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TOMOYO Linux Cross Reference
Linux/arch/powerpc/kvm/book3s_64_mmu_hv.c

Version: ~ [ linux-5.10-rc6 ] ~ [ linux-5.9.12 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.81 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.161 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.210 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.247 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.247 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.85 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * This program is free software; you can redistribute it and/or modify
  3  * it under the terms of the GNU General Public License, version 2, as
  4  * published by the Free Software Foundation.
  5  *
  6  * This program is distributed in the hope that it will be useful,
  7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  9  * GNU General Public License for more details.
 10  *
 11  * You should have received a copy of the GNU General Public License
 12  * along with this program; if not, write to the Free Software
 13  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 14  *
 15  * Copyright 2010 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
 16  */
 17 
 18 #include <linux/types.h>
 19 #include <linux/string.h>
 20 #include <linux/kvm.h>
 21 #include <linux/kvm_host.h>
 22 #include <linux/highmem.h>
 23 #include <linux/gfp.h>
 24 #include <linux/slab.h>
 25 #include <linux/hugetlb.h>
 26 #include <linux/vmalloc.h>
 27 #include <linux/srcu.h>
 28 #include <linux/anon_inodes.h>
 29 #include <linux/file.h>
 30 
 31 #include <asm/tlbflush.h>
 32 #include <asm/kvm_ppc.h>
 33 #include <asm/kvm_book3s.h>
 34 #include <asm/mmu-hash64.h>
 35 #include <asm/hvcall.h>
 36 #include <asm/synch.h>
 37 #include <asm/ppc-opcode.h>
 38 #include <asm/cputable.h>
 39 
 40 #include "trace_hv.h"
 41 
 42 /* Power architecture requires HPT is at least 256kB */
 43 #define PPC_MIN_HPT_ORDER       18
 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 static void kvmppc_rmap_reset(struct kvm *kvm);
 49 
 50 long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp)
 51 {
 52         unsigned long hpt = 0;
 53         struct revmap_entry *rev;
 54         struct page *page = NULL;
 55         long order = KVM_DEFAULT_HPT_ORDER;
 56 
 57         if (htab_orderp) {
 58                 order = *htab_orderp;
 59                 if (order < PPC_MIN_HPT_ORDER)
 60                         order = PPC_MIN_HPT_ORDER;
 61         }
 62 
 63         kvm->arch.hpt_cma_alloc = 0;
 64         page = kvm_alloc_hpt(1ul << (order - PAGE_SHIFT));
 65         if (page) {
 66                 hpt = (unsigned long)pfn_to_kaddr(page_to_pfn(page));
 67                 memset((void *)hpt, 0, (1ul << order));
 68                 kvm->arch.hpt_cma_alloc = 1;
 69         }
 70 
 71         /* Lastly try successively smaller sizes from the page allocator */
 72         while (!hpt && order > PPC_MIN_HPT_ORDER) {
 73                 hpt = __get_free_pages(GFP_KERNEL|__GFP_ZERO|__GFP_REPEAT|
 74                                        __GFP_NOWARN, order - PAGE_SHIFT);
 75                 if (!hpt)
 76                         --order;
 77         }
 78 
 79         if (!hpt)
 80                 return -ENOMEM;
 81 
 82         kvm->arch.hpt_virt = hpt;
 83         kvm->arch.hpt_order = order;
 84         /* HPTEs are 2**4 bytes long */
 85         kvm->arch.hpt_npte = 1ul << (order - 4);
 86         /* 128 (2**7) bytes in each HPTEG */
 87         kvm->arch.hpt_mask = (1ul << (order - 7)) - 1;
 88 
 89         /* Allocate reverse map array */
 90         rev = vmalloc(sizeof(struct revmap_entry) * kvm->arch.hpt_npte);
 91         if (!rev) {
 92                 pr_err("kvmppc_alloc_hpt: Couldn't alloc reverse map array\n");
 93                 goto out_freehpt;
 94         }
 95         kvm->arch.revmap = rev;
 96         kvm->arch.sdr1 = __pa(hpt) | (order - 18);
 97 
 98         pr_info("KVM guest htab at %lx (order %ld), LPID %x\n",
 99                 hpt, order, kvm->arch.lpid);
100 
101         if (htab_orderp)
102                 *htab_orderp = order;
103         return 0;
104 
105  out_freehpt:
106         if (kvm->arch.hpt_cma_alloc)
107                 kvm_release_hpt(page, 1 << (order - PAGE_SHIFT));
108         else
109                 free_pages(hpt, order - PAGE_SHIFT);
110         return -ENOMEM;
111 }
112 
113 long kvmppc_alloc_reset_hpt(struct kvm *kvm, u32 *htab_orderp)
114 {
115         long err = -EBUSY;
116         long order;
117 
118         mutex_lock(&kvm->lock);
119         if (kvm->arch.rma_setup_done) {
120                 kvm->arch.rma_setup_done = 0;
121                 /* order rma_setup_done vs. vcpus_running */
122                 smp_mb();
123                 if (atomic_read(&kvm->arch.vcpus_running)) {
124                         kvm->arch.rma_setup_done = 1;
125                         goto out;
126                 }
127         }
128         if (kvm->arch.hpt_virt) {
129                 order = kvm->arch.hpt_order;
130                 /* Set the entire HPT to 0, i.e. invalid HPTEs */
131                 memset((void *)kvm->arch.hpt_virt, 0, 1ul << order);
132                 /*
133                  * Reset all the reverse-mapping chains for all memslots
134                  */
135                 kvmppc_rmap_reset(kvm);
136                 /* Ensure that each vcpu will flush its TLB on next entry. */
137                 cpumask_setall(&kvm->arch.need_tlb_flush);
138                 *htab_orderp = order;
139                 err = 0;
140         } else {
141                 err = kvmppc_alloc_hpt(kvm, htab_orderp);
142                 order = *htab_orderp;
143         }
144  out:
145         mutex_unlock(&kvm->lock);
146         return err;
147 }
148 
149 void kvmppc_free_hpt(struct kvm *kvm)
150 {
151         kvmppc_free_lpid(kvm->arch.lpid);
152         vfree(kvm->arch.revmap);
153         if (kvm->arch.hpt_cma_alloc)
154                 kvm_release_hpt(virt_to_page(kvm->arch.hpt_virt),
155                                 1 << (kvm->arch.hpt_order - PAGE_SHIFT));
156         else
157                 free_pages(kvm->arch.hpt_virt,
158                            kvm->arch.hpt_order - PAGE_SHIFT);
159 }
160 
161 /* Bits in first HPTE dword for pagesize 4k, 64k or 16M */
162 static inline unsigned long hpte0_pgsize_encoding(unsigned long pgsize)
163 {
164         return (pgsize > 0x1000) ? HPTE_V_LARGE : 0;
165 }
166 
167 /* Bits in second HPTE dword for pagesize 4k, 64k or 16M */
168 static inline unsigned long hpte1_pgsize_encoding(unsigned long pgsize)
169 {
170         return (pgsize == 0x10000) ? 0x1000 : 0;
171 }
172 
173 void kvmppc_map_vrma(struct kvm_vcpu *vcpu, struct kvm_memory_slot *memslot,
174                      unsigned long porder)
175 {
176         unsigned long i;
177         unsigned long npages;
178         unsigned long hp_v, hp_r;
179         unsigned long addr, hash;
180         unsigned long psize;
181         unsigned long hp0, hp1;
182         unsigned long idx_ret;
183         long ret;
184         struct kvm *kvm = vcpu->kvm;
185 
186         psize = 1ul << porder;
187         npages = memslot->npages >> (porder - PAGE_SHIFT);
188 
189         /* VRMA can't be > 1TB */
190         if (npages > 1ul << (40 - porder))
191                 npages = 1ul << (40 - porder);
192         /* Can't use more than 1 HPTE per HPTEG */
193         if (npages > kvm->arch.hpt_mask + 1)
194                 npages = kvm->arch.hpt_mask + 1;
195 
196         hp0 = HPTE_V_1TB_SEG | (VRMA_VSID << (40 - 16)) |
197                 HPTE_V_BOLTED | hpte0_pgsize_encoding(psize);
198         hp1 = hpte1_pgsize_encoding(psize) |
199                 HPTE_R_R | HPTE_R_C | HPTE_R_M | PP_RWXX;
200 
201         for (i = 0; i < npages; ++i) {
202                 addr = i << porder;
203                 /* can't use hpt_hash since va > 64 bits */
204                 hash = (i ^ (VRMA_VSID ^ (VRMA_VSID << 25))) & kvm->arch.hpt_mask;
205                 /*
206                  * We assume that the hash table is empty and no
207                  * vcpus are using it at this stage.  Since we create
208                  * at most one HPTE per HPTEG, we just assume entry 7
209                  * is available and use it.
