xref: /openbmc/linux/arch/powerpc/kvm/book3s_64_mmu_radix.c (revision b240b419db5d624ce7a5a397d6f62a1a686009ec)
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  * Copyright 2016 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
7  */
8 
9 #include <linux/types.h>
10 #include <linux/string.h>
11 #include <linux/kvm.h>
12 #include <linux/kvm_host.h>
13 
14 #include <asm/kvm_ppc.h>
15 #include <asm/kvm_book3s.h>
16 #include <asm/page.h>
17 #include <asm/mmu.h>
18 #include <asm/pgtable.h>
19 #include <asm/pgalloc.h>
20 #include <asm/pte-walk.h>
21 
22 /*
23  * Supported radix tree geometry.
24  * Like p9, we support either 5 or 9 bits at the first (lowest) level,
25  * for a page size of 64k or 4k.
26  */
27 static int p9_supported_radix_bits[4] = { 5, 9, 9, 13 };
28 
29 int kvmppc_mmu_radix_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
30 			   struct kvmppc_pte *gpte, bool data, bool iswrite)
31 {
32 	struct kvm *kvm = vcpu->kvm;
33 	u32 pid;
34 	int ret, level, ps;
35 	__be64 prte, rpte;
36 	unsigned long ptbl;
37 	unsigned long root, pte, index;
38 	unsigned long rts, bits, offset;
39 	unsigned long gpa;
40 	unsigned long proc_tbl_size;
41 
42 	/* Work out effective PID */
43 	switch (eaddr >> 62) {
44 	case 0:
45 		pid = vcpu->arch.pid;
46 		break;
47 	case 3:
48 		pid = 0;
49 		break;
50 	default:
51 		return -EINVAL;
52 	}
53 	proc_tbl_size = 1 << ((kvm->arch.process_table & PRTS_MASK) + 12);
54 	if (pid * 16 >= proc_tbl_size)
55 		return -EINVAL;
56 
57 	/* Read partition table to find root of tree for effective PID */
58 	ptbl = (kvm->arch.process_table & PRTB_MASK) + (pid * 16);
59 	ret = kvm_read_guest(kvm, ptbl, &prte, sizeof(prte));
60 	if (ret)
61 		return ret;
62 
63 	root = be64_to_cpu(prte);
64 	rts = ((root & RTS1_MASK) >> (RTS1_SHIFT - 3)) |
65 		((root & RTS2_MASK) >> RTS2_SHIFT);
66 	bits = root & RPDS_MASK;
67 	root = root & RPDB_MASK;
68 
69 	/* P9 DD1 interprets RTS (radix tree size) differently */
70 	offset = rts + 31;
71 	if (cpu_has_feature(CPU_FTR_POWER9_DD1))
72 		offset -= 3;
73 
74 	/* current implementations only support 52-bit space */
75 	if (offset != 52)
76 		return -EINVAL;
77 
78 	for (level = 3; level >= 0; --level) {
79 		if (level && bits != p9_supported_radix_bits[level])
80 			return -EINVAL;
81 		if (level == 0 && !(bits == 5 || bits == 9))
82 			return -EINVAL;
83 		offset -= bits;
84 		index = (eaddr >> offset) & ((1UL << bits) - 1);
85 		/* check that low bits of page table base are zero */
86 		if (root & ((1UL << (bits + 3)) - 1))
87 			return -EINVAL;
88 		ret = kvm_read_guest(kvm, root + index * 8,
89 				     &rpte, sizeof(rpte));
90 		if (ret)
91 			return ret;
92 		pte = __be64_to_cpu(rpte);
93 		if (!(pte & _PAGE_PRESENT))
94 			return -ENOENT;
95 		if (pte & _PAGE_PTE)
96 			break;
97 		bits = pte & 0x1f;
98 		root = pte & 0x0fffffffffffff00ul;
99 	}
100 	/* need a leaf at lowest level; 512GB pages not supported */
101 	if (level < 0 || level == 3)
102 		return -EINVAL;
103 
104 	/* offset is now log base 2 of the page size */
105 	gpa = pte & 0x01fffffffffff000ul;
106 	if (gpa & ((1ul << offset) - 1))
107 		return -EINVAL;
108 	gpa += eaddr & ((1ul << offset) - 1);
109 	for (ps = MMU_PAGE_4K; ps < MMU_PAGE_COUNT; ++ps)
110 		if (offset == mmu_psize_defs[ps].shift)
111 			break;
112 	gpte->page_size = ps;
113 
114 	gpte->eaddr = eaddr;
115 	gpte->raddr = gpa;
116 
117 	/* Work out permissions */
118 	gpte->may_read = !!(pte & _PAGE_READ);
119 	gpte->may_write = !!(pte & _PAGE_WRITE);
120 	gpte->may_execute = !!(pte & _PAGE_EXEC);
121 	if (kvmppc_get_msr(vcpu) & MSR_PR) {
122 		if (pte & _PAGE_PRIVILEGED) {
123 			gpte->may_read = 0;
124 			gpte->may_write = 0;
125 			gpte->may_execute = 0;
126 		}
127 	} else {
128 		if (!(pte & _PAGE_PRIVILEGED)) {
129 			/* Check AMR/IAMR to see if strict mode is in force */
130 			if (vcpu->arch.amr & (1ul << 62))
