 
 55         /* These fields protected by kvm->arch.mmu_setup_lock */
 56 
 57         /* Possible values and their usage:
 58          *  <0     an error occurred during allocation,
 59          *  -EBUSY allocation is in the progress,
 60          *  0      allocation made successfuly.
 61          */
 62         int error;
 63 
 64         /* Private to the work thread, until error != -EBUSY,
 65          * then protected by kvm->arch.mmu_setup_lock.
 66          */
 67         struct kvm_hpt_info hpt;
 68 };
 69 
 70 int kvmppc_allocate_hpt(struct kvm_hpt_info *info, u32 order)
 71 {
 72         unsigned long hpt = 0;
 73         int cma = 0;
 74         struct page *page = NULL;
 75         struct revmap_entry *rev;
 76         unsigned long npte;
 77 
 78         if ((order < PPC_MIN_HPT_ORDER) || (order > PPC_MAX_HPT_ORDER))
 79                 return -EINVAL;
 80 
 81         page = kvm_alloc_hpt_cma(1ul << (order - PAGE_SHIFT));
 82         if (page) {
 83                 hpt = (unsigned long)pfn_to_kaddr(page_to_pfn(page));
 84                 memset((void *)hpt, 0, (1ul << order));
 85                 cma = 1;
 86         }
 87 
 88         if (!hpt)
 89                 hpt = __get_free_pages(GFP_KERNEL|__GFP_ZERO|__GFP_RETRY_MAYFAIL
 90                                        |__GFP_NOWARN, order - PAGE_SHIFT);
 91 
 92         if (!hpt)
 93                 return -ENOMEM;
 94 
 95         /* HPTEs are 2**4 bytes long */
 96         npte = 1ul << (order - 4);
 97 
 98         /* Allocate reverse map array */
 99         rev = vmalloc(array_size(npte, sizeof(struct revmap_entry)));
100         if (!rev) {
101                 if (cma)
102                         kvm_free_hpt_cma(page, 1 << (order - PAGE_SHIFT));
103                 else
104                         free_pages(hpt, order - PAGE_SHIFT);
105                 return -ENOMEM;
106         }
107 
108         info->order = order;
109         info->virt = hpt;
110         info->cma = cma;
111         info->rev = rev;
112 
113         return 0;
114 }
115 
116 void kvmppc_set_hpt(struct kvm *kvm, struct kvm_hpt_info *info)
117 {
118         atomic64_set(&kvm->arch.mmio_update, 0);
119         kvm->arch.hpt = *info;
120         kvm->arch.sdr1 = __pa(info->virt) | (info->order - 18);
121 
122         pr_debug("KVM guest htab at %lx (order %ld), LPID %x\n",
123                  info->virt, (long)info->order, kvm->arch.lpid);
124 }
125 
126 long kvmppc_alloc_reset_hpt(struct kvm *kvm, int order)
127 {
128         long err = -EBUSY;
129         struct kvm_hpt_info info;
130 
131         mutex_lock(&kvm->arch.mmu_setup_lock);
132         if (kvm->arch.mmu_ready) {
133                 kvm->arch.mmu_ready = 0;
134                 /* order mmu_ready vs. vcpus_running */
135                 smp_mb();
136                 if (atomic_read(&kvm->arch.vcpus_running)) {
137                         kvm->arch.mmu_ready = 1;
138                         goto out;
139                 }
140         }
141         if (kvm_is_radix(kvm)) {
142                 err = kvmppc_switch_mmu_to_hpt(kvm);
143                 if (err)
144                         goto out;
145         }
146 
147         if (kvm->arch.hpt.order == order) {
148                 /* We already have a suitable HPT */
149 
150                 /* Set the entire HPT to 0, i.e. invalid HPTEs */
151                 memset((void *)kvm->arch.hpt.virt, 0, 1ul << order);
152                 /*
153                  * Reset all the reverse-mapping chains for all memslots
154                  */
155                 kvmppc_rmap_reset(kvm);
156                 err = 0;
157                 goto out;
158         }
159 
160         if (kvm->arch.hpt.virt) {
161                 kvmppc_free_hpt(&kvm->arch.hpt);
162                 kvmppc_rmap_reset(kvm);
163         }
164 
165         err = kvmppc_allocate_hpt(&info, order);
166         if (err < 0)
167                 goto out;
168         kvmppc_set_hpt(kvm, &info);
169 
170 out:
171         if (err == 0)
172                 /* Ensure that each vcpu will flush its TLB on next entry. */
173                 cpumask_setall(&kvm->arch.need_tlb_flush);
174 
175         mutex_unlock(&kvm->arch.mmu_setup_lock);
176         return err;
177 }
178 
179 void kvmppc_free_hpt(struct kvm_hpt_info *info)
180 {
181         vfree(info->rev);
182         info->rev = NULL;
183         if (info->cma)
184                 kvm_free_hpt_cma(virt_to_page(info->virt),
185                                  1 << (info->order - PAGE_SHIFT));
186         else if (info->virt)
187                 free_pages(info->virt, info->order - PAGE_SHIFT);
188         info->virt = 0;
189         info->order = 0;
190 }
191 
192 /* Bits in first HPTE dword for pagesize 4k, 64k or 16M */
193 static inline unsigned long hpte0_pgsize_encoding(unsigned long pgsize)
194 {
195         return (pgsize > 0x1000) ? HPTE_V_LARGE : 0;
196 }
197 
198 /* Bits in second HPTE dword for pagesize 4k, 64k or 16M */
199 static inline unsigned long hpte1_pgsize_encoding(unsigned long pgsize)
200 {
201         return (pgsize == 0x10000) ? 0x1000 : 0;
202 }
203 
204 void kvmppc_map_vrma(struct kvm_vcpu *vcpu, struct kvm_memory_slot *memslot,
205                      unsigned long porder)
206 {
207         unsigned long i;
208         unsigned long npages;
209         unsigned long hp_v, hp_r;
210         unsigned long addr, hash;
211         unsigned long psize;
212         unsigned long hp0, hp1;
213         unsigned long idx_ret;
214         long ret;
215         struct kvm *kvm = vcpu->kvm;
216 
217         psize = 1ul << porder;
218         npages = memslot->npages >> (porder - PAGE_SHIFT);
219 
220         /* VRMA can't be > 1TB */
221         if (npages > 1ul << (40 - porder))
222                 npages = 1ul << (40 - porder);
223         /* Can't use more than 1 HPTE per HPTEG */
224         if (npages > kvmppc_hpt_mask(&kvm->arch.hpt) + 1)
225                 npages = kvmppc_hpt_mask(&kvm->arch.hpt) + 1;
226 
227         hp0 = HPTE_V_1TB_SEG | (VRMA_VSID << (40 - 16)) |
228                 HPTE_V_BOLTED | hpte0_pgsize_encoding(psize);
229         hp1 = hpte1_pgsize_encoding(psize) |
230                 HPTE_R_R | HPTE_R_C | HPTE_R_M | PP_RWXX;
231 
232         for (i = 0; i < npages; ++i) {
233                 addr = i << porder;
234                 /* can't use hpt_hash since va > 64 bits */
235                 hash = (i ^ (VRMA_VSID ^ (VRMA_VSID << 25)))
236                         & kvmppc_hpt_mask(&kvm->arch.hpt);
237                 /*
238                  * We assume that the hash table is empty and no
239                  * vcpus are using it at this stage.  Since we create
240                  * at most one HPTE per HPTEG, we just assume entry 7
241                  * is available and use it.
242                  */
243                 hash = (hash << 3) + 7;
244                 hp_v = hp0 | ((addr >> 16) & ~0x7fUL);
245                 hp_r = hp1 | addr;
246                 ret = kvmppc_virtmode_do_h_enter(kvm, H_EXACT, hash, hp_v, hp_r,
247                                                  &idx_ret);
248                 if (ret != H_SUCCESS) {
249                         pr_err("KVM: map_vrma at %lx failed, ret=%ld\n",
250                                addr, ret);
251                         break;
252                 }
253         }
254 }
255 
256 int kvmppc_mmu_hv_init(void)
257 {
258         unsigned long host_lpid, rsvd_lpid;
259 
260         if (!mmu_has_feature(MMU_FTR_LOCKLESS_TLBIE))
261                 return -EINVAL;
262 
263         /* POWER7 has 10-bit LPIDs (12-bit in POWER8) */
264         host_lpid = 0;
265         if (cpu_has_feature(CPU_FTR_HVMODE))
266                 host_lpid = mfspr(SPRN_LPID);
267         rsvd_lpid = LPID_RSVD;
268 
269         kvmppc_init_lpid(rsvd_lpid + 1);
270 
271         kvmppc_claim_lpid(host_lpid);
272         /* rsvd_lpid is reserved for use in partition switching */
273         kvmppc_claim_lpid(rsvd_lpid);
274 
275         return 0;
276 }
277 
278 static long kvmppc_virtmode_do_h_enter(struct kvm *kvm, unsigned long flags,
279                                 long pte_index, unsigned long pteh,
280                                 unsigned long ptel, unsigned long *pte_idx_ret)
281 {
282         long ret;
283 
284         /* Protect linux PTE lookup from page table destruction */
285         rcu_read_lock_sched();  /* this disables preemption too */
286         ret = kvmppc_do_h_enter(kvm, flags, pte_index, pteh, ptel,
287                                 kvm->mm->pgd, false, pte_idx_ret);
288         rcu_read_unlock_sched();
289         if (ret == H_TOO_HARD) {
290                 /* this can't happen */
291                 pr_err("KVM: Oops, kvmppc_h_enter returned too hard!\n");
292                 ret = H_RESOURCE;       /* or something */
293         }
294         return ret;
295 
296 }
297 
298 static struct kvmppc_slb *kvmppc_mmu_book3s_hv_find_slbe(struct kvm_vcpu *vcpu,
299                                                          gva_t eaddr)
300 {
301         u64 mask;
302         int i;
303 
304         for (i = 0; i < vcpu->arch.slb_nr; i++) {
305                 if (!(vcpu->arch.slb[i].orige & SLB_ESID_V))
306                         continue;
307 
308                 if (vcpu->arch.slb[i].origv & SLB_VSID_B_1T)
309                         mask = ESID_MASK_1T;
310                 else
311                         mask = ESID_MASK;
312 
313                 if (((vcpu->arch.slb[i].orige ^ eaddr) & mask) == 0)
314                         return &vcpu->arch.slb[i];
315         }
316         return NULL;
317 }
318 
319 static unsigned long kvmppc_mmu_get_real_addr(unsigned long v, unsigned long r,
320                         unsigned long ea)
321 {
322         unsigned long ra_mask;
323 
324         ra_mask = kvmppc_actual_pgsz(v, r) - 1;
325         return (r & HPTE_R_RPN & ~ra_mask) | (ea & ra_mask);
326 }
327 
328 static int kvmppc_mmu_book3s_64_hv_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
329                         struct kvmppc_pte *gpte, bool data, bool iswrite)