210                  */
211                 hash = (hash << 3) + 7;
212                 hp_v = hp0 | ((addr >> 16) & ~0x7fUL);
213                 hp_r = hp1 | addr;
214                 ret = kvmppc_virtmode_do_h_enter(kvm, H_EXACT, hash, hp_v, hp_r,
215                                                  &idx_ret);
216                 if (ret != H_SUCCESS) {
217                         pr_err("KVM: map_vrma at %lx failed, ret=%ld\n",
218                                addr, ret);
219                         break;
220                 }
221         }
222 }
223 
224 int kvmppc_mmu_hv_init(void)
225 {
226         unsigned long host_lpid, rsvd_lpid;
227 
228         if (!cpu_has_feature(CPU_FTR_HVMODE))
229                 return -EINVAL;
230 
231         /* POWER7 has 10-bit LPIDs (12-bit in POWER8) */
232         host_lpid = mfspr(SPRN_LPID);
233         rsvd_lpid = LPID_RSVD;
234 
235         kvmppc_init_lpid(rsvd_lpid + 1);
236 
237         kvmppc_claim_lpid(host_lpid);
238         /* rsvd_lpid is reserved for use in partition switching */
239         kvmppc_claim_lpid(rsvd_lpid);
240 
241         return 0;
242 }
243 
244 static void kvmppc_mmu_book3s_64_hv_reset_msr(struct kvm_vcpu *vcpu)
245 {
246         unsigned long msr = vcpu->arch.intr_msr;
247 
248         /* If transactional, change to suspend mode on IRQ delivery */
249         if (MSR_TM_TRANSACTIONAL(vcpu->arch.shregs.msr))
250                 msr |= MSR_TS_S;
251         else
252                 msr |= vcpu->arch.shregs.msr & MSR_TS_MASK;
253         kvmppc_set_msr(vcpu, msr);
254 }
255 
256 long kvmppc_virtmode_do_h_enter(struct kvm *kvm, unsigned long flags,
257                                 long pte_index, unsigned long pteh,
258                                 unsigned long ptel, unsigned long *pte_idx_ret)
259 {
260         long ret;
261 
262         /* Protect linux PTE lookup from page table destruction */
263         rcu_read_lock_sched();  /* this disables preemption too */
264         ret = kvmppc_do_h_enter(kvm, flags, pte_index, pteh, ptel,
265                                 current->mm->pgd, false, pte_idx_ret);
266         rcu_read_unlock_sched();
267         if (ret == H_TOO_HARD) {
268                 /* this can't happen */
269                 pr_err("KVM: Oops, kvmppc_h_enter returned too hard!\n");
270                 ret = H_RESOURCE;       /* or something */
271         }
272         return ret;
273 
274 }
275 
276 static struct kvmppc_slb *kvmppc_mmu_book3s_hv_find_slbe(struct kvm_vcpu *vcpu,
277                                                          gva_t eaddr)
278 {
279         u64 mask;
280         int i;
281 
282         for (i = 0; i < vcpu->arch.slb_nr; i++) {
283                 if (!(vcpu->arch.slb[i].orige & SLB_ESID_V))
284                         continue;
285 
286                 if (vcpu->arch.slb[i].origv & SLB_VSID_B_1T)
287                         mask = ESID_MASK_1T;
288                 else
289                         mask = ESID_MASK;
290 
291                 if (((vcpu->arch.slb[i].orige ^ eaddr) & mask) == 0)
292                         return &vcpu->arch.slb[i];
293         }
294         return NULL;
295 }
296 
297 static unsigned long kvmppc_mmu_get_real_addr(unsigned long v, unsigned long r,
298                         unsigned long ea)
299 {
300         unsigned long ra_mask;
301 
302         ra_mask = hpte_page_size(v, r) - 1;
303         return (r & HPTE_R_RPN & ~ra_mask) | (ea & ra_mask);
304 }
305 
306 static int kvmppc_mmu_book3s_64_hv_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
307                         struct kvmppc_pte *gpte, bool data, bool iswrite)
308 {
309         struct kvm *kvm = vcpu->kvm;
310         struct kvmppc_slb *slbe;
311         unsigned long slb_v;
312         unsigned long pp, key;
313         unsigned long v, gr;
314         __be64 *hptep;
315         int index;
316         int virtmode = vcpu->arch.shregs.msr & (data ? MSR_DR : MSR_IR);
317 
318         /* Get SLB entry */
319         if (virtmode) {
320                 slbe = kvmppc_mmu_book3s_hv_find_slbe(vcpu, eaddr);
321                 if (!slbe)
322                         return -EINVAL;
323                 slb_v = slbe->origv;
324         } else {
325                 /* real mode access */
326                 slb_v = vcpu->kvm->arch.vrma_slb_v;
327         }
328 
329         preempt_disable();
330         /* Find the HPTE in the hash table */
331         index = kvmppc_hv_find_lock_hpte(kvm, eaddr, slb_v,
332                                          HPTE_V_VALID | HPTE_V_ABSENT);
333         if (index < 0) {
334                 preempt_enable();
335                 return -ENOENT;
336         }
337         hptep = (__be64 *)(kvm->arch.hpt_virt + (index << 4));
338         v = be64_to_cpu(hptep[0]) & ~HPTE_V_HVLOCK;
339         gr = kvm->arch.revmap[index].guest_rpte;
340 
341         /* Unlock the HPTE */
342         asm volatile("lwsync" : : : "memory");
343         hptep[0] = cpu_to_be64(v);
344         preempt_enable();
345 
346         gpte->eaddr = eaddr;
347         gpte->vpage = ((v & HPTE_V_AVPN) << 4) | ((eaddr >> 12) & 0xfff);
348 
349         /* Get PP bits and key for permission check */
350         pp = gr & (HPTE_R_PP0 | HPTE_R_PP);
351         key = (vcpu->arch.shregs.msr & MSR_PR) ? SLB_VSID_KP : SLB_VSID_KS;
352         key &= slb_v;
353 
354         /* Calculate permissions */
355         gpte->may_read = hpte_read_permission(pp, key);
356         gpte->may_write = hpte_write_permission(pp, key);
357         gpte->may_execute = gpte->may_read && !(gr & (HPTE_R_N | HPTE_R_G));
358 
359         /* Storage key permission check for POWER7 */
360         if (data && virtmode) {
361                 int amrfield = hpte_get_skey_perm(gr, vcpu->arch.amr);
362                 if (amrfield & 1)
363                         gpte->may_read = 0;
364                 if (amrfield & 2)
365                         gpte->may_write = 0;
366         }
367 
368         /* Get the guest physical address */
369         gpte->raddr = kvmppc_mmu_get_real_addr(v, gr, eaddr);
370         return 0;
371 }
372 
373 /*
374  * Quick test for whether an instruction is a load or a store.