131 				gpte->may_read = 0;
132 			if (vcpu->arch.amr & (1ul << 63))
133 				gpte->may_write = 0;
134 			if (vcpu->arch.iamr & (1ul << 62))
135 				gpte->may_execute = 0;
136 		}
137 	}
138 
139 	return 0;
140 }
141 
142 #ifdef CONFIG_PPC_64K_PAGES
143 #define MMU_BASE_PSIZE	MMU_PAGE_64K
144 #else
145 #define MMU_BASE_PSIZE	MMU_PAGE_4K
146 #endif
147 
148 static void kvmppc_radix_tlbie_page(struct kvm *kvm, unsigned long addr,
149 				    unsigned int pshift)
150 {
151 	int psize = MMU_BASE_PSIZE;
152 
153 	if (pshift >= PMD_SHIFT)
154 		psize = MMU_PAGE_2M;
155 	addr &= ~0xfffUL;
156 	addr |= mmu_psize_defs[psize].ap << 5;
157 	asm volatile("ptesync": : :"memory");
158 	asm volatile(PPC_TLBIE_5(%0, %1, 0, 0, 1)
159 		     : : "r" (addr), "r" (kvm->arch.lpid) : "memory");
160 	if (cpu_has_feature(CPU_FTR_P9_TLBIE_BUG))
161 		asm volatile(PPC_TLBIE_5(%0, %1, 0, 0, 1)
162 			     : : "r" (addr), "r" (kvm->arch.lpid) : "memory");
163 	asm volatile("ptesync": : :"memory");
164 }
165 
166 unsigned long kvmppc_radix_update_pte(struct kvm *kvm, pte_t *ptep,
167 				      unsigned long clr, unsigned long set,
168 				      unsigned long addr, unsigned int shift)
169 {
170 	unsigned long old = 0;
171 
172 	if (!(clr & _PAGE_PRESENT) && cpu_has_feature(CPU_FTR_POWER9_DD1) &&
173 	    pte_present(*ptep)) {
174 		/* have to invalidate it first */
175 		old = __radix_pte_update(ptep, _PAGE_PRESENT, 0);
176 		kvmppc_radix_tlbie_page(kvm, addr, shift);
177 		set |= _PAGE_PRESENT;
178 		old &= _PAGE_PRESENT;
179 	}
180 	return __radix_pte_update(ptep, clr, set) | old;
181 }
182 
183 void kvmppc_radix_set_pte_at(struct kvm *kvm, unsigned long addr,
184 			     pte_t *ptep, pte_t pte)
185 {
186 	radix__set_pte_at(kvm->mm, addr, ptep, pte, 0);
187 }
188 
189 static struct kmem_cache *kvm_pte_cache;
190 
191 static pte_t *kvmppc_pte_alloc(void)
192 {
193 	return kmem_cache_alloc(kvm_pte_cache, GFP_KERNEL);
194 }
195 
196 static void kvmppc_pte_free(pte_t *ptep)
197 {
198 	kmem_cache_free(kvm_pte_cache, ptep);
199 }
200 
201 /* Like pmd_huge() and pmd_large(), but works regardless of config options */
202 static inline int pmd_is_leaf(pmd_t pmd)
203 {
204 	return !!(pmd_val(pmd) & _PAGE_PTE);
205 }
206 
207 static int kvmppc_create_pte(struct kvm *kvm, pte_t pte, unsigned long gpa,
208 			     unsigned int level, unsigned long mmu_seq)
209 {
210 	pgd_t *pgd;
211 	pud_t *pud, *new_pud = NULL;
212 	pmd_t *pmd, *new_pmd = NULL;
213 	pte_t *ptep, *new_ptep = NULL;
214 	unsigned long old;
215 	int ret;
216 
217 	/* Traverse the guest's 2nd-level tree, allocate new levels needed */
218 	pgd = kvm->arch.pgtable + pgd_index(gpa);
219 	pud = NULL;
220 	if (pgd_present(*pgd))
221 		pud = pud_offset(pgd, gpa);
222 	else
223 		new_pud = pud_alloc_one(kvm->mm, gpa);
224 
225 	pmd = NULL;
226 	if (pud && pud_present(*pud))
227 		pmd = pmd_offset(pud, gpa);
228 	else
229 		new_pmd = pmd_alloc_one(kvm->mm, gpa);
230 
231 	if (level == 0 && !(pmd && pmd_present(*pmd) && !pmd_is_leaf(*pmd)))
232 		new_ptep = kvmppc_pte_alloc();
233 
234 	/* Check if we might have been invalidated; let the guest retry if so */
235 	spin_lock(&kvm->mmu_lock);
236 	ret = -EAGAIN;
237 	if (mmu_notifier_retry(kvm, mmu_seq))
238 		goto out_unlock;
239 
240 	/* Now traverse again under the lock and change the tree */
241 	ret = -ENOMEM;
242 	if (pgd_none(*pgd)) {
243 		if (!new_pud)
244 			goto out_unlock;
245 		pgd_populate(kvm->mm, pgd, new_pud);
246 		new_pud = NULL;
247 	}
248 	pud = pud_offset(pgd, gpa);
249 	if (pud_none(*pud)) {
250 		if (!new_pmd)
251 			goto out_unlock;
252 		pud_populate(kvm->mm, pud, new_pmd);
253 		new_pmd = NULL;
254 	}
255 	pmd = pmd_offset(pud, gpa);
256 	if (pmd_is_leaf(*pmd)) {
257 		unsigned long lgpa = gpa & PMD_MASK;
258 
259 		/*
260 		 * If we raced with another CPU which has just put
261 		 * a 2MB pte in after we saw a pte page, try again.