330 {
331         struct kvm *kvm = vcpu->kvm;
332         struct kvmppc_slb *slbe;
333         unsigned long slb_v;
334         unsigned long pp, key;
335         unsigned long v, orig_v, gr;
336         __be64 *hptep;
337         long int index;
338         int virtmode = vcpu->arch.shregs.msr & (data ? MSR_DR : MSR_IR);
339 
340         if (kvm_is_radix(vcpu->kvm))
341                 return kvmppc_mmu_radix_xlate(vcpu, eaddr, gpte, data, iswrite);
342 
343         /* Get SLB entry */
344         if (virtmode) {
345                 slbe = kvmppc_mmu_book3s_hv_find_slbe(vcpu, eaddr);
346                 if (!slbe)
347                         return -EINVAL;
348                 slb_v = slbe->origv;
349         } else {
350                 /* real mode access */
351                 slb_v = vcpu->kvm->arch.vrma_slb_v;
352         }
353 
354         preempt_disable();
355         /* Find the HPTE in the hash table */
356         index = kvmppc_hv_find_lock_hpte(kvm, eaddr, slb_v,
357                                          HPTE_V_VALID | HPTE_V_ABSENT);
358         if (index < 0) {
359                 preempt_enable();
360                 return -ENOENT;
361         }
362         hptep = (__be64 *)(kvm->arch.hpt.virt + (index << 4));
363         v = orig_v = be64_to_cpu(hptep[0]) & ~HPTE_V_HVLOCK;
364         if (cpu_has_feature(CPU_FTR_ARCH_300))
365                 v = hpte_new_to_old_v(v, be64_to_cpu(hptep[1]));
366         gr = kvm->arch.hpt.rev[index].guest_rpte;
367 
368         unlock_hpte(hptep, orig_v);
369         preempt_enable();
370 
371         gpte->eaddr = eaddr;
372         gpte->vpage = ((v & HPTE_V_AVPN) << 4) | ((eaddr >> 12) & 0xfff);
373 
374         /* Get PP bits and key for permission check */
375         pp = gr & (HPTE_R_PP0 | HPTE_R_PP);
376         key = (vcpu->arch.shregs.msr & MSR_PR) ? SLB_VSID_KP : SLB_VSID_KS;
377         key &= slb_v;
378 
379         /* Calculate permissions */
380         gpte->may_read = hpte_read_permission(pp, key);
381         gpte->may_write = hpte_write_permission(pp, key);
382         gpte->may_execute = gpte->may_read && !(gr & (HPTE_R_N | HPTE_R_G));
383 
384         /* Storage key permission check for POWER7 */
385         if (data && virtmode) {
386                 int amrfield = hpte_get_skey_perm(gr, vcpu->arch.amr);
387                 if (amrfield & 1)
388                         gpte->may_read = 0;
389                 if (amrfield & 2)
390                         gpte->may_write = 0;
391         }
392 
393         /* Get the guest physical address */
394         gpte->raddr = kvmppc_mmu_get_real_addr(v, gr, eaddr);
395         return 0;
396 }
397 
398 /*
399  * Quick test for whether an instruction is a load or a store.
400  * If the instruction is a load or a store, then this will indicate
401  * which it is, at least on server processors.  (Embedded processors
402  * have some external PID instructions that don't follow the rule
403  * embodied here.)  If the instruction isn't a load or store, then
404  * this doesn't return anything useful.
405  */
406 static int instruction_is_store(unsigned int instr)
407 {
408         unsigned int mask;
409 
410         mask = 0x10000000;
411         if ((instr & 0xfc000000) == 0x7c000000)
412                 mask = 0x100;           /* major opcode 31 */
413         return (instr & mask) != 0;
414 }
415 
416 int kvmppc_hv_emulate_mmio(struct kvm_run *run, struct kvm_vcpu *vcpu,
417                            unsigned long gpa, gva_t ea, int is_store)
418 {
419         u32 last_inst;
420 
421         /*
422          * Fast path - check if the guest physical address corresponds to a
423          * device on the FAST_MMIO_BUS, if so we can avoid loading the
424          * instruction all together, then we can just handle it and return.
425          */
426         if (is_store) {
427                 int idx, ret;
428 
429                 idx = srcu_read_lock(&vcpu->kvm->srcu);
430                 ret = kvm_io_bus_write(vcpu, KVM_FAST_MMIO_BUS, (gpa_t) gpa, 0,
431                                        NULL);
432                 srcu_read_unlock(&vcpu->kvm->srcu, idx);
433                 if (!ret) {
434                         kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
435                         return RESUME_GUEST;
436                 }
437         }
438 
439         /*
440          * If we fail, we just return to the guest and try executing it again.
441          */
442         if (kvmppc_get_last_inst(vcpu, INST_GENERIC, &last_inst) !=
443                 EMULATE_DONE)
444                 return RESUME_GUEST;
445 
446         /*
447          * WARNING: We do not know for sure whether the instruction we just
448          * read from memory is the same that caused the fault in the first
449          * place.  If the instruction we read is neither an load or a store,
450          * then it can't access memory, so we don't need to worry about
451          * enforcing access permissions.  So, assuming it is a load or
452          * store, we just check that its direction (load or store) is
453          * consistent with the original fault, since that's what we
454          * checked the access permissions against.  If there is a mismatch
455          * we just return and retry the instruction.
456          */
457 
458         if (instruction_is_store(last_inst) != !!is_store)
459                 return RESUME_GUEST;
460 
461         /*
462          * Emulated accesses are emulated by looking at the hash for
463          * translation once, then performing the access later. The
464          * translation could be invalidated in the meantime in which
465          * point performing the subsequent memory access on the old
466          * physical address could possibly be a security hole for the
467          * guest (but not the host).
468          *
469          * This is less of an issue for MMIO stores since they aren't
470          * globally visible. It could be an issue for MMIO loads to
471          * a certain extent but we'll ignore it for now.
472          */
473 
474         vcpu->arch.paddr_accessed = gpa;
475         vcpu->arch.vaddr_accessed = ea;
476         return kvmppc_emulate_mmio(run, vcpu);
477 }
478 
479 int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
480                                 unsigned long ea, unsigned long dsisr)
481 {
482         struct kvm *kvm = vcpu->kvm;
483         unsigned long hpte[3], r;
484         unsigned long hnow_v, hnow_r;
485         __be64 *hptep;
486         unsigned long mmu_seq, psize, pte_size;
487         unsigned long gpa_base, gfn_base;
488         unsigned long gpa, gfn, hva, pfn;
489         struct kvm_memory_slot *memslot;
490         unsigned long *rmap;
491         struct revmap_entry *rev;
492         struct page *page, *pages[1];
493         long index, ret, npages;
494         bool is_ci;
495         unsigned int writing, write_ok;
496         struct vm_area_struct *vma;
497         unsigned long rcbits;
498         long mmio_update;
499         struct mm_struct *mm;
500 
501         if (kvm_is_radix(kvm))
502                 return kvmppc_book3s_radix_page_fault(run, vcpu, ea, dsisr);
503 
504         /*
505          * Real-mode code has already searched the HPT and found the
506          * entry we're interested in.  Lock the entry and check that
507          * it hasn't changed.  If it has, just return and re-execute the
508          * instruction.
509          */
510         if (ea != vcpu->arch.pgfault_addr)
511                 return RESUME_GUEST;
512 
513         if (vcpu->arch.pgfault_cache) {
514                 mmio_update = atomic64_read(&kvm->arch.mmio_update);
515                 if (mmio_update == vcpu->arch.pgfault_cache->mmio_update) {
516                         r = vcpu->arch.pgfault_cache->rpte;
517                         psize = kvmppc_actual_pgsz(vcpu->arch.pgfault_hpte[0],
518                                                    r);
519                         gpa_base = r & HPTE_R_RPN & ~(psize - 1);
520                         gfn_base = gpa_base >> PAGE_SHIFT;
521                         gpa = gpa_base | (ea & (psize - 1));
522                         return kvmppc_hv_emulate_mmio(run, vcpu, gpa, ea,
523                                                 dsisr & DSISR_ISSTORE);
524                 }
525         }
526         index = vcpu->arch.pgfault_index;
527         hptep = (__be64 *)(kvm->arch.hpt.virt + (index << 4));
528         rev = &kvm->arch.hpt.rev[index];
529         preempt_disable();
530         while (!try_lock_hpte(hptep, HPTE_V_HVLOCK))
531                 cpu_relax();
532         hpte[0] = be64_to_cpu(hptep[0]) & ~HPTE_V_HVLOCK;
533         hpte[1] = be64_to_cpu(hptep[1]);
534         hpte[2] = r = rev->guest_rpte;
535         unlock_hpte(hptep, hpte[0]);
536         preempt_enable();
537 
538         if (cpu_has_feature(CPU_FTR_ARCH_300)) {
539                 hpte[0] = hpte_new_to_old_v(hpte[0], hpte[1]);
540                 hpte[1] = hpte_new_to_old_r(hpte[1]);
541         }
542         if (hpte[0] != vcpu->arch.pgfault_hpte[0] ||
543             hpte[1] != vcpu->arch.pgfault_hpte[1])
544                 return RESUME_GUEST;
545 
546         /* Translate the logical address and get the page */
547         psize = kvmppc_actual_pgsz(hpte[0], r);
548         gpa_base = r & HPTE_R_RPN & ~(psize - 1);
549         gfn_base = gpa_base >> PAGE_SHIFT;
550         gpa = gpa_base | (ea & (psize - 1));
551         gfn = gpa >> PAGE_SHIFT;
552         memslot = gfn_to_memslot(kvm, gfn);
553 
554         trace_kvm_page_fault_enter(vcpu, hpte, memslot, ea, dsisr);
555 
556         /* No memslot means it's an emulated MMIO region */
557         if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID))
558                 return kvmppc_hv_emulate_mmio(run, vcpu, gpa, ea,
559                                               dsisr & DSISR_ISSTORE);
560 
561         /*
562          * This should never happen, because of the slot_is_aligned()
563          * check in kvmppc_do_h_enter().