375  * If the instruction is a load or a store, then this will indicate
376  * which it is, at least on server processors.  (Embedded processors
377  * have some external PID instructions that don't follow the rule
378  * embodied here.)  If the instruction isn't a load or store, then
379  * this doesn't return anything useful.
380  */
381 static int instruction_is_store(unsigned int instr)
382 {
383         unsigned int mask;
384 
385         mask = 0x10000000;
386         if ((instr & 0xfc000000) == 0x7c000000)
387                 mask = 0x100;           /* major opcode 31 */
388         return (instr & mask) != 0;
389 }
390 
391 static int kvmppc_hv_emulate_mmio(struct kvm_run *run, struct kvm_vcpu *vcpu,
392                                   unsigned long gpa, gva_t ea, int is_store)
393 {
394         u32 last_inst;
395 
396         /*
397          * If we fail, we just return to the guest and try executing it again.
398          */
399         if (kvmppc_get_last_inst(vcpu, INST_GENERIC, &last_inst) !=
400                 EMULATE_DONE)
401                 return RESUME_GUEST;
402 
403         /*
404          * WARNING: We do not know for sure whether the instruction we just
405          * read from memory is the same that caused the fault in the first
406          * place.  If the instruction we read is neither an load or a store,
407          * then it can't access memory, so we don't need to worry about
408          * enforcing access permissions.  So, assuming it is a load or
409          * store, we just check that its direction (load or store) is
410          * consistent with the original fault, since that's what we
411          * checked the access permissions against.  If there is a mismatch
412          * we just return and retry the instruction.
413          */
414 
415         if (instruction_is_store(last_inst) != !!is_store)
416                 return RESUME_GUEST;
417 
418         /*
419          * Emulated accesses are emulated by looking at the hash for
420          * translation once, then performing the access later. The
421          * translation could be invalidated in the meantime in which
422          * point performing the subsequent memory access on the old
423          * physical address could possibly be a security hole for the
424          * guest (but not the host).
425          *
426          * This is less of an issue for MMIO stores since they aren't
427          * globally visible. It could be an issue for MMIO loads to
428          * a certain extent but we'll ignore it for now.
429          */
430 
431         vcpu->arch.paddr_accessed = gpa;
432         vcpu->arch.vaddr_accessed = ea;
433         return kvmppc_emulate_mmio(run, vcpu);
434 }
435 
436 int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
437                                 unsigned long ea, unsigned long dsisr)
438 {
439         struct kvm *kvm = vcpu->kvm;
440         unsigned long hpte[3], r;
441         __be64 *hptep;
442         unsigned long mmu_seq, psize, pte_size;
443         unsigned long gpa_base, gfn_base;
444         unsigned long gpa, gfn, hva, pfn;
445         struct kvm_memory_slot *memslot;
446         unsigned long *rmap;
447         struct revmap_entry *rev;
448         struct page *page, *pages[1];
449         long index, ret, npages;
450         unsigned long is_io;
451         unsigned int writing, write_ok;
452         struct vm_area_struct *vma;
453         unsigned long rcbits;
454 
455         /*
456          * Real-mode code has already searched the HPT and found the
457          * entry we're interested in.  Lock the entry and check that
458          * it hasn't changed.  If it has, just return and re-execute the
459          * instruction.
460          */
461         if (ea != vcpu->arch.pgfault_addr)
462                 return RESUME_GUEST;
463         index = vcpu->arch.pgfault_index;
464         hptep = (__be64 *)(kvm->arch.hpt_virt + (index << 4));
465         rev = &kvm->arch.revmap[index];
466         preempt_disable();
467         while (!try_lock_hpte(hptep, HPTE_V_HVLOCK))
468                 cpu_relax();
469         hpte[0] = be64_to_cpu(hptep[0]) & ~HPTE_V_HVLOCK;
470         hpte[1] = be64_to_cpu(hptep[1]);
471         hpte[2] = r = rev->guest_rpte;
472         asm volatile("lwsync" : : : "memory");
473         hptep[0] = cpu_to_be64(hpte[0]);
474         preempt_enable();
475 
476         if (hpte[0] != vcpu->arch.pgfault_hpte[0] ||
477             hpte[1] != vcpu->arch.pgfault_hpte[1])
478                 return RESUME_GUEST;
479 
480         /* Translate the logical address and get the page */
481         psize = hpte_page_size(hpte[0], r);
482         gpa_base = r & HPTE_R_RPN & ~(psize - 1);
483         gfn_base = gpa_base >> PAGE_SHIFT;
484         gpa = gpa_base | (ea & (psize - 1));
485         gfn = gpa >> PAGE_SHIFT;
486         memslot = gfn_to_memslot(kvm, gfn);
487 
488         trace_kvm_page_fault_enter(vcpu, hpte, memslot, ea, dsisr);
489 
490         /* No memslot means it's an emulated MMIO region */
491         if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID))
492                 return kvmppc_hv_emulate_mmio(run, vcpu, gpa, ea,
493                                               dsisr & DSISR_ISSTORE);
494 
495         /*
496          * This should never happen, because of the slot_is_aligned()
497          * check in kvmppc_do_h_enter().
498          */
499         if (gfn_base < memslot->base_gfn)
500                 return -EFAULT;
501 
502         /* used to check for invalidations in progress */
503         mmu_seq = kvm->mmu_notifier_seq;
504         smp_rmb();
505 
506         ret = -EFAULT;
507         is_io = 0;
508         pfn = 0;
509         page = NULL;
510         pte_size = PAGE_SIZE;
511         writing = (dsisr & DSISR_ISSTORE) != 0;
512         /* If writing != 0, then the HPTE must allow writing, if we get here */
513         write_ok = writing;
514         hva = gfn_to_hva_memslot(memslot, gfn);
515         npages = get_user_pages_fast(hva, 1, writing, pages);
516         if (npages < 1) {
517                 /* Check if it's an I/O mapping */
518                 down_read(&current->mm->mmap_sem);
519                 vma = find_vma(current->mm, hva);
520                 if (vma && vma->vm_start <= hva && hva + psize <= vma->vm_end &&
521                     (vma->vm_flags & VM_PFNMAP)) {
522                         pfn = vma->vm_pgoff +
523                                 ((hva - vma->vm_start) >> PAGE_SHIFT);
524                         pte_size = psize;
525                         is_io = hpte_cache_bits(pgprot_val(vma->vm_page_prot));
526                         write_ok = vma->vm_flags & VM_WRITE;
527                 }
528                 up_read(&current->mm->mmap_sem);
529                 if (!pfn)
530                         goto out_put;
531         } else {
532                 page = pages[0];
533                 pfn = page_to_pfn(page);
534                 if (PageHuge(page)) {
535                         page = compound_head(page);
536                         pte_size <<= compound_order(page);
537                 }
538                 /* if the guest wants write access, see if that is OK */
539                 if (!writing && hpte_is_writable(r)) {
540                         unsigned int hugepage_shift;
541                         pte_t *ptep, pte;
542 
543                         /*
544                          * We need to protect against page table destruction
545                          * while looking up and updating the pte.
546                          */
547                         rcu_read_lock_sched();
548                         ptep = find_linux_pte_or_hugepte(current->mm->pgd,
549                                                          hva, &hugepage_shift);
550                         if (ptep) {
551                                 pte = kvmppc_read_update_linux_pte(ptep, 1,
552                                                            hugepage_shift);
553                                 if (pte_write(pte))
554                                         write_ok = 1;
555                         }
556                         rcu_read_unlock_sched();
557                 }
558         }
559 
560         if (psize > pte_size)
561                 goto out_put;
562 
563         /* Check WIMG vs. the actual page we're accessing */
564         if (!hpte_cache_flags_ok(r, is_io)) {
565                 if (is_io)
566                         goto out_put;
567 
568                 /*
569                  * Allow guest to map emulated device memory as
570                  * uncacheable, but actually make it cacheable.
571                  */
572                 r = (r & ~(HPTE_R_W|HPTE_R_I|HPTE_R_G)) | HPTE_R_M;
573         }
574 
575         /*
576          * Set the HPTE to point to pfn.
577          * Since the pfn is at PAGE_SIZE granularity, make sure we
578          * don't mask out lower-order bits if psize < PAGE_SIZE.
579          */
580         if (psize < PAGE_SIZE)
581                 psize = PAGE_SIZE;
582         r = (r & ~(HPTE_R_PP0 - psize)) | ((pfn << PAGE_SHIFT) & ~(psize - 1));
583         if (hpte_is_writable(r) && !write_ok)
584                 r = hpte_make_readonly(r);
585         ret = RESUME_GUEST;
586         preempt_disable();
587         while (!try_lock_hpte(hptep, HPTE_V_HVLOCK))
588                 cpu_relax();
589         if ((be64_to_cpu(hptep[0]) & ~HPTE_V_HVLOCK) != hpte[0] ||
590                 be64_to_cpu(hptep[1]) != hpte[1] ||
591                 rev->guest_rpte != hpte[2])
592                 /* HPTE has been changed under us; let the guest retry */
593                 goto out_unlock;
594         hpte[0] = (hpte[0] & ~HPTE_V_ABSENT) | HPTE_V_VALID;
595 
596         /* Always put the HPTE in the rmap chain for the page base address */
597         rmap = &memslot->arch.rmap[gfn_base - memslot->base_gfn];
598         lock_rmap(rmap);
599 
600         /* Check if we might have been invalidated; let the guest retry if so */
601         ret = RESUME_GUEST;
602         if (mmu_notifier_retry(vcpu->kvm, mmu_seq)) {
603                 unlock_rmap(rmap);
604                 goto out_unlock;
605         }
606 
607         /* Only set R/C in real HPTE if set in both *rmap and guest_rpte */
608         rcbits = *rmap >> KVMPPC_RMAP_RC_SHIFT;
609         r &= rcbits | ~(HPTE_R_R | HPTE_R_C);
610 
611         if (be64_to_cpu(hptep[0]) & HPTE_V_VALID) {
612                 /* HPTE was previously valid, so we need to invalidate it */
613                 unlock_rmap(rmap);
614                 hptep[0] |= cpu_to_be64(HPTE_V_ABSENT);
615                 kvmppc_invalidate_hpte(kvm, hptep, index);
616                 /* don't lose previous R and C bits */
617                 r |= be64_to_cpu(hptep[1]) & (HPTE_R_R | HPTE_R_C);
618         } else {
619                 kvmppc_add_revmap_chain(kvm, rev, rmap, index, 0);
620         }
621 
622         hptep[1] = cpu_to_be64(r);
623         eieio();
624         hptep[0] = cpu_to_be64(hpte[0]);
625         asm volatile("ptesync" : : : "memory");
626         preempt_enable();
627         if (page && hpte_is_writable(r))
628                 SetPageDirty(page);
629 
630  out_put:
631         trace_kvm_page_fault_exit(vcpu, hpte, ret);
632 
633         if (page) {
634                 /*
635                  * We drop pages[0] here, not page because page might
636                  * have been set to the head page of a compound, but
637                  * we have to drop the reference on the correct tail
638                  * page to match the get inside gup()
639                  */
640                 put_page(pages[0]);
641         }
642         return ret;
643 
644  out_unlock:
645         hptep[0] &= ~cpu_to_be64(HPTE_V_HVLOCK);
646         preempt_enable();
647         goto out_put;
648 }
649 
650 static void kvmppc_rmap_reset(struct kvm *kvm)
651 {
652         struct kvm_memslots *slots;
653         struct kvm_memory_slot *memslot;
654         int srcu_idx;
655 
656         srcu_idx = srcu_read_lock(&kvm->srcu);
657         slots = kvm->memslots;
658         kvm_for_each_memslot(memslot, slots) {
659                 /*
660                  * This assumes it is acceptable to lose reference and
661                  * change bits across a reset.
662                  */
663                 memset(memslot->arch.rmap, 0,
664                        memslot->npages * sizeof(*memslot->arch.rmap));
665         }
666         srcu_read_unlock(&kvm->srcu, srcu_idx);
667 }
668 
669 static int kvm_handle_hva_range(struct kvm *kvm,
670                                 unsigned long start,
671                                 unsigned long end,
672                                 int (*handler)(struct kvm *kvm,
673                                                unsigned long *rmapp,
674                                                unsigned long gfn))
675 {
676         int ret;
677         int retval = 0;
678         struct kvm_memslots *slots;
679         struct kvm_memory_slot *memslot;
680 
681         slots = kvm_memslots(kvm);
682         kvm_for_each_memslot(memslot, slots) {
683                 unsigned long hva_start, hva_end;
684                 gfn_t gfn, gfn_end;
685 
686                 hva_start = max(start, memslot->userspace_addr);
687                 hva_end = min(end, memslot->userspace_addr +
688                                         (memslot->npages << PAGE_SHIFT));
689                 if (hva_start >= hva_end)
690                         continue;
691                 /*
692                  * {gfn(page) | page intersects with [hva_start, hva_end)} =
693                  * {gfn, gfn+1, ..., gfn_end-1}.
694                  */
695                 gfn = hva_to_gfn_memslot(hva_start, memslot);
696                 gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot);
697 
698                 for (; gfn < gfn_end; ++gfn) {
699                         gfn_t gfn_offset = gfn - memslot->base_gfn;
700 
701                         ret = handler(kvm, &memslot->arch.rmap[gfn_offset], gfn);
702                         retval |= ret;
703                 }
704         }
705 
706         return retval;
707 }
708 
709 static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
710                           int (*handler)(struct kvm *kvm, unsigned long *rmapp,
711                                          unsigned long gfn))
712 {
713         return kvm_handle_hva_range(kvm, hva, hva + 1, handler);
714 }
715 
716 static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp,
717                            unsigned long gfn)
718 {
719         struct revmap_entry *rev = kvm->arch.revmap;
720         unsigned long h, i, j;
721         __be64 *hptep;
722         unsigned long ptel, psize, rcbits;
723 
724         for (;;) {
725                 lock_rmap(rmapp);
726                 if (!(*rmapp & KVMPPC_RMAP_PRESENT)) {
727                         unlock_rmap(rmapp);
728                         break;
729                 }
730 
731                 /*
732                  * To avoid an ABBA deadlock with the HPTE lock bit,
733                  * we can't spin on the HPTE lock while holding the
734                  * rmap chain lock.