564          */
565         if (gfn_base < memslot->base_gfn)
566                 return -EFAULT;
567 
568         /* used to check for invalidations in progress */
569         mmu_seq = kvm->mmu_notifier_seq;
570         smp_rmb();
571 
572         ret = -EFAULT;
573         is_ci = false;
574         pfn = 0;
575         page = NULL;
576         mm = kvm->mm;
577         pte_size = PAGE_SIZE;
578         writing = (dsisr & DSISR_ISSTORE) != 0;
579         /* If writing != 0, then the HPTE must allow writing, if we get here */
580         write_ok = writing;
581         hva = gfn_to_hva_memslot(memslot, gfn);
582         npages = get_user_pages_fast(hva, 1, writing ? FOLL_WRITE : 0, pages);
583         if (npages < 1) {
584                 /* Check if it's an I/O mapping */
585                 down_read(&mm->mmap_sem);
586                 vma = find_vma(mm, hva);
587                 if (vma && vma->vm_start <= hva && hva + psize <= vma->vm_end &&
588                     (vma->vm_flags & VM_PFNMAP)) {
589                         pfn = vma->vm_pgoff +
590                                 ((hva - vma->vm_start) >> PAGE_SHIFT);
591                         pte_size = psize;
592                         is_ci = pte_ci(__pte((pgprot_val(vma->vm_page_prot))));
593                         write_ok = vma->vm_flags & VM_WRITE;
594                 }
595                 up_read(&mm->mmap_sem);
596                 if (!pfn)
597                         goto out_put;
598         } else {
599                 page = pages[0];
600                 pfn = page_to_pfn(page);
601                 if (PageHuge(page)) {
602                         page = compound_head(page);
603                         pte_size <<= compound_order(page);
604                 }
605                 /* if the guest wants write access, see if that is OK */
606                 if (!writing && hpte_is_writable(r)) {
607                         pte_t *ptep, pte;
608                         unsigned long flags;
609                         /*
610                          * We need to protect against page table destruction
611                          * hugepage split and collapse.
612                          */
613                         local_irq_save(flags);
614                         ptep = find_current_mm_pte(mm->pgd, hva, NULL, NULL);
615                         if (ptep) {
616                                 pte = kvmppc_read_update_linux_pte(ptep, 1);
617                                 if (__pte_write(pte))
618                                         write_ok = 1;
619                         }
620                         local_irq_restore(flags);
621                 }
622         }
623 
624         if (psize > pte_size)
625                 goto out_put;
626 
627         /* Check WIMG vs. the actual page we're accessing */
628         if (!hpte_cache_flags_ok(r, is_ci)) {
629                 if (is_ci)
630                         goto out_put;
631                 /*
632                  * Allow guest to map emulated device memory as
633                  * uncacheable, but actually make it cacheable.
634                  */
635                 r = (r & ~(HPTE_R_W|HPTE_R_I|HPTE_R_G)) | HPTE_R_M;
636         }
637 
638         /*
639          * Set the HPTE to point to pfn.
640          * Since the pfn is at PAGE_SIZE granularity, make sure we
641          * don't mask out lower-order bits if psize < PAGE_SIZE.
642          */
643         if (psize < PAGE_SIZE)
644                 psize = PAGE_SIZE;
645         r = (r & HPTE_R_KEY_HI) | (r & ~(HPTE_R_PP0 - psize)) |
646                                         ((pfn << PAGE_SHIFT) & ~(psize - 1));
647         if (hpte_is_writable(r) && !write_ok)
648                 r = hpte_make_readonly(r);
649         ret = RESUME_GUEST;
650         preempt_disable();
651         while (!try_lock_hpte(hptep, HPTE_V_HVLOCK))
652                 cpu_relax();
653         hnow_v = be64_to_cpu(hptep[0]);
654         hnow_r = be64_to_cpu(hptep[1]);
655         if (cpu_has_feature(CPU_FTR_ARCH_300)) {
656                 hnow_v = hpte_new_to_old_v(hnow_v, hnow_r);
657                 hnow_r = hpte_new_to_old_r(hnow_r);
658         }
659 
660         /*
661          * If the HPT is being resized, don't update the HPTE,
662          * instead let the guest retry after the resize operation is complete.
663          * The synchronization for mmu_ready test vs. set is provided
664          * by the HPTE lock.
665          */
666         if (!kvm->arch.mmu_ready)
667                 goto out_unlock;
668 
669         if ((hnow_v & ~HPTE_V_HVLOCK) != hpte[0] || hnow_r != hpte[1] ||
670             rev->guest_rpte != hpte[2])
671                 /* HPTE has been changed under us; let the guest retry */
672                 goto out_unlock;
673         hpte[0] = (hpte[0] & ~HPTE_V_ABSENT) | HPTE_V_VALID;
674 
675         /* Always put the HPTE in the rmap chain for the page base address */
676         rmap = &memslot->arch.rmap[gfn_base - memslot->base_gfn];
677         lock_rmap(rmap);
678 
679         /* Check if we might have been invalidated; let the guest retry if so */
680         ret = RESUME_GUEST;
681         if (mmu_notifier_retry(vcpu->kvm, mmu_seq)) {
682                 unlock_rmap(rmap);
683                 goto out_unlock;
684         }
685 
686         /* Only set R/C in real HPTE if set in both *rmap and guest_rpte */
687         rcbits = *rmap >> KVMPPC_RMAP_RC_SHIFT;
688         r &= rcbits | ~(HPTE_R_R | HPTE_R_C);
689 
690         if (be64_to_cpu(hptep[0]) & HPTE_V_VALID) {
691                 /* HPTE was previously valid, so we need to invalidate it */
692                 unlock_rmap(rmap);
693                 hptep[0] |= cpu_to_be64(HPTE_V_ABSENT);
694                 kvmppc_invalidate_hpte(kvm, hptep, index);
695                 /* don't lose previous R and C bits */
696                 r |= be64_to_cpu(hptep[1]) & (HPTE_R_R | HPTE_R_C);
697         } else {
698                 kvmppc_add_revmap_chain(kvm, rev, rmap, index, 0);
699         }
700 
701         if (cpu_has_feature(CPU_FTR_ARCH_300)) {
702                 r = hpte_old_to_new_r(hpte[0], r);
703                 hpte[0] = hpte_old_to_new_v(hpte[0]);
704         }
705         hptep[1] = cpu_to_be64(r);
706         eieio();
707         __unlock_hpte(hptep, hpte[0]);
708         asm volatile("ptesync" : : : "memory");
709         preempt_enable();
710         if (page && hpte_is_writable(r))
711                 SetPageDirty(page);
712 
713  out_put:
714         trace_kvm_page_fault_exit(vcpu, hpte, ret);
715 
716         if (page) {
717                 /*
718                  * We drop pages[0] here, not page because page might
719                  * have been set to the head page of a compound, but
720                  * we have to drop the reference on the correct tail
721                  * page to match the get inside gup()
722                  */
723                 put_page(pages[0]);
724         }
725         return ret;
726 
727  out_unlock:
728         __unlock_hpte(hptep, be64_to_cpu(hptep[0]));
729         preempt_enable();
730         goto out_put;
731 }
732 
733 void kvmppc_rmap_reset(struct kvm *kvm)
734 {
735         struct kvm_memslots *slots;
736         struct kvm_memory_slot *memslot;
737         int srcu_idx;
738 
739         srcu_idx = srcu_read_lock(&kvm->srcu);
740         slots = kvm_memslots(kvm);
741         kvm_for_each_memslot(memslot, slots) {
742                 /* Mutual exclusion with kvm_unmap_hva_range etc. */
743                 spin_lock(&kvm->mmu_lock);
744                 /*
745                  * This assumes it is acceptable to lose reference and
746                  * change bits across a reset.
747                  */
748                 memset(memslot->arch.rmap, 0,
749                        memslot->npages * sizeof(*memslot->arch.rmap));
750                 spin_unlock(&kvm->mmu_lock);
751         }
752         srcu_read_unlock(&kvm->srcu, srcu_idx);
753 }
754 
755 typedef int (*hva_handler_fn)(struct kvm *kvm, struct kvm_memory_slot *memslot,
756                               unsigned long gfn);
757 
758 static int kvm_handle_hva_range(struct kvm *kvm,
759                                 unsigned long start,
760                                 unsigned long end,
761                                 hva_handler_fn handler)
762 {
763         int ret;
764         int retval = 0;
765         struct kvm_memslots *slots;
766         struct kvm_memory_slot *memslot;
767 
768         slots = kvm_memslots(kvm);
769         kvm_for_each_memslot(memslot, slots) {
770                 unsigned long hva_start, hva_end;
771                 gfn_t gfn, gfn_end;
772 
773                 hva_start = max(start, memslot->userspace_addr);
774                 hva_end = min(end, memslot->userspace_addr +
775                                         (memslot->npages << PAGE_SHIFT));
776                 if (hva_start >= hva_end)
777                         continue;
778                 /*
779                  * {gfn(page) | page intersects with [hva_start, hva_end)} =
780                  * {gfn, gfn+1, ..., gfn_end-1}.
781                  */
782                 gfn = hva_to_gfn_memslot(hva_start, memslot);
783                 gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot);
784 
785                 for (; gfn < gfn_end; ++gfn) {
786                         ret = handler(kvm, memslot, gfn);
787                         retval |= ret;
788                 }
789         }
790 
791         return retval;
792 }
793 
794 static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
795                           hva_handler_fn handler)
796 {
797         return kvm_handle_hva_range(kvm, hva, hva + 1, handler);
798 }
799 
800 /* Must be called with both HPTE and rmap locked */
801 static void kvmppc_unmap_hpte(struct kvm *kvm, unsigned long i,
802                               struct kvm_memory_slot *memslot,
803                               unsigned long *rmapp, unsigned long gfn)
804 {
805         __be64 *hptep = (__be64 *) (kvm->arch.hpt.virt + (i << 4));
806         struct revmap_entry *rev = kvm->arch.hpt.rev;
807         unsigned long j, h;
808         unsigned long ptel, psize, rcbits;
809 
810         j = rev[i].forw;
811         if (j == i) {
812                 /* chain is now empty */
813                 *rmapp &= ~(KVMPPC_RMAP_PRESENT | KVMPPC_RMAP_INDEX);
814         } else {
815                 /* remove i from chain */
816                 h = rev[i].back;
817                 rev[h].forw = j;
818                 rev[j].back = h;
819                 rev[i].forw = rev[i].back = i;
820                 *rmapp = (*rmapp & ~KVMPPC_RMAP_INDEX) | j;
821         }
822 
823         /* Now check and modify the HPTE */
824         ptel = rev[i].guest_rpte;
825         psize = kvmppc_actual_pgsz(be64_to_cpu(hptep[0]), ptel);
826         if ((be64_to_cpu(hptep[0]) & HPTE_V_VALID) &&
827             hpte_rpn(ptel, psize) == gfn) {
828                 hptep[0] |= cpu_to_be64(HPTE_V_ABSENT);
829                 kvmppc_invalidate_hpte(kvm, hptep, i);
830                 hptep[1] &= ~cpu_to_be64(HPTE_R_KEY_HI | HPTE_R_KEY_LO);
831                 /* Harvest R and C */
832                 rcbits = be64_to_cpu(hptep[1]) & (HPTE_R_R | HPTE_R_C);
833                 *rmapp |= rcbits << KVMPPC_RMAP_RC_SHIFT;
834                 if ((rcbits & HPTE_R_C) && memslot->dirty_bitmap)
835                         kvmppc_update_dirty_map(memslot, gfn, psize);
836                 if (rcbits & ~rev[i].guest_rpte) {
837                         rev[i].guest_rpte = ptel | rcbits;
838                         note_hpte_modification(kvm, &rev[i]);
839                 }
840         }
841 }
842 
843 static int kvm_unmap_rmapp(struct kvm *kvm, struct kvm_memory_slot *memslot,
844                            unsigned long gfn)
845 {
846         unsigned long i;
847         __be64 *hptep;
848         unsigned long *rmapp;
849 
850         rmapp = &memslot->arch.rmap[gfn - memslot->base_gfn];
851         for (;;) {
852                 lock_rmap(rmapp);
853                 if (!(*rmapp & KVMPPC_RMAP_PRESENT)) {
854                         unlock_rmap(rmapp);
855                         break;
856                 }
857 
858                 /*
859                  * To avoid an ABBA deadlock with the HPTE lock bit,
860                  * we can't spin on the HPTE lock while holding the
861                  * rmap chain lock.