735                  */
736                 i = *rmapp & KVMPPC_RMAP_INDEX;
737                 hptep = (__be64 *) (kvm->arch.hpt_virt + (i << 4));
738                 if (!try_lock_hpte(hptep, HPTE_V_HVLOCK)) {
739                         /* unlock rmap before spinning on the HPTE lock */
740                         unlock_rmap(rmapp);
741                         while (be64_to_cpu(hptep[0]) & HPTE_V_HVLOCK)
742                                 cpu_relax();
743                         continue;
744                 }
745                 j = rev[i].forw;
746                 if (j == i) {
747                         /* chain is now empty */
748                         *rmapp &= ~(KVMPPC_RMAP_PRESENT | KVMPPC_RMAP_INDEX);
749                 } else {
750                         /* remove i from chain */
751                         h = rev[i].back;
752                         rev[h].forw = j;
753                         rev[j].back = h;
754                         rev[i].forw = rev[i].back = i;
755                         *rmapp = (*rmapp & ~KVMPPC_RMAP_INDEX) | j;
756                 }
757 
758                 /* Now check and modify the HPTE */
759                 ptel = rev[i].guest_rpte;
760                 psize = hpte_page_size(be64_to_cpu(hptep[0]), ptel);
761                 if ((be64_to_cpu(hptep[0]) & HPTE_V_VALID) &&
762                     hpte_rpn(ptel, psize) == gfn) {
763                         hptep[0] |= cpu_to_be64(HPTE_V_ABSENT);
764                         kvmppc_invalidate_hpte(kvm, hptep, i);
765                         /* Harvest R and C */
766                         rcbits = be64_to_cpu(hptep[1]) & (HPTE_R_R | HPTE_R_C);
767                         *rmapp |= rcbits << KVMPPC_RMAP_RC_SHIFT;
768                         if (rcbits & ~rev[i].guest_rpte) {
769                                 rev[i].guest_rpte = ptel | rcbits;
770                                 note_hpte_modification(kvm, &rev[i]);
771                         }
772                 }
773                 unlock_rmap(rmapp);
774                 hptep[0] &= ~cpu_to_be64(HPTE_V_HVLOCK);
775         }
776         return 0;
777 }
778 
779 int kvm_unmap_hva_hv(struct kvm *kvm, unsigned long hva)
780 {
781         kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);
782         return 0;
783 }
784 
785 int kvm_unmap_hva_range_hv(struct kvm *kvm, unsigned long start, unsigned long end)
786 {
787         kvm_handle_hva_range(kvm, start, end, kvm_unmap_rmapp);
788         return 0;
789 }
790 
791 void kvmppc_core_flush_memslot_hv(struct kvm *kvm,
792                                   struct kvm_memory_slot *memslot)
793 {
794         unsigned long *rmapp;
795         unsigned long gfn;
796         unsigned long n;
797 
798         rmapp = memslot->arch.rmap;
799         gfn = memslot->base_gfn;
800         for (n = memslot->npages; n; --n) {
801                 /*
802                  * Testing the present bit without locking is OK because
803                  * the memslot has been marked invalid already, and hence
804                  * no new HPTEs referencing this page can be created,
805                  * thus the present bit can't go from 0 to 1.
806                  */
807                 if (*rmapp & KVMPPC_RMAP_PRESENT)
808                         kvm_unmap_rmapp(kvm, rmapp, gfn);
809                 ++rmapp;
810                 ++gfn;
811         }
812 }
813 
814 static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
815                          unsigned long gfn)
816 {
817         struct revmap_entry *rev = kvm->arch.revmap;
818         unsigned long head, i, j;
819         __be64 *hptep;
820         int ret = 0;
821 
822  retry:
823         lock_rmap(rmapp);
824         if (*rmapp & KVMPPC_RMAP_REFERENCED) {
825                 *rmapp &= ~KVMPPC_RMAP_REFERENCED;
826                 ret = 1;
827         }
828         if (!(*rmapp & KVMPPC_RMAP_PRESENT)) {
829                 unlock_rmap(rmapp);
830                 return ret;
831         }
832 
833         i = head = *rmapp & KVMPPC_RMAP_INDEX;
834         do {
835                 hptep = (__be64 *) (kvm->arch.hpt_virt + (i << 4));
836                 j = rev[i].forw;
837 
838                 /* If this HPTE isn't referenced, ignore it */
839                 if (!(be64_to_cpu(hptep[1]) & HPTE_R_R))
840                         continue;
841 
842                 if (!try_lock_hpte(hptep, HPTE_V_HVLOCK)) {
843                         /* unlock rmap before spinning on the HPTE lock */
844                         unlock_rmap(rmapp);
845                         while (be64_to_cpu(hptep[0]) & HPTE_V_HVLOCK)
846                                 cpu_relax();
847                         goto retry;
848                 }
849 
850                 /* Now check and modify the HPTE */
851                 if ((be64_to_cpu(hptep[0]) & HPTE_V_VALID) &&
852                     (be64_to_cpu(hptep[1]) & HPTE_R_R)) {
853                         kvmppc_clear_ref_hpte(kvm, hptep, i);
854                         if (!(rev[i].guest_rpte & HPTE_R_R)) {
855                                 rev[i].guest_rpte |= HPTE_R_R;
856                                 note_hpte_modification(kvm, &rev[i]);
857                         }
858                         ret = 1;
859                 }
860                 hptep[0] &= ~cpu_to_be64(HPTE_V_HVLOCK);
861         } while ((i = j) != head);
862 
863         unlock_rmap(rmapp);
864         return ret;
865 }
866 
867 int kvm_age_hva_hv(struct kvm *kvm, unsigned long start, unsigned long end)
868 {
869         return kvm_handle_hva_range(kvm, start, end, kvm_age_rmapp);
870 }
871 
872 static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
873                               unsigned long gfn)
874 {
875         struct revmap_entry *rev = kvm->arch.revmap;
876         unsigned long head, i, j;
877         unsigned long *hp;
878         int ret = 1;
879 
880         if (*rmapp & KVMPPC_RMAP_REFERENCED)
881                 return 1;
882 
883         lock_rmap(rmapp);
884         if (*rmapp & KVMPPC_RMAP_REFERENCED)
885                 goto out;
886 
887         if (*rmapp & KVMPPC_RMAP_PRESENT) {
888                 i = head = *rmapp & KVMPPC_RMAP_INDEX;
889                 do {
890                         hp = (unsigned long *)(kvm->arch.hpt_virt + (i << 4));
891                         j = rev[i].forw;
892                         if (be64_to_cpu(hp[1]) & HPTE_R_R)
893                                 goto out;
894                 } while ((i = j) != head);
895         }
896         ret = 0;
897 
898  out:
899         unlock_rmap(rmapp);
900         return ret;
901 }
902 
903 int kvm_test_age_hva_hv(struct kvm *kvm, unsigned long hva)
904 {
905         return kvm_handle_hva(kvm, hva, kvm_test_age_rmapp);
906 }
907 
908 void kvm_set_spte_hva_hv(struct kvm *kvm, unsigned long hva, pte_t pte)
909 {
910         kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);
911 }
912 
913 static int vcpus_running(struct kvm *kvm)
914 {
915         return atomic_read(&kvm->arch.vcpus_running) != 0;
916 }
917 
918 /*
919  * Returns the number of system pages that are dirty.
920  * This can be more than 1 if we find a huge-page HPTE.
921  */
922 static int kvm_test_clear_dirty_npages(struct kvm *kvm, unsigned long *rmapp)
923 {
924         struct revmap_entry *rev = kvm->arch.revmap;
925         unsigned long head, i, j;
926         unsigned long n;
927         unsigned long v, r;
928         __be64 *hptep;
929         int npages_dirty = 0;
930 
931  retry:
932         lock_rmap(rmapp);
933         if (*rmapp & KVMPPC_RMAP_CHANGED) {
934                 *rmapp &= ~KVMPPC_RMAP_CHANGED;
935                 npages_dirty = 1;
936         }
937         if (!(*rmapp & KVMPPC_RMAP_PRESENT)) {
938                 unlock_rmap(rmapp);
939                 return npages_dirty;
940         }
941 
942         i = head = *rmapp & KVMPPC_RMAP_INDEX;
943         do {
944                 unsigned long hptep1;
945                 hptep = (__be64 *) (kvm->arch.hpt_virt + (i << 4));
946                 j = rev[i].forw;
947 
948                 /*
949                  * Checking the C (changed) bit here is racy since there
950                  * is no guarantee about when the hardware writes it back.
951                  * If the HPTE is not writable then it is stable since the
952                  * page can't be written to, and we would have done a tlbie
953                  * (which forces the hardware to complete any writeback)
954                  * when making the HPTE read-only.
955                  * If vcpus are running then this call is racy anyway
956                  * since the page could get dirtied subsequently, so we
957                  * expect there to be a further call which would pick up
958                  * any delayed C bit writeback.
959                  * Otherwise we need to do the tlbie even if C==0 in
960                  * order to pick up any delayed writeback of C.
961                  */
962                 hptep1 = be64_to_cpu(hptep[1]);
963                 if (!(hptep1 & HPTE_R_C) &&
964                     (!hpte_is_writable(hptep1) || vcpus_running(kvm)))
965                         continue;
966 
967                 if (!try_lock_hpte(hptep, HPTE_V_HVLOCK)) {
968                         /* unlock rmap before spinning on the HPTE lock */
969                         unlock_rmap(rmapp);
970                         while (hptep[0] & cpu_to_be64(HPTE_V_HVLOCK))
971                                 cpu_relax();
972                         goto retry;
973                 }
974 
975                 /* Now check and modify the HPTE */
976                 if (!(hptep[0] & cpu_to_be64(HPTE_V_VALID))) {
977                         /* unlock and continue */
978                         hptep[0] &= ~cpu_to_be64(HPTE_V_HVLOCK);
979                         continue;
980                 }
981 
982                 /* need to make it temporarily absent so C is stable */
983                 hptep[0] |= cpu_to_be64(HPTE_V_ABSENT);
984                 kvmppc_invalidate_hpte(kvm, hptep, i);
985                 v = be64_to_cpu(hptep[0]);
986                 r = be64_to_cpu(hptep[1]);
987                 if (r & HPTE_R_C) {
988                         hptep[1] = cpu_to_be64(r & ~HPTE_R_C);
989                         if (!(rev[i].guest_rpte & HPTE_R_C)) {
990                                 rev[i].guest_rpte |= HPTE_R_C;
991                                 note_hpte_modification(kvm, &rev[i]);
992                         }
993                         n = hpte_page_size(v, r);
994                         n = (n + PAGE_SIZE - 1) >> PAGE_SHIFT;
995                         if (n > npages_dirty)
996                                 npages_dirty = n;
997                         eieio();
998                 }
999                 v &= ~(HPTE_V_ABSENT | HPTE_V_HVLOCK);
1000                 v |= HPTE_V_VALID;
1001                 hptep[0] = cpu_to_be64(v);
1002         } while ((i = j) != head);
1003 
1004         unlock_rmap(rmapp);
1005         return npages_dirty;
1006 }
1007 
1008 static void harvest_vpa_dirty(struct kvmppc_vpa *vpa,
1009                               struct kvm_memory_slot *memslot,
1010                               unsigned long *map)
1011 {
1012         unsigned long gfn;
1013 
1014         if (!vpa->dirty || !vpa->pinned_addr)
1015                 return;
1016         gfn = vpa->gpa >> PAGE_SHIFT;
1017         if (gfn < memslot->base_gfn ||
1018             gfn >= memslot->base_gfn + memslot->npages)
1019                 return;
1020 
1021         vpa->dirty = false;
1022         if (map)
1023                 __set_bit_le(gfn - memslot->base_gfn, map);
1024 }
1025 
1026 long kvmppc_hv_get_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot,
1027                              unsigned long *map)
1028 {
1029         unsigned long i, j;
1030         unsigned long *rmapp;
1031         struct kvm_vcpu *vcpu;
1032 
1033         preempt_disable();
1034         rmapp = memslot->arch.rmap;
1035         for (i = 0; i < memslot->npages; ++i) {
1036                 int npages = kvm_test_clear_dirty_npages(kvm, rmapp);
1037                 /*
1038                  * Note that if npages > 0 then i must be a multiple of npages,
1039                  * since we always put huge-page HPTEs in the rmap chain
1040                  * corresponding to their page base address.
1041                  */
1042                 if (npages && map)
1043                         for (j = i; npages; ++j, --npages)
1044                                 __set_bit_le(j, map);
1045                 ++rmapp;
1046         }
1047 
1048         /* Harvest dirty bits from VPA and DTL updates */
1049         /* Note: we never modify the SLB shadow buffer areas */
1050         kvm_for_each_vcpu(i, vcpu, kvm) {
1051                 spin_lock(&vcpu->arch.vpa_update_lock);
1052                 harvest_vpa_dirty(&vcpu->arch.vpa, memslot, map);
1053                 harvest_vpa_dirty(&vcpu->arch.dtl, memslot, map);
1054                 spin_unlock(&vcpu->arch.vpa_update_lock);
1055         }
1056         preempt_enable();
1057         return 0;
1058 }
1059 
1060 void *kvmppc_pin_guest_page(struct kvm *kvm, unsigned long gpa,
1061                             unsigned long *nb_ret)
1062 {
1063         struct kvm_memory_slot *memslot;
1064         unsigned long gfn = gpa >> PAGE_SHIFT;
1065         struct page *page, *pages[1];
1066         int npages;
1067         unsigned long hva, offset;
1068         int srcu_idx;
1069 
1070         srcu_idx = srcu_read_lock(&kvm->srcu);
1071         memslot = gfn_to_memslot(kvm, gfn);
1072         if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID))
1073                 goto err;
1074         hva = gfn_to_hva_memslot(memslot, gfn);
1075         npages = get_user_pages_fast(hva, 1, 1, pages);
1076         if (npages < 1)
1077                 goto err;
1078         page = pages[0];
1079         srcu_read_unlock(&kvm->srcu, srcu_idx);
1080 
1081         offset = gpa & (PAGE_SIZE - 1);
1082         if (nb_ret)
1083                 *nb_ret = PAGE_SIZE - offset;
1084         return page_address(page) + offset;
1085 
1086  err:
1087         srcu_read_unlock(&kvm->srcu, srcu_idx);
1088         return NULL;
1089 }
1090 
1091 void kvmppc_unpin_guest_page(struct kvm *kvm, void *va, unsigned long gpa,
1092                              bool dirty)
1093 {
1094         struct page *page = virt_to_page(va);
1095         struct kvm_memory_slot *memslot;
1096         unsigned long gfn;
1097         unsigned long *rmap;
1098         int srcu_idx;
1099 
1100         put_page(page);
1101 
1102         if (!dirty)
1103                 return;
1104 
1105         /* We need to mark this page dirty in the rmap chain */
1106         gfn = gpa >> PAGE_SHIFT;
1107         srcu_idx = srcu_read_lock(&kvm->srcu);
1108         memslot = gfn_to_memslot(kvm, gfn);
1109         if (memslot) {
1110                 rmap = &memslot->arch.rmap[gfn - memslot->base_gfn];
1111                 lock_rmap(rmap);
1112                 *rmap |= KVMPPC_RMAP_CHANGED;
1113                 unlock_rmap(rmap);
1114         }
1115         srcu_read_unlock(&kvm->srcu, srcu_idx);
1116 }
1117 
1118 /*
1119  * Functions for reading and writing the hash table via reads and
1120  * writes on a file descriptor.
1121  *
1122  * Reads return the guest view of the hash table, which has to be
1123  * pieced together from the real hash table and the guest_rpte
1124  * values in the revmap array.
1125  *
1126  * On writes, each HPTE written is considered in turn, and if it
1127  * is valid, it is written to the HPT as if an H_ENTER with the
1128  * exact flag set was done.  When the invalid count is non-zero
1129  * in the header written to the stream, the kernel will make
1130  * sure that that many HPTEs are invalid, and invalidate them
1131  * if not.
1132  */
1133 
1134 struct kvm_htab_ctx {
1135         unsigned long   index;
1136         unsigned long   flags;
1137         struct kvm      *kvm;
1138         int             first_pass;
1139 };
1140 
1141 #define HPTE_SIZE       (2 * sizeof(unsigned long))
1142 
1143 /*
1144  * Returns 1 if this HPT entry has been modified or has pending
1145  * R/C bit changes.