862                  */
863                 i = *rmapp & KVMPPC_RMAP_INDEX;
864                 hptep = (__be64 *) (kvm->arch.hpt.virt + (i << 4));
865                 if (!try_lock_hpte(hptep, HPTE_V_HVLOCK)) {
866                         /* unlock rmap before spinning on the HPTE lock */
867                         unlock_rmap(rmapp);
868                         while (be64_to_cpu(hptep[0]) & HPTE_V_HVLOCK)
869                                 cpu_relax();
870                         continue;
871                 }
872 
873                 kvmppc_unmap_hpte(kvm, i, memslot, rmapp, gfn);
874                 unlock_rmap(rmapp);
875                 __unlock_hpte(hptep, be64_to_cpu(hptep[0]));
876         }
877         return 0;
878 }
879 
880 int kvm_unmap_hva_range_hv(struct kvm *kvm, unsigned long start, unsigned long end)
881 {
882         hva_handler_fn handler;
883 
884         handler = kvm_is_radix(kvm) ? kvm_unmap_radix : kvm_unmap_rmapp;
885         kvm_handle_hva_range(kvm, start, end, handler);
886         return 0;
887 }
888 
889 void kvmppc_core_flush_memslot_hv(struct kvm *kvm,
890                                   struct kvm_memory_slot *memslot)
891 {
892         unsigned long gfn;
893         unsigned long n;
894         unsigned long *rmapp;
895 
896         gfn = memslot->base_gfn;
897         rmapp = memslot->arch.rmap;
898         if (kvm_is_radix(kvm)) {
899                 kvmppc_radix_flush_memslot(kvm, memslot);
900                 return;
901         }
902 
903         for (n = memslot->npages; n; --n, ++gfn) {
904                 /*
905                  * Testing the present bit without locking is OK because
906                  * the memslot has been marked invalid already, and hence
907                  * no new HPTEs referencing this page can be created,
908                  * thus the present bit can't go from 0 to 1.
909                  */
910                 if (*rmapp & KVMPPC_RMAP_PRESENT)
911                         kvm_unmap_rmapp(kvm, memslot, gfn);
912                 ++rmapp;
913         }
914 }
915 
916 static int kvm_age_rmapp(struct kvm *kvm, struct kvm_memory_slot *memslot,
917                          unsigned long gfn)
918 {
919         struct revmap_entry *rev = kvm->arch.hpt.rev;
920         unsigned long head, i, j;
921         __be64 *hptep;
922         int ret = 0;
923         unsigned long *rmapp;
924 
925         rmapp = &memslot->arch.rmap[gfn - memslot->base_gfn];
926  retry:
927         lock_rmap(rmapp);
928         if (*rmapp & KVMPPC_RMAP_REFERENCED) {
929                 *rmapp &= ~KVMPPC_RMAP_REFERENCED;
930                 ret = 1;
931         }
932         if (!(*rmapp & KVMPPC_RMAP_PRESENT)) {
933                 unlock_rmap(rmapp);
934                 return ret;
935         }
936 
937         i = head = *rmapp & KVMPPC_RMAP_INDEX;
938         do {
939                 hptep = (__be64 *) (kvm->arch.hpt.virt + (i << 4));
940                 j = rev[i].forw;
941 
942                 /* If this HPTE isn't referenced, ignore it */
943                 if (!(be64_to_cpu(hptep[1]) & HPTE_R_R))
944                         continue;
945 
946                 if (!try_lock_hpte(hptep, HPTE_V_HVLOCK)) {
947                         /* unlock rmap before spinning on the HPTE lock */
948                         unlock_rmap(rmapp);
949                         while (be64_to_cpu(hptep[0]) & HPTE_V_HVLOCK)
950                                 cpu_relax();
951                         goto retry;
952                 }
953 
954                 /* Now check and modify the HPTE */
955                 if ((be64_to_cpu(hptep[0]) & HPTE_V_VALID) &&
956                     (be64_to_cpu(hptep[1]) & HPTE_R_R)) {
957                         kvmppc_clear_ref_hpte(kvm, hptep, i);
958                         if (!(rev[i].guest_rpte & HPTE_R_R)) {
959                                 rev[i].guest_rpte |= HPTE_R_R;
960                                 note_hpte_modification(kvm, &rev[i]);
961                         }
962                         ret = 1;
963                 }
964                 __unlock_hpte(hptep, be64_to_cpu(hptep[0]));
965         } while ((i = j) != head);
966 
967         unlock_rmap(rmapp);
968         return ret;
969 }
970 
971 int kvm_age_hva_hv(struct kvm *kvm, unsigned long start, unsigned long end)
972 {
973         hva_handler_fn handler;
974 
975         handler = kvm_is_radix(kvm) ? kvm_age_radix : kvm_age_rmapp;
976         return kvm_handle_hva_range(kvm, start, end, handler);
977 }
978 
979 static int kvm_test_age_rmapp(struct kvm *kvm, struct kvm_memory_slot *memslot,
980                               unsigned long gfn)
981 {
982         struct revmap_entry *rev = kvm->arch.hpt.rev;
983         unsigned long head, i, j;
984         unsigned long *hp;
985         int ret = 1;
986         unsigned long *rmapp;
987 
988         rmapp = &memslot->arch.rmap[gfn - memslot->base_gfn];
989         if (*rmapp & KVMPPC_RMAP_REFERENCED)
990                 return 1;
991 
992         lock_rmap(rmapp);
993         if (*rmapp & KVMPPC_RMAP_REFERENCED)
994                 goto out;
995 
996         if (*rmapp & KVMPPC_RMAP_PRESENT) {
997                 i = head = *rmapp & KVMPPC_RMAP_INDEX;
998                 do {
999                         hp = (unsigned long *)(kvm->arch.hpt.virt + (i << 4));
1000                         j = rev[i].forw;
1001                         if (be64_to_cpu(hp[1]) & HPTE_R_R)
1002                                 goto out;
1003                 } while ((i = j) != head);
1004         }
1005         ret = 0;
1006 
1007  out:
1008         unlock_rmap(rmapp);
1009         return ret;
1010 }
1011 
1012 int kvm_test_age_hva_hv(struct kvm *kvm, unsigned long hva)
1013 {
1014         hva_handler_fn handler;
1015 
1016         handler = kvm_is_radix(kvm) ? kvm_test_age_radix : kvm_test_age_rmapp;
1017         return kvm_handle_hva(kvm, hva, handler);
1018 }
1019 
1020 void kvm_set_spte_hva_hv(struct kvm *kvm, unsigned long hva, pte_t pte)
1021 {
1022         hva_handler_fn handler;
1023 
1024         handler = kvm_is_radix(kvm) ? kvm_unmap_radix : kvm_unmap_rmapp;
1025         kvm_handle_hva(kvm, hva, handler);
1026 }
1027 
1028 static int vcpus_running(struct kvm *kvm)
1029 {
1030         return atomic_read(&kvm->arch.vcpus_running) != 0;
1031 }
1032 
1033 /*
1034  * Returns the number of system pages that are dirty.
1035  * This can be more than 1 if we find a huge-page HPTE.
1036  */
1037 static int kvm_test_clear_dirty_npages(struct kvm *kvm, unsigned long *rmapp)
1038 {
1039         struct revmap_entry *rev = kvm->arch.hpt.rev;
1040         unsigned long head, i, j;
1041         unsigned long n;
1042         unsigned long v, r;
1043         __be64 *hptep;
1044         int npages_dirty = 0;
1045 
1046  retry:
1047         lock_rmap(rmapp);
1048         if (!(*rmapp & KVMPPC_RMAP_PRESENT)) {
1049                 unlock_rmap(rmapp);
1050                 return npages_dirty;
1051         }
1052 
1053         i = head = *rmapp & KVMPPC_RMAP_INDEX;
1054         do {
1055                 unsigned long hptep1;
1056                 hptep = (__be64 *) (kvm->arch.hpt.virt + (i << 4));
1057                 j = rev[i].forw;
1058 
1059                 /*
1060                  * Checking the C (changed) bit here is racy since there
1061                  * is no guarantee about when the hardware writes it back.
1062                  * If the HPTE is not writable then it is stable since the
1063                  * page can't be written to, and we would have done a tlbie
1064                  * (which forces the hardware to complete any writeback)
1065                  * when making the HPTE read-only.
1066                  * If vcpus are running then this call is racy anyway
1067                  * since the page could get dirtied subsequently, so we
1068                  * expect there to be a further call which would pick up
1069                  * any delayed C bit writeback.
1070                  * Otherwise we need to do the tlbie even if C==0 in
1071                  * order to pick up any delayed writeback of C.
1072                  */
1073                 hptep1 = be64_to_cpu(hptep[1]);
1074                 if (!(hptep1 & HPTE_R_C) &&
1075                     (!hpte_is_writable(hptep1) || vcpus_running(kvm)))
1076                         continue;
1077 
1078                 if (!try_lock_hpte(hptep, HPTE_V_HVLOCK)) {
1079                         /* unlock rmap before spinning on the HPTE lock */
1080                         unlock_rmap(rmapp);
1081                         while (hptep[0] & cpu_to_be64(HPTE_V_HVLOCK))
1082                                 cpu_relax();
1083                         goto retry;
1084                 }
1085 
1086                 /* Now check and modify the HPTE */
1087                 if (!(hptep[0] & cpu_to_be64(HPTE_V_VALID))) {
1088                         __unlock_hpte(hptep, be64_to_cpu(hptep[0]));
1089                         continue;
1090                 }
1091 
1092                 /* need to make it temporarily absent so C is stable */
1093                 hptep[0] |= cpu_to_be64(HPTE_V_ABSENT);
1094                 kvmppc_invalidate_hpte(kvm, hptep, i);
1095                 v = be64_to_cpu(hptep[0]);
1096                 r = be64_to_cpu(hptep[1]);
1097                 if (r & HPTE_R_C) {
1098                         hptep[1] = cpu_to_be64(r & ~HPTE_R_C);
1099                         if (!(rev[i].guest_rpte & HPTE_R_C)) {
1100                                 rev[i].guest_rpte |= HPTE_R_C;
1101                                 note_hpte_modification(kvm, &rev[i]);
1102                         }
1103                         n = kvmppc_actual_pgsz(v, r);
1104                         n = (n + PAGE_SIZE - 1) >> PAGE_SHIFT;
1105                         if (n > npages_dirty)
1106                                 npages_dirty = n;
1107                         eieio();
1108                 }
1109                 v &= ~HPTE_V_ABSENT;
1110                 v |= HPTE_V_VALID;
1111                 __unlock_hpte(hptep, v);
1112         } while ((i = j) != head);
1113 
1114         unlock_rmap(rmapp);
1115         return npages_dirty;
1116 }
1117 
1118 void kvmppc_harvest_vpa_dirty(struct kvmppc_vpa *vpa,
1119                               struct kvm_memory_slot *memslot,
1120                               unsigned long *map)
1121 {
1122         unsigned long gfn;
1123 
1124         if (!vpa->dirty || !vpa->pinned_addr)
1125                 return;
1126         gfn = vpa->gpa >> PAGE_SHIFT;
1127         if (gfn < memslot->base_gfn ||
1128             gfn >= memslot->base_gfn + memslot->npages)
1129                 return;
1130 
1131         vpa->dirty = false;
1132         if (map)
1133                 __set_bit_le(gfn - memslot->base_gfn, map);
1134 }
1135 
1136 long kvmppc_hv_get_dirty_log_hpt(struct kvm *kvm,
1137                         struct kvm_memory_slot *memslot, unsigned long *map)
1138 {
1139         unsigned long i;
1140         unsigned long *rmapp;
1141 
1142         preempt_disable();
1143         rmapp = memslot->arch.rmap;
1144         for (i = 0; i < memslot->npages; ++i) {
1145                 int npages = kvm_test_clear_dirty_npages(kvm, rmapp);
1146                 /*
1147                  * Note that if npages > 0 then i must be a multiple of npages,
1148                  * since we always put huge-page HPTEs in the rmap chain
1149                  * corresponding to their page base address.
1150                  */
1151                 if (npages)
1152                         set_dirty_bits(map, i, npages);
1153                 ++rmapp;
1154         }
1155         preempt_enable();
1156         return 0;
1157 }
1158 
1159 void *kvmppc_pin_guest_page(struct kvm *kvm, unsigned long gpa,
1160                             unsigned long *nb_ret)
1161 {
1162         struct kvm_memory_slot *memslot;
1163         unsigned long gfn = gpa >> PAGE_SHIFT;
1164         struct page *page, *pages[1];
1165         int npages;
1166         unsigned long hva, offset;
1167         int srcu_idx;
1168 
1169         srcu_idx = srcu_read_lock(&kvm->srcu);
1170         memslot = gfn_to_memslot(kvm, gfn);
1171         if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID))
1172                 goto err;
1173         hva = gfn_to_hva_memslot(memslot, gfn);
1174         npages = get_user_pages_fast(hva, 1, FOLL_WRITE, pages);
1175         if (npages < 1)
1176                 goto err;
1177         page = pages[0];
1178         srcu_read_unlock(&kvm->srcu, srcu_idx);
1179 
1180         offset = gpa & (PAGE_SIZE - 1);
1181         if (nb_ret)
1182                 *nb_ret = PAGE_SIZE - offset;
1183         return page_address(page) + offset;
1184 
1185  err:
1186         srcu_read_unlock(&kvm->srcu, srcu_idx);
1187         return NULL;
1188 }
1189 
1190 void kvmppc_unpin_guest_page(struct kvm *kvm, void *va, unsigned long gpa,
1191                              bool dirty)
1192 {
1193         struct page *page = virt_to_page(va);
1194         struct kvm_memory_slot *memslot;
1195         unsigned long gfn;
1196         int srcu_idx;
1197 
1198         put_page(page);
1199 
1200         if (!dirty)
1201                 return;
1202 
1203         /* We need to mark this page dirty in the memslot dirty_bitmap, if any */
1204         gfn = gpa >> PAGE_SHIFT;
1205         srcu_idx = srcu_read_lock(&kvm->srcu);
1206         memslot = gfn_to_memslot(kvm, gfn);
1207         if (memslot && memslot->dirty_bitmap)
1208                 set_bit_le(gfn - memslot->base_gfn, memslot->dirty_bitmap);
1209         srcu_read_unlock(&kvm->srcu, srcu_idx);
1210 }
1211 
1212 /*
1213  * HPT resizing
1214  */
1215 static int resize_hpt_allocate(struct kvm_resize_hpt *resize)
1216 {
1217         int rc;
1218 
1219         rc = kvmppc_allocate_hpt(&resize->hpt, resize->order);
1220         if (rc < 0)
1221                 return rc;
1222 
1223         resize_hpt_debug(resize, "resize_hpt_allocate(): HPT @ 0x%lx\n",
1224                          resize->hpt.virt);
1225 
1226         return 0;
1227 }
1228 
1229 static unsigned long resize_hpt_rehash_hpte(struct kvm_resize_hpt *resize,
1230                                             unsigned long idx)
1231 {
1232         struct kvm *kvm = resize->kvm;
1233         struct kvm_hpt_info *old = &kvm->arch.hpt;
1234         struct kvm_hpt_info *new = &resize->hpt;
1235         unsigned long old_hash_mask = (1ULL << (old->order - 7)) - 1;
1236         unsigned long new_hash_mask = (1ULL << (new->order - 7)) - 1;
1237         __be64 *hptep, *new_hptep;
1238         unsigned long vpte, rpte, guest_rpte;
1239         int ret;
1240         struct revmap_entry *rev;
1241         unsigned long apsize, avpn, pteg, hash;
1242         unsigned long new_idx, new_pteg, replace_vpte;
1243         int pshift;
1244 
1245         hptep = (__be64 *)(old->virt + (idx << 4));
1246 
1247         /* Guest is stopped, so new HPTEs can't be added or faulted
1248          * in, only unmapped or altered by host actions.  So, it's
1249          * safe to check this before we take the HPTE lock */
1250         vpte = be64_to_cpu(hptep[0]);
1251         if (!(vpte & HPTE_V_VALID) && !(vpte & HPTE_V_ABSENT))
1252                 return 0; /* nothing to do */
1253 
1254         while (!try_lock_hpte(hptep, HPTE_V_HVLOCK))
1255                 cpu_relax();
1256 
1257         vpte = be64_to_cpu(hptep[0]);
1258 
1259         ret = 0;
1260         if (!(vpte & HPTE_V_VALID) && !(vpte & HPTE_V_ABSENT))
1261                 /* Nothing to do */
1262                 goto out;
1263 
1264         if (cpu_has_feature(CPU_FTR_ARCH_300)) {
1265                 rpte = be64_to_cpu(hptep[1]);
1266                 vpte = hpte_new_to_old_v(vpte, rpte);
1267         }
1268 
1269         /* Unmap */
1270         rev = &old->rev[idx];
1271         guest_rpte = rev->guest_rpte;
1272 
1273         ret = -EIO;
1274         apsize = kvmppc_actual_pgsz(vpte, guest_rpte);
1275         if (!apsize)
1276                 goto out;
1277 
1278         if (vpte & HPTE_V_VALID) {
1279                 unsigned long gfn = hpte_rpn(guest_rpte, apsize);
1280                 int srcu_idx = srcu_read_lock(&kvm->srcu);
1281                 struct kvm_memory_slot *memslot =
1282                         __gfn_to_memslot(kvm_memslots(kvm), gfn);
1283 
1284                 if (memslot) {
1285                         unsigned long *rmapp;
1286                         rmapp = &memslot->arch.rmap[gfn - memslot->base_gfn];
1287 
1288                         lock_rmap(rmapp);
1289                         kvmppc_unmap_hpte(kvm, idx, memslot, rmapp, gfn);
1290                         unlock_rmap(rmapp);
1291                 }
1292 
1293                 srcu_read_unlock(&kvm->srcu, srcu_idx);
1294         }
1295 
1296         /* Reload PTE after unmap */
1297         vpte = be64_to_cpu(hptep[0]);
1298         BUG_ON(vpte & HPTE_V_VALID);
1299         BUG_ON(!(vpte & HPTE_V_ABSENT));
1300 
1301         ret = 0;
1302         if (!(vpte & HPTE_V_BOLTED))
1303                 goto out;
1304 
1305         rpte = be64_to_cpu(hptep[1]);
1306 
1307         if (cpu_has_feature(CPU_FTR_ARCH_300)) {
1308                 vpte = hpte_new_to_old_v(vpte, rpte);
1309                 rpte = hpte_new_to_old_r(rpte);
1310         }
1311 
1312         pshift = kvmppc_hpte_base_page_shift(vpte, rpte);
1313         avpn = HPTE_V_AVPN_VAL(vpte) & ~(((1ul << pshift) - 1) >> 23);
1314         pteg = idx / HPTES_PER_GROUP;
1315         if (vpte & HPTE_V_SECONDARY)
1316                 pteg = ~pteg;
1317 
1318         if (!(vpte & HPTE_V_1TB_SEG)) {
1319                 unsigned long offset, vsid;
1320 
1321                 /* We only have 28 - 23 bits of offset in avpn */
1322                 offset = (avpn & 0x1f) << 23;
1323                 vsid = avpn >> 5;
1324                 /* We can find more bits from the pteg value */
1325                 if (pshift < 23)
1326                         offset |= ((vsid ^ pteg) & old_hash_mask) << pshift;
1327 
1328                 hash = vsid ^ (offset >> pshift);
1329         } else {
1330                 unsigned long offset, vsid;
1331 
1332                 /* We only have 40 - 23 bits of seg_off in avpn */