1146  */
1147 static int hpte_dirty(struct revmap_entry *revp, __be64 *hptp)
1148 {
1149         unsigned long rcbits_unset;
1150 
1151         if (revp->guest_rpte & HPTE_GR_MODIFIED)
1152                 return 1;
1153 
1154         /* Also need to consider changes in reference and changed bits */
1155         rcbits_unset = ~revp->guest_rpte & (HPTE_R_R | HPTE_R_C);
1156         if ((be64_to_cpu(hptp[0]) & HPTE_V_VALID) &&
1157             (be64_to_cpu(hptp[1]) & rcbits_unset))
1158                 return 1;
1159 
1160         return 0;
1161 }
1162 
1163 static long record_hpte(unsigned long flags, __be64 *hptp,
1164                         unsigned long *hpte, struct revmap_entry *revp,
1165                         int want_valid, int first_pass)
1166 {
1167         unsigned long v, r;
1168         unsigned long rcbits_unset;
1169         int ok = 1;
1170         int valid, dirty;
1171 
1172         /* Unmodified entries are uninteresting except on the first pass */
1173         dirty = hpte_dirty(revp, hptp);
1174         if (!first_pass && !dirty)
1175                 return 0;
1176 
1177         valid = 0;
1178         if (be64_to_cpu(hptp[0]) & (HPTE_V_VALID | HPTE_V_ABSENT)) {
1179                 valid = 1;
1180                 if ((flags & KVM_GET_HTAB_BOLTED_ONLY) &&
1181                     !(be64_to_cpu(hptp[0]) & HPTE_V_BOLTED))
1182                         valid = 0;
1183         }
1184         if (valid != want_valid)
1185                 return 0;
1186 
1187         v = r = 0;
1188         if (valid || dirty) {
1189                 /* lock the HPTE so it's stable and read it */
1190                 preempt_disable();
1191                 while (!try_lock_hpte(hptp, HPTE_V_HVLOCK))
1192                         cpu_relax();
1193                 v = be64_to_cpu(hptp[0]);
1194 
1195                 /* re-evaluate valid and dirty from synchronized HPTE value */
1196                 valid = !!(v & HPTE_V_VALID);
1197                 dirty = !!(revp->guest_rpte & HPTE_GR_MODIFIED);
1198 
1199                 /* Harvest R and C into guest view if necessary */
1200                 rcbits_unset = ~revp->guest_rpte & (HPTE_R_R | HPTE_R_C);
1201                 if (valid && (rcbits_unset & be64_to_cpu(hptp[1]))) {
1202                         revp->guest_rpte |= (be64_to_cpu(hptp[1]) &
1203                                 (HPTE_R_R | HPTE_R_C)) | HPTE_GR_MODIFIED;
1204                         dirty = 1;
1205                 }
1206 
1207                 if (v & HPTE_V_ABSENT) {
1208                         v &= ~HPTE_V_ABSENT;
1209                         v |= HPTE_V_VALID;
1210                         valid = 1;
1211                 }
1212                 if ((flags & KVM_GET_HTAB_BOLTED_ONLY) && !(v & HPTE_V_BOLTED))
1213                         valid = 0;
1214 
1215                 r = revp->guest_rpte;
1216                 /* only clear modified if this is the right sort of entry */
1217                 if (valid == want_valid && dirty) {
1218                         r &= ~HPTE_GR_MODIFIED;
1219                         revp->guest_rpte = r;
1220                 }
1221                 asm volatile(PPC_RELEASE_BARRIER "" : : : "memory");
1222                 hptp[0] &= ~cpu_to_be64(HPTE_V_HVLOCK);
1223                 preempt_enable();
1224                 if (!(valid == want_valid && (first_pass || dirty)))
1225                         ok = 0;
1226         }
1227         hpte[0] = cpu_to_be64(v);
1228         hpte[1] = cpu_to_be64(r);
1229         return ok;
1230 }
1231 
1232 static ssize_t kvm_htab_read(struct file *file, char __user *buf,
1233                              size_t count, loff_t *ppos)
1234 {
1235         struct kvm_htab_ctx *ctx = file->private_data;
1236         struct kvm *kvm = ctx->kvm;
1237         struct kvm_get_htab_header hdr;
1238         __be64 *hptp;
1239         struct revmap_entry *revp;
1240         unsigned long i, nb, nw;
1241         unsigned long __user *lbuf;
1242         struct kvm_get_htab_header __user *hptr;
1243         unsigned long flags;
1244         int first_pass;
1245         unsigned long hpte[2];
1246 
1247         if (!access_ok(VERIFY_WRITE, buf, count))
1248                 return -EFAULT;
1249 
1250         first_pass = ctx->first_pass;
1251         flags = ctx->flags;
1252 
1253         i = ctx->index;
1254         hptp = (__be64 *)(kvm->arch.hpt_virt + (i * HPTE_SIZE));
1255         revp = kvm->arch.revmap + i;
1256         lbuf = (unsigned long __user *)buf;
1257 
1258         nb = 0;
1259         while (nb + sizeof(hdr) + HPTE_SIZE < count) {
1260                 /* Initialize header */
1261                 hptr = (struct kvm_get_htab_header __user *)buf;
1262                 hdr.n_valid = 0;
1263                 hdr.n_invalid = 0;
1264                 nw = nb;
1265                 nb += sizeof(hdr);
1266                 lbuf = (unsigned long __user *)(buf + sizeof(hdr));
1267 
1268                 /* Skip uninteresting entries, i.e. clean on not-first pass */
1269                 if (!first_pass) {
1270                         while (i < kvm->arch.hpt_npte &&
1271                                !hpte_dirty(revp, hptp)) {
1272                                 ++i;
1273                                 hptp += 2;
1274                                 ++revp;
1275                         }
1276                 }
1277                 hdr.index = i;
1278 
1279                 /* Grab a series of valid entries */
1280                 while (i < kvm->arch.hpt_npte &&
1281                        hdr.n_valid < 0xffff &&
1282                        nb + HPTE_SIZE < count &&
1283                        record_hpte(flags, hptp, hpte, revp, 1, first_pass)) {
1284                         /* valid entry, write it out */
1285                         ++hdr.n_valid;
1286                         if (__put_user(hpte[0], lbuf) ||
1287                             __put_user(hpte[1], lbuf + 1))
1288                                 return -EFAULT;
1289                         nb += HPTE_SIZE;
1290                         lbuf += 2;
1291                         ++i;
1292                         hptp += 2;
1293                         ++revp;
1294                 }
1295                 /* Now skip invalid entries while we can */
1296                 while (i < kvm->arch.hpt_npte &&
1297                        hdr.n_invalid < 0xffff &&
1298                        record_hpte(flags, hptp, hpte, revp, 0, first_pass)) {
1299                         /* found an invalid entry */
1300                         ++hdr.n_invalid;
1301                         ++i;
1302                         hptp += 2;
1303                         ++revp;
1304                 }
1305 
1306                 if (hdr.n_valid || hdr.n_invalid) {
1307                         /* write back the header */
1308                         if (__copy_to_user(hptr, &hdr, sizeof(hdr)))
1309                                 return -EFAULT;
1310                         nw = nb;
1311                         buf = (char __user *)lbuf;
1312                 } else {
1313                         nb = nw;
1314                 }
1315 
1316                 /* Check if we've wrapped around the hash table */
1317                 if (i >= kvm->arch.hpt_npte) {
1318                         i = 0;
1319                         ctx->first_pass = 0;
1320                         break;
1321                 }
1322         }
1323 