1333                 offset = (avpn & 0x1ffff) << 23;
1334                 vsid = avpn >> 17;
1335                 if (pshift < 23)
1336                         offset |= ((vsid ^ (vsid << 25) ^ pteg) & old_hash_mask) << pshift;
1337 
1338                 hash = vsid ^ (vsid << 25) ^ (offset >> pshift);
1339         }
1340 
1341         new_pteg = hash & new_hash_mask;
1342         if (vpte & HPTE_V_SECONDARY)
1343                 new_pteg = ~hash & new_hash_mask;
1344 
1345         new_idx = new_pteg * HPTES_PER_GROUP + (idx % HPTES_PER_GROUP);
1346         new_hptep = (__be64 *)(new->virt + (new_idx << 4));
1347 
1348         replace_vpte = be64_to_cpu(new_hptep[0]);
1349         if (cpu_has_feature(CPU_FTR_ARCH_300)) {
1350                 unsigned long replace_rpte = be64_to_cpu(new_hptep[1]);
1351                 replace_vpte = hpte_new_to_old_v(replace_vpte, replace_rpte);
1352         }
1353 
1354         if (replace_vpte & (HPTE_V_VALID | HPTE_V_ABSENT)) {
1355                 BUG_ON(new->order >= old->order);
1356 
1357                 if (replace_vpte & HPTE_V_BOLTED) {
1358                         if (vpte & HPTE_V_BOLTED)
1359                                 /* Bolted collision, nothing we can do */
1360                                 ret = -ENOSPC;
1361                         /* Discard the new HPTE */
1362                         goto out;
1363                 }
1364 
1365                 /* Discard the previous HPTE */
1366         }
1367 
1368         if (cpu_has_feature(CPU_FTR_ARCH_300)) {
1369                 rpte = hpte_old_to_new_r(vpte, rpte);
1370                 vpte = hpte_old_to_new_v(vpte);
1371         }
1372 
1373         new_hptep[1] = cpu_to_be64(rpte);
1374         new->rev[new_idx].guest_rpte = guest_rpte;
1375         /* No need for a barrier, since new HPT isn't active */
1376         new_hptep[0] = cpu_to_be64(vpte);
1377         unlock_hpte(new_hptep, vpte);
1378 
1379 out:
1380         unlock_hpte(hptep, vpte);
1381         return ret;
1382 }
1383 
1384 static int resize_hpt_rehash(struct kvm_resize_hpt *resize)
1385 {
1386         struct kvm *kvm = resize->kvm;
1387         unsigned  long i;
1388         int rc;
1389 
1390         for (i = 0; i < kvmppc_hpt_npte(&kvm->arch.hpt); i++) {
1391                 rc = resize_hpt_rehash_hpte(resize, i);
1392                 if (rc != 0)
1393                         return rc;
1394         }
1395 
1396         return 0;
1397 }
1398 
1399 static void resize_hpt_pivot(struct kvm_resize_hpt *resize)
1400 {
1401         struct kvm *kvm = resize->kvm;
1402         struct kvm_hpt_info hpt_tmp;
1403 
1404         /* Exchange the pending tables in the resize structure with
1405          * the active tables */
1406 
1407         resize_hpt_debug(resize, "resize_hpt_pivot()\n");
1408 
1409         spin_lock(&kvm->mmu_lock);
1410         asm volatile("ptesync" : : : "memory");
1411 
1412         hpt_tmp = kvm->arch.hpt;
1413         kvmppc_set_hpt(kvm, &resize->hpt);
1414         resize->hpt = hpt_tmp;
1415 
1416         spin_unlock(&kvm->mmu_lock);
1417 
1418         synchronize_srcu_expedited(&kvm->srcu);
1419 
1420         if (cpu_has_feature(CPU_FTR_ARCH_300))
1421                 kvmppc_setup_partition_table(kvm);
1422 
1423         resize_hpt_debug(resize, "resize_hpt_pivot() done\n");
1424 }
1425 
1426 static void resize_hpt_release(struct kvm *kvm, struct kvm_resize_hpt *resize)
1427 {
1428         if (WARN_ON(!mutex_is_locked(&kvm->arch.mmu_setup_lock)))
1429                 return;
1430 
1431         if (!resize)
1432                 return;
1433 
1434         if (resize->error != -EBUSY) {
1435                 if (resize->hpt.virt)
1436                         kvmppc_free_hpt(&resize->hpt);
1437                 kfree(resize);
1438         }
1439 
1440         if (kvm->arch.resize_hpt == resize)
1441                 kvm->arch.resize_hpt = NULL;
1442 }
1443 
1444 static void resize_hpt_prepare_work(struct work_struct *work)
1445 {
1446         struct kvm_resize_hpt *resize = container_of(work,
1447                                                      struct kvm_resize_hpt,
1448                                                      work);
1449         struct kvm *kvm = resize->kvm;
1450         int err = 0;
1451 
1452         if (WARN_ON(resize->error != -EBUSY))
1453                 return;
1454 
1455         mutex_lock(&kvm->arch.mmu_setup_lock);
1456 
1457         /* Request is still current? */
1458         if (kvm->arch.resize_hpt == resize) {
1459                 /* We may request large allocations here:
1460                  * do not sleep with kvm->arch.mmu_setup_lock held for a while.
1461                  */
1462                 mutex_unlock(&kvm->arch.mmu_setup_lock);
1463 
1464                 resize_hpt_debug(resize, "resize_hpt_prepare_work(): order = %d\n",
1465                                  resize->order);
1466 
1467                 err = resize_hpt_allocate(resize);
1468 
1469                 /* We have strict assumption about -EBUSY
1470                  * when preparing for HPT resize.
1471                  */
1472                 if (WARN_ON(err == -EBUSY))
1473                         err = -EINPROGRESS;
1474 
1475                 mutex_lock(&kvm->arch.mmu_setup_lock);
1476                 /* It is possible that kvm->arch.resize_hpt != resize
1477                  * after we grab kvm->arch.mmu_setup_lock again.
1478                  */
1479         }
1480 
1481         resize->error = err;
1482 
1483         if (kvm->arch.resize_hpt != resize)
1484                 resize_hpt_release(kvm, resize);
1485 
1486         mutex_unlock(&kvm->arch.mmu_setup_lock);
1487 }
1488 
1489 long kvm_vm_ioctl_resize_hpt_prepare(struct kvm *kvm,
1490                                      struct kvm_ppc_resize_hpt *rhpt)
1491 {
1492         unsigned long flags = rhpt->flags;
1493         unsigned long shift = rhpt->shift;
1494         struct kvm_resize_hpt *resize;
1495         int ret;
1496 
1497         if (flags != 0 || kvm_is_radix(kvm))
1498                 return -EINVAL;
1499 
1500         if (shift && ((shift < 18) || (shift > 46)))
1501                 return -EINVAL;
1502 
1503         mutex_lock(&kvm->arch.mmu_setup_lock);
1504 
1505         resize = kvm->arch.resize_hpt;
1506 
1507         if (resize) {
1508                 if (resize->order == shift) {
1509                         /* Suitable resize in progress? */
1510                         ret = resize->error;
1511                         if (ret == -EBUSY)
1512                                 ret = 100; /* estimated time in ms */
1513                         else if (ret)
1514                                 resize_hpt_release(kvm, resize);
1515 
1516                         goto out;
1517                 }
1518 
1519                 /* not suitable, cancel it */
1520                 resize_hpt_release(kvm, resize);
1521         }
1522 
1523         ret = 0;
1524         if (!shift)
1525                 goto out; /* nothing to do */
1526 
1527         /* start new resize */
1528 
1529         resize = kzalloc(sizeof(*resize), GFP_KERNEL);
1530         if (!resize) {
1531                 ret = -ENOMEM;
1532                 goto out;
1533         }
1534 
1535         resize->error = -EBUSY;
1536         resize->order = shift;
1537         resize->kvm = kvm;
1538         INIT_WORK(&resize->work, resize_hpt_prepare_work);
1539         kvm->arch.resize_hpt = resize;
1540 
1541         schedule_work(&resize->work);
1542 
1543         ret = 100; /* estimated time in ms */
1544 
1545 out:
1546         mutex_unlock(&kvm->arch.mmu_setup_lock);
1547         return ret;
1548 }
1549 
1550 static void resize_hpt_boot_vcpu(void *opaque)
1551 {
1552         /* Nothing to do, just force a KVM exit */
1553 }
1554 
1555 long kvm_vm_ioctl_resize_hpt_commit(struct kvm *kvm,
1556                                     struct kvm_ppc_resize_hpt *rhpt)
1557 {
1558         unsigned long flags = rhpt->flags;
1559         unsigned long shift = rhpt->shift;
1560         struct kvm_resize_hpt *resize;
1561         long ret;
1562 
1563         if (flags != 0 || kvm_is_radix(kvm))
1564                 return -EINVAL;
1565 
1566         if (shift && ((shift < 18) || (shift > 46)))
1567                 return -EINVAL;
1568 
1569         mutex_lock(&kvm->arch.mmu_setup_lock);
1570 
1571         resize = kvm->arch.resize_hpt;
1572 
1573         /* This shouldn't be possible */
1574         ret = -EIO;
1575         if (WARN_ON(!kvm->arch.mmu_ready))
1576                 goto out_no_hpt;
1577 
1578         /* Stop VCPUs from running while we mess with the HPT */
1579         kvm->arch.mmu_ready = 0;
1580         smp_mb();
1581 
1582         /* Boot all CPUs out of the guest so they re-read
1583          * mmu_ready */
1584         on_each_cpu(resize_hpt_boot_vcpu, NULL, 1);
1585 
1586         ret = -ENXIO;
1587         if (!resize || (resize->order != shift))
1588                 goto out;
1589 
1590         ret = resize->error;
1591         if (ret)
1592                 goto out;
1593 
1594         ret = resize_hpt_rehash(resize);
1595         if (ret)
1596                 goto out;
1597 
1598         resize_hpt_pivot(resize);
1599 
1600 out:
1601         /* Let VCPUs run again */
1602         kvm->arch.mmu_ready = 1;
1603         smp_mb();
1604 out_no_hpt:
1605         resize_hpt_release(kvm, resize);
1606         mutex_unlock(&kvm->arch.mmu_setup_lock);
1607         return ret;
1608 }
1609 
1610 /*
1611  * Functions for reading and writing the hash table via reads and
1612  * writes on a file descriptor.
1613  *
1614  * Reads return the guest view of the hash table, which has to be
1615  * pieced together from the real hash table and the guest_rpte
1616  * values in the revmap array.
1617  *
1618  * On writes, each HPTE written is considered in turn, and if it
1619  * is valid, it is written to the HPT as if an H_ENTER with the
1620  * exact flag set was done.  When the invalid count is non-zero
1621  * in the header written to the stream, the kernel will make
1622  * sure that that many HPTEs are invalid, and invalidate them
1623  * if not.
1624  */
1625 
1626 struct kvm_htab_ctx {
1627         unsigned long   index;
1628         unsigned long   flags;
1629         struct kvm      *kvm;
1630         int             first_pass;
1631 };
1632 
1633 #define HPTE_SIZE       (2 * sizeof(unsigned long))
1634 
1635 /*
1636  * Returns 1 if this HPT entry has been modified or has pending
1637  * R/C bit changes.
1638  */
1639 static int hpte_dirty(struct revmap_entry *revp, __be64 *hptp)
1640 {
1641         unsigned long rcbits_unset;
1642 
1643         if (revp->guest_rpte & HPTE_GR_MODIFIED)
1644                 return 1;
1645 
1646         /* Also need to consider changes in reference and changed bits */
1647         rcbits_unset = ~revp->guest_rpte & (HPTE_R_R | HPTE_R_C);
1648         if ((be64_to_cpu(hptp[0]) & HPTE_V_VALID) &&
1649             (be64_to_cpu(hptp[1]) & rcbits_unset))
1650                 return 1;
1651 
1652         return 0;
1653 }
1654 
1655 static long record_hpte(unsigned long flags, __be64 *hptp,
1656                         unsigned long *hpte, struct revmap_entry *revp,
1657                         int want_valid, int first_pass)
1658 {
1659         unsigned long v, r, hr;
1660         unsigned long rcbits_unset;
1661         int ok = 1;
1662         int valid, dirty;
1663 
1664         /* Unmodified entries are uninteresting except on the first pass */
1665         dirty = hpte_dirty(revp, hptp);
1666         if (!first_pass && !dirty)
1667                 return 0;
1668 
1669         valid = 0;
1670         if (be64_to_cpu(hptp[0]) & (HPTE_V_VALID | HPTE_V_ABSENT)) {
1671                 valid = 1;
1672                 if ((flags & KVM_GET_HTAB_BOLTED_ONLY) &&
1673                     !(be64_to_cpu(hptp[0]) & HPTE_V_BOLTED))
1674                         valid = 0;
1675         }
1676         if (valid != want_valid)
1677                 return 0;
1678 
1679         v = r = 0;
1680         if (valid || dirty) {
1681                 /* lock the HPTE so it's stable and read it */
1682                 preempt_disable();
1683                 while (!try_lock_hpte(hptp, HPTE_V_HVLOCK))
1684                         cpu_relax();
1685                 v = be64_to_cpu(hptp[0]);
1686                 hr = be64_to_cpu(hptp[1]);
1687                 if (cpu_has_feature(CPU_FTR_ARCH_300)) {
1688                         v = hpte_new_to_old_v(v, hr);
1689                         hr = hpte_new_to_old_r(hr);
1690                 }
1691 
1692                 /* re-evaluate valid and dirty from synchronized HPTE value */
1693                 valid = !!(v & HPTE_V_VALID);
1694                 dirty = !!(revp->guest_rpte & HPTE_GR_MODIFIED);
1695 
1696                 /* Harvest R and C into guest view if necessary */
1697                 rcbits_unset = ~revp->guest_rpte & (HPTE_R_R | HPTE_R_C);
1698                 if (valid && (rcbits_unset & hr)) {
1699                         revp->guest_rpte |= (hr &
1700                                 (HPTE_R_R | HPTE_R_C)) | HPTE_GR_MODIFIED;
1701                         dirty = 1;
1702                 }
1703 
1704                 if (v & HPTE_V_ABSENT) {
1705                         v &= ~HPTE_V_ABSENT;
1706                         v |= HPTE_V_VALID;
1707                         valid = 1;
1708                 }
1709                 if ((flags & KVM_GET_HTAB_BOLTED_ONLY) && !(v & HPTE_V_BOLTED))
1710                         valid = 0;
1711 
1712                 r = revp->guest_rpte;
1713                 /* only clear modified if this is the right sort of entry */
1714                 if (valid == want_valid && dirty) {
1715                         r &= ~HPTE_GR_MODIFIED;
1716                         revp->guest_rpte = r;
1717                 }
1718                 unlock_hpte(hptp, be64_to_cpu(hptp[0]));
1719                 preempt_enable();
1720                 if (!(valid == want_valid && (first_pass || dirty)))
1721                         ok = 0;
1722         }
1723         hpte[0] = cpu_to_be64(v);
1724         hpte[1] = cpu_to_be64(r);
1725         return ok;
1726 }
1727 
1728 static ssize_t kvm_htab_read(struct file *file, char __user *buf,
1729                              size_t count, loff_t *ppos)
1730 {
1731         struct kvm_htab_ctx *ctx = file->private_data;
1732         struct kvm *kvm = ctx->kvm;
1733         struct kvm_get_htab_header hdr;
1734         __be64 *hptp;
1735         struct revmap_entry *revp;
1736         unsigned long i, nb, nw;
1737         unsigned long __user *lbuf;
1738         struct kvm_get_htab_header __user *hptr;
1739         unsigned long flags;
1740         int first_pass;
1741         unsigned long hpte[2];
1742 
1743         if (!access_ok(buf, count))
1744                 return -EFAULT;
1745         if (kvm_is_radix(kvm))
1746                 return 0;
1747 
1748         first_pass = ctx->first_pass;
1749         flags = ctx->flags;
1750 
1751         i = ctx->index;
1752         hptp = (__be64 *)(kvm->arch.hpt.virt + (i * HPTE_SIZE));
1753         revp = kvm->arch.hpt.rev + i;
1754         lbuf = (unsigned long __user *)buf;
1755 
1756         nb = 0;
1757         while (nb + sizeof(hdr) + HPTE_SIZE < count) {
1758                 /* Initialize header */
1759                 hptr = (struct kvm_get_htab_header __user *)buf;
1760                 hdr.n_valid = 0;
1761                 hdr.n_invalid = 0;
1762                 nw = nb;
1763                 nb += sizeof(hdr);
1764                 lbuf = (unsigned long __user *)(buf + sizeof(hdr));
1765 
1766                 /* Skip uninteresting entries, i.e. clean on not-first pass */
1767                 if (!first_pass) {
1768                         while (i < kvmppc_hpt_npte(&kvm->arch.hpt) &&
1769                                !hpte_dirty(revp, hptp)) {
1770                                 ++i;
1771                                 hptp += 2;
1772                                 ++revp;
1773                         }
1774                 }
1775                 hdr.index = i;
1776 
1777                 /* Grab a series of valid entries */
1778                 while (i < kvmppc_hpt_npte(&kvm->arch.hpt) &&
1779                        hdr.n_valid < 0xffff &&
1780                        nb + HPTE_SIZE < count &&
1781                        record_hpte(flags, hptp, hpte, revp, 1, first_pass)) {
1782                         /* valid entry, write it out */
1783                         ++hdr.n_valid;
1784                         if (__put_user(hpte[0], lbuf) ||
1785                             __put_user(hpte[1], lbuf + 1))
1786                                 return -EFAULT;
1787                         nb += HPTE_SIZE;
1788                         lbuf += 2;
1789                         ++i;
1790                         hptp += 2;
1791                         ++revp;
1792                 }
1793                 /* Now skip invalid entries while we can */
1794                 while (i < kvmppc_hpt_npte(&kvm->arch.hpt) &&
1795                        hdr.n_invalid < 0xffff &&
1796                        record_hpte(flags, hptp, hpte, revp, 0, first_pass)) {
1797                         /* found an invalid entry */
1798                         ++hdr.n_invalid;
1799                         ++i;
1800                         hptp += 2;
1801                         ++revp;
1802                 }
1803 
1804                 if (hdr.n_valid || hdr.n_invalid) {
1805                         /* write back the header */
1806                         if (__copy_to_user(hptr, &hdr, sizeof(hdr)))
1807                                 return -EFAULT;
1808                         nw = nb;
1809                         buf = (char __user *)lbuf;
1810                 } else {
1811                         nb = nw;
1812                 }
1813 
1814                 /* Check if we've wrapped around the hash table */
1815                 if (i >= kvmppc_hpt_npte(&kvm->arch.hpt)) {
1816                         i = 0;
1817                         ctx->first_pass = 0;
1818                         break;
1819                 }
1820         }
1821 
1822         ctx->index = i;
1823 
1824         return nb;
1825 }
1826 
1827 static ssize_t kvm_htab_write(struct file *file, const char __user *buf,
1828                               size_t count, loff_t *ppos)
1829 {
1830         struct kvm_htab_ctx *ctx = file->private_data;
1831         struct kvm *kvm = ctx->kvm;
1832         struct kvm_get_htab_header hdr;
1833         unsigned long i, j;
1834         unsigned long v, r;
1835         unsigned long __user *lbuf;
1836         __be64 *hptp;
1837         unsigned long tmp[2];
1838         ssize_t nb;
1839         long int err, ret;
1840         int mmu_ready;
1841         int pshift;
1842 
1843         if (!access_ok(buf, count))
1844                 return -EFAULT;
1845         if (kvm_is_radix(kvm))
1846                 return -EINVAL;
1847 
1848         /* lock out vcpus from running while we're doing this */
1849         mutex_lock(&kvm->arch.mmu_setup_lock);
1850         mmu_ready = kvm->arch.mmu_ready;
1851         if (mmu_ready) {
1852                 kvm->arch.mmu_ready = 0;        /* temporarily */
1853                 /* order mmu_ready vs. vcpus_running */
1854                 smp_mb();
1855                 if (atomic_read(&kvm->arch.vcpus_running)) {
1856                         kvm->arch.mmu_ready = 1;
1857                         mutex_unlock(&kvm->arch.mmu_setup_lock);
1858                         return -EBUSY;
1859                 }
1860         }
1861 
1862         err = 0;
1863         for (nb = 0; nb + sizeof(hdr) <= count; ) {
1864                 err = -EFAULT;
1865                 if (__copy_from_user(&hdr, buf, sizeof(hdr)))
1866                         break;
1867 
1868                 err = 0;
1869                 if (nb + hdr.n_valid * HPTE_SIZE > count)
1870                         break;
1871 
1872                 nb += sizeof(hdr);
1873                 buf += sizeof(hdr);
1874 
1875                 err = -EINVAL;
1876                 i = hdr.index;
1877                 if (i >= kvmppc_hpt_npte(&kvm->arch.hpt) ||
1878                     i + hdr.n_valid + hdr.n_invalid > kvmppc_hpt_npte(&kvm->arch.hpt))
1879                         break;
1880 
1881                 hptp = (__be64 *)(kvm->arch.hpt.virt + (i * HPTE_SIZE));
1882                 lbuf = (unsigned long __user *)buf;
1883                 for (j = 0; j < hdr.n_valid; ++j) {