1324         ctx->index = i;
1325 
1326         return nb;
1327 }
1328 
1329 static ssize_t kvm_htab_write(struct file *file, const char __user *buf,
1330                               size_t count, loff_t *ppos)
1331 {
1332         struct kvm_htab_ctx *ctx = file->private_data;
1333         struct kvm *kvm = ctx->kvm;
1334         struct kvm_get_htab_header hdr;
1335         unsigned long i, j;
1336         unsigned long v, r;
1337         unsigned long __user *lbuf;
1338         __be64 *hptp;
1339         unsigned long tmp[2];
1340         ssize_t nb;
1341         long int err, ret;
1342         int rma_setup;
1343 
1344         if (!access_ok(VERIFY_READ, buf, count))
1345                 return -EFAULT;
1346 
1347         /* lock out vcpus from running while we're doing this */
1348         mutex_lock(&kvm->lock);
1349         rma_setup = kvm->arch.rma_setup_done;
1350         if (rma_setup) {
1351                 kvm->arch.rma_setup_done = 0;   /* temporarily */
1352                 /* order rma_setup_done vs. vcpus_running */
1353                 smp_mb();
1354                 if (atomic_read(&kvm->arch.vcpus_running)) {
1355                         kvm->arch.rma_setup_done = 1;
1356                         mutex_unlock(&kvm->lock);
1357                         return -EBUSY;
1358                 }
1359         }
1360 
1361         err = 0;
1362         for (nb = 0; nb + sizeof(hdr) <= count; ) {
1363                 err = -EFAULT;
1364                 if (__copy_from_user(&hdr, buf, sizeof(hdr)))
1365                         break;
1366 
1367                 err = 0;
1368                 if (nb + hdr.n_valid * HPTE_SIZE > count)
1369                         break;
1370 
1371                 nb += sizeof(hdr);
1372                 buf += sizeof(hdr);
1373 
1374                 err = -EINVAL;
1375                 i = hdr.index;
1376                 if (i >= kvm->arch.hpt_npte ||
1377                     i + hdr.n_valid + hdr.n_invalid > kvm->arch.hpt_npte)
1378                         break;
1379 
1380                 hptp = (__be64 *)(kvm->arch.hpt_virt + (i * HPTE_SIZE));
1381                 lbuf = (unsigned long __user *)buf;
1382                 for (j = 0; j < hdr.n_valid; ++j) {
1383                         __be64 hpte_v;
1384                         __be64 hpte_r;
1385 
1386                         err = -EFAULT;
1387                         if (__get_user(hpte_v, lbuf) ||
1388                             __get_user(hpte_r, lbuf + 1))
1389                                 goto out;
1390                         v = be64_to_cpu(hpte_v);
1391                         r = be64_to_cpu(hpte_r);
1392                         err = -EINVAL;
1393                         if (!(v & HPTE_V_VALID))
1394                                 goto out;
1395                         lbuf += 2;
1396                         nb += HPTE_SIZE;
1397 
1398                         if (be64_to_cpu(hptp[0]) & (HPTE_V_VALID | HPTE_V_ABSENT))
1399                                 kvmppc_do_h_remove(kvm, 0, i, 0, tmp);
1400                         err = -EIO;
1401                         ret = kvmppc_virtmode_do_h_enter(kvm, H_EXACT, i, v, r,
1402                                                          tmp);
1403                         if (ret != H_SUCCESS) {
1404                                 pr_err("kvm_htab_write ret %ld i=%ld v=%lx "
1405                                        "r=%lx\n", ret, i, v, r);
1406                                 goto out;
1407                         }
1408                         if (!rma_setup && is_vrma_hpte(v)) {
1409                                 unsigned long psize = hpte_base_page_size(v, r);
1410                                 unsigned long senc = slb_pgsize_encoding(psize);
1411                                 unsigned long lpcr;
1412 
1413                                 kvm->arch.vrma_slb_v = senc | SLB_VSID_B_1T |
1414                                         (VRMA_VSID << SLB_VSID_SHIFT_1T);
1415                                 lpcr = senc << (LPCR_VRMASD_SH - 4);
1416                                 kvmppc_update_lpcr(kvm, lpcr, LPCR_VRMASD);
1417                                 rma_setup = 1;
1418                         }
1419                         ++i;
1420                         hptp += 2;
1421                 }
1422 
1423                 for (j = 0; j < hdr.n_invalid; ++j) {
1424                         if (be64_to_cpu(hptp[0]) & (HPTE_V_VALID | HPTE_V_ABSENT))
1425                                 kvmppc_do_h_remove(kvm, 0, i, 0, tmp);
1426                         ++i;
1427                         hptp += 2;
1428                 }
1429                 err = 0;
1430         }
1431 
1432  out:
1433         /* Order HPTE updates vs. rma_setup_done */
1434         smp_wmb();
1435         kvm->arch.rma_setup_done = rma_setup;
1436         mutex_unlock(&kvm->lock);
1437 
1438         if (err)
1439                 return err;
1440         return nb;
1441 }
1442 
1443 static int kvm_htab_release(struct inode *inode, struct file *filp)
1444 {
1445         struct kvm_htab_ctx *ctx = filp->private_data;
1446 
1447         filp->private_data = NULL;
1448         if (!(ctx->flags & KVM_GET_HTAB_WRITE))
1449                 atomic_dec(&ctx->kvm->arch.hpte_mod_interest);
1450         kvm_put_kvm(ctx->kvm);
1451         kfree(ctx);
1452         return 0;
1453 }
1454 
1455 static const struct file_operations kvm_htab_fops = {
1456         .read           = kvm_htab_read,
1457         .write          = kvm_htab_write,
1458         .llseek         = default_llseek,
1459         .release        = kvm_htab_release,
1460 };
1461 
1462 int kvm_vm_ioctl_get_htab_fd(struct kvm *kvm, struct kvm_get_htab_fd *ghf)
1463 {
1464         int ret;
1465         struct kvm_htab_ctx *ctx;
1466         int rwflag;
1467 
1468         /* reject flags we don't recognize */
1469         if (ghf->flags & ~(KVM_GET_HTAB_BOLTED_ONLY | KVM_GET_HTAB_WRITE))
1470                 return -EINVAL;
1471         ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
1472         if (!ctx)
1473                 return -ENOMEM;
1474         kvm_get_kvm(kvm);
1475         ctx->kvm = kvm;
1476         ctx->index = ghf->start_index;
1477         ctx->flags = ghf->flags;
1478         ctx->first_pass = 1;
1479 
1480         rwflag = (ghf->flags & KVM_GET_HTAB_WRITE) ? O_WRONLY : O_RDONLY;
1481         ret = anon_inode_getfd("kvm-htab", &kvm_htab_fops, ctx, rwflag | O_CLOEXEC);
1482         if (ret < 0) {
1483                 kvm_put_kvm(kvm);
1484                 return ret;
1485         }
1486 
1487         if (rwflag == O_RDONLY) {
1488                 mutex_lock(&kvm->slots_lock);
1489                 atomic_inc(&kvm->arch.hpte_mod_interest);
1490                 /* make sure kvmppc_do_h_enter etc. see the increment */
1491                 synchronize_srcu_expedited(&kvm->srcu);
1492                 mutex_unlock(&kvm->slots_lock);
1493         }
1494 
1495         return ret;
1496 }
1497 
1498 void kvmppc_mmu_book3s_hv_init(struct kvm_vcpu *vcpu)
1499 {
1500         struct kvmppc_mmu *mmu = &vcpu->arch.mmu;
1501 
1502         vcpu->arch.slb_nr = 32;         /* POWER7/POWER8 */
1503 
1504         mmu->xlate = kvmppc_mmu_book3s_64_hv_xlate;
1505         mmu->reset_msr = kvmppc_mmu_book3s_64_hv_reset_msr;
1506 
1507         vcpu->arch.hflags |= BOOK3S_HFLAG_SLB;
1508 }
1509 

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