1884                         __be64 hpte_v;
1885                         __be64 hpte_r;
1886 
1887                         err = -EFAULT;
1888                         if (__get_user(hpte_v, lbuf) ||
1889                             __get_user(hpte_r, lbuf + 1))
1890                                 goto out;
1891                         v = be64_to_cpu(hpte_v);
1892                         r = be64_to_cpu(hpte_r);
1893                         err = -EINVAL;
1894                         if (!(v & HPTE_V_VALID))
1895                                 goto out;
1896                         pshift = kvmppc_hpte_base_page_shift(v, r);
1897                         if (pshift <= 0)
1898                                 goto out;
1899                         lbuf += 2;
1900                         nb += HPTE_SIZE;
1901 
1902                         if (be64_to_cpu(hptp[0]) & (HPTE_V_VALID | HPTE_V_ABSENT))
1903                                 kvmppc_do_h_remove(kvm, 0, i, 0, tmp);
1904                         err = -EIO;
1905                         ret = kvmppc_virtmode_do_h_enter(kvm, H_EXACT, i, v, r,
1906                                                          tmp);
1907                         if (ret != H_SUCCESS) {
1908                                 pr_err("kvm_htab_write ret %ld i=%ld v=%lx "
1909                                        "r=%lx\n", ret, i, v, r);
1910                                 goto out;
1911                         }
1912                         if (!mmu_ready && is_vrma_hpte(v)) {
1913                                 unsigned long senc, lpcr;
1914 
1915                                 senc = slb_pgsize_encoding(1ul << pshift);
1916                                 kvm->arch.vrma_slb_v = senc | SLB_VSID_B_1T |
1917                                         (VRMA_VSID << SLB_VSID_SHIFT_1T);
1918                                 if (!cpu_has_feature(CPU_FTR_ARCH_300)) {
1919                                         lpcr = senc << (LPCR_VRMASD_SH - 4);
1920                                         kvmppc_update_lpcr(kvm, lpcr,
1921                                                            LPCR_VRMASD);
1922                                 } else {
1923                                         kvmppc_setup_partition_table(kvm);
1924                                 }
1925                                 mmu_ready = 1;
1926                         }
1927                         ++i;
1928                         hptp += 2;
1929                 }
1930 
1931                 for (j = 0; j < hdr.n_invalid; ++j) {
1932                         if (be64_to_cpu(hptp[0]) & (HPTE_V_VALID | HPTE_V_ABSENT))
1933                                 kvmppc_do_h_remove(kvm, 0, i, 0, tmp);
1934                         ++i;
1935                         hptp += 2;
1936                 }
1937                 err = 0;
1938         }
1939 
1940  out:
1941         /* Order HPTE updates vs. mmu_ready */
1942         smp_wmb();
1943         kvm->arch.mmu_ready = mmu_ready;
1944         mutex_unlock(&kvm->arch.mmu_setup_lock);
1945 
1946         if (err)
1947                 return err;
1948         return nb;
1949 }
1950 
1951 static int kvm_htab_release(struct inode *inode, struct file *filp)
1952 {
1953         struct kvm_htab_ctx *ctx = filp->private_data;
1954 
1955         filp->private_data = NULL;
1956         if (!(ctx->flags & KVM_GET_HTAB_WRITE))
1957                 atomic_dec(&ctx->kvm->arch.hpte_mod_interest);
1958         kvm_put_kvm(ctx->kvm);
1959         kfree(ctx);
1960         return 0;
1961 }
1962 
1963 static const struct file_operations kvm_htab_fops = {
1964         .read           = kvm_htab_read,
1965         .write          = kvm_htab_write,
1966         .llseek         = default_llseek,
1967         .release        = kvm_htab_release,
1968 };
1969 
1970 int kvm_vm_ioctl_get_htab_fd(struct kvm *kvm, struct kvm_get_htab_fd *ghf)
1971 {
1972         int ret;
1973         struct kvm_htab_ctx *ctx;
1974         int rwflag;
1975 
1976         /* reject flags we don't recognize */
1977         if (ghf->flags & ~(KVM_GET_HTAB_BOLTED_ONLY | KVM_GET_HTAB_WRITE))
1978                 return -EINVAL;
1979         ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
1980         if (!ctx)
1981                 return -ENOMEM;
1982         kvm_get_kvm(kvm);
1983         ctx->kvm = kvm;
1984         ctx->index = ghf->start_index;
1985         ctx->flags = ghf->flags;
1986         ctx->first_pass = 1;
1987 
1988         rwflag = (ghf->flags & KVM_GET_HTAB_WRITE) ? O_WRONLY : O_RDONLY;
1989         ret = anon_inode_getfd("kvm-htab", &kvm_htab_fops, ctx, rwflag | O_CLOEXEC);
1990         if (ret < 0) {
1991                 kfree(ctx);
1992                 kvm_put_kvm_no_destroy(kvm);
1993                 return ret;
1994         }
1995 
1996         if (rwflag == O_RDONLY) {
1997                 mutex_lock(&kvm->slots_lock);
1998                 atomic_inc(&kvm->arch.hpte_mod_interest);
1999                 /* make sure kvmppc_do_h_enter etc. see the increment */
2000                 synchronize_srcu_expedited(&kvm->srcu);
2001                 mutex_unlock(&kvm->slots_lock);
2002         }
2003 
2004         return ret;
2005 }
2006 
2007 struct debugfs_htab_state {
2008         struct kvm      *kvm;
2009         struct mutex    mutex;
2010         unsigned long   hpt_index;
2011         int             chars_left;
2012         int             buf_index;
2013         char            buf[64];
2014 };
2015 
2016 static int debugfs_htab_open(struct inode *inode, struct file *file)
2017 {
2018         struct kvm *kvm = inode->i_private;
2019         struct debugfs_htab_state *p;
2020 
2021         p = kzalloc(sizeof(*p), GFP_KERNEL);
2022         if (!p)
2023                 return -ENOMEM;
2024 
2025         kvm_get_kvm(kvm);
2026         p->kvm = kvm;
2027         mutex_init(&p->mutex);
2028         file->private_data = p;
2029 
2030         return nonseekable_open(inode, file);
2031 }
2032 
2033 static int debugfs_htab_release(struct inode *inode, struct file *file)
2034 {
2035         struct debugfs_htab_state *p = file->private_data;
2036 
2037         kvm_put_kvm(p->kvm);
2038         kfree(p);
2039         return 0;
2040 }
2041 
2042 static ssize_t debugfs_htab_read(struct file *file, char __user *buf,
2043                                  size_t len, loff_t *ppos)
2044 {
2045         struct debugfs_htab_state *p = file->private_data;
2046         ssize_t ret, r;
2047         unsigned long i, n;
2048         unsigned long v, hr, gr;
2049         struct kvm *kvm;
2050         __be64 *hptp;
2051 
2052         kvm = p->kvm;
2053         if (kvm_is_radix(kvm))
2054                 return 0;
2055 
2056         ret = mutex_lock_interruptible(&p->mutex);
2057         if (ret)
2058                 return ret;
2059 
2060         if (p->chars_left) {
2061                 n = p->chars_left;
2062                 if (n > len)
2063                         n = len;
2064                 r = copy_to_user(buf, p->buf + p->buf_index, n);
2065                 n -= r;
2066                 p->chars_left -= n;
2067                 p->buf_index += n;
2068                 buf += n;
2069                 len -= n;
2070                 ret = n;
2071                 if (r) {
2072                         if (!n)
2073                                 ret = -EFAULT;
2074                         goto out;
2075                 }
2076         }
2077 
2078         i = p->hpt_index;
2079         hptp = (__be64 *)(kvm->arch.hpt.virt + (i * HPTE_SIZE));
2080         for (; len != 0 && i < kvmppc_hpt_npte(&kvm->arch.hpt);
2081              ++i, hptp += 2) {
2082                 if (!(be64_to_cpu(hptp[0]) & (HPTE_V_VALID | HPTE_V_ABSENT)))
2083                         continue;
2084 
2085                 /* lock the HPTE so it's stable and read it */
2086                 preempt_disable();
2087                 while (!try_lock_hpte(hptp, HPTE_V_HVLOCK))
2088                         cpu_relax();
2089                 v = be64_to_cpu(hptp[0]) & ~HPTE_V_HVLOCK;
2090                 hr = be64_to_cpu(hptp[1]);
2091                 gr = kvm->arch.hpt.rev[i].guest_rpte;
2092                 unlock_hpte(hptp, v);
2093                 preempt_enable();
2094 
2095                 if (!(v & (HPTE_V_VALID | HPTE_V_ABSENT)))
2096                         continue;
2097 
2098                 n = scnprintf(p->buf, sizeof(p->buf),
2099                               "%6lx %.16lx %.16lx %.16lx\n",
2100                               i, v, hr, gr);
2101                 p->chars_left = n;
2102                 if (n > len)
2103                         n = len;
2104                 r = copy_to_user(buf, p->buf, n);
2105                 n -= r;
2106                 p->chars_left -= n;
2107                 p->buf_index = n;
2108                 buf += n;
2109                 len -= n;
2110                 ret += n;
2111                 if (r) {
2112                         if (!ret)
2113                                 ret = -EFAULT;
2114                         goto out;
2115                 }
2116         }
2117         p->hpt_index = i;
2118 
2119  out:
2120         mutex_unlock(&p->mutex);
2121         return ret;
2122 }
2123 
2124 static ssize_t debugfs_htab_write(struct file *file, const char __user *buf,
2125                            size_t len, loff_t *ppos)
2126 {
2127         return -EACCES;
2128 }
2129 
2130 static const struct file_operations debugfs_htab_fops = {
2131         .owner   = THIS_MODULE,
2132         .open    = debugfs_htab_open,
2133         .release = debugfs_htab_release,
2134         .read    = debugfs_htab_read,
2135         .write   = debugfs_htab_write,
2136         .llseek  = generic_file_llseek,
2137 };
2138 
2139 void kvmppc_mmu_debugfs_init(struct kvm *kvm)
2140 {
2141         kvm->arch.htab_dentry = debugfs_create_file("htab", 0400,
2142                                                     kvm->arch.debugfs_dir, kvm,
2143                                                     &debugfs_htab_fops);
2144 }
2145 
2146 void kvmppc_mmu_book3s_hv_init(struct kvm_vcpu *vcpu)
2147 {
2148         struct kvmppc_mmu *mmu = &vcpu->arch.mmu;
2149 
2150         vcpu->arch.slb_nr = 32;         /* POWER7/POWER8 */
2151 
2152         mmu->xlate = kvmppc_mmu_book3s_64_hv_xlate;
2153 
2154         vcpu->arch.hflags |= BOOK3S_HFLAG_SLB;
2155 }
2156 

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