262 		 */
263 		if (level == 0 && !new_ptep) {
264 			ret = -EAGAIN;
265 			goto out_unlock;
266 		}
267 		/* Valid 2MB page here already, remove it */
268 		old = kvmppc_radix_update_pte(kvm, pmdp_ptep(pmd),
269 					      ~0UL, 0, lgpa, PMD_SHIFT);
270 		kvmppc_radix_tlbie_page(kvm, lgpa, PMD_SHIFT);
271 		if (old & _PAGE_DIRTY) {
272 			unsigned long gfn = lgpa >> PAGE_SHIFT;
273 			struct kvm_memory_slot *memslot;
274 			memslot = gfn_to_memslot(kvm, gfn);
275 			if (memslot && memslot->dirty_bitmap)
276 				kvmppc_update_dirty_map(memslot,
277 							gfn, PMD_SIZE);
278 		}
279 	} else if (level == 1 && !pmd_none(*pmd)) {
280 		/*
281 		 * There's a page table page here, but we wanted
282 		 * to install a large page.  Tell the caller and let
283 		 * it try installing a normal page if it wants.
284 		 */
285 		ret = -EBUSY;
286 		goto out_unlock;
287 	}
288 	if (level == 0) {
289 		if (pmd_none(*pmd)) {
290 			if (!new_ptep)
291 				goto out_unlock;
292 			pmd_populate(kvm->mm, pmd, new_ptep);
293 			new_ptep = NULL;
294 		}
295 		ptep = pte_offset_kernel(pmd, gpa);
296 		if (pte_present(*ptep)) {
297 			/* PTE was previously valid, so invalidate it */
298 			old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_PRESENT,
299 						      0, gpa, 0);
300 			kvmppc_radix_tlbie_page(kvm, gpa, 0);
301 			if (old & _PAGE_DIRTY)
302 				mark_page_dirty(kvm, gpa >> PAGE_SHIFT);
303 		}
304 		kvmppc_radix_set_pte_at(kvm, gpa, ptep, pte);
305 	} else {
306 		kvmppc_radix_set_pte_at(kvm, gpa, pmdp_ptep(pmd), pte);
307 	}
308 	ret = 0;
309 
310  out_unlock:
311 	spin_unlock(&kvm->mmu_lock);
312 	if (new_pud)
313 		pud_free(kvm->mm, new_pud);
314 	if (new_pmd)
315 		pmd_free(kvm->mm, new_pmd);
316 	if (new_ptep)
317 		kvmppc_pte_free(new_ptep);
318 	return ret;
319 }
320 
321 int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
322 				   unsigned long ea, unsigned long dsisr)
323 {
324 	struct kvm *kvm = vcpu->kvm;
325 	unsigned long mmu_seq, pte_size;
326 	unsigned long gpa, gfn, hva, pfn;
327 	struct kvm_memory_slot *memslot;
328 	struct page *page = NULL, *pages[1];
329 	long ret, npages, ok;
330 	unsigned int writing;
331 	struct vm_area_struct *vma;
332 	unsigned long flags;
333 	pte_t pte, *ptep;
334 	unsigned long pgflags;
335 	unsigned int shift, level;
336 
337 	/* Check for unusual errors */
338 	if (dsisr & DSISR_UNSUPP_MMU) {
339 		pr_err("KVM: Got unsupported MMU fault\n");
340 		return -EFAULT;
341 	}
342 	if (dsisr & DSISR_BADACCESS) {
343 		/* Reflect to the guest as DSI */
344 		pr_err("KVM: Got radix HV page fault with DSISR=%lx\n", dsisr);
345 		kvmppc_core_queue_data_storage(vcpu, ea, dsisr);
346 		return RESUME_GUEST;
347 	}
348 
349 	/* Translate the logical address and get the page */
350 	gpa = vcpu->arch.fault_gpa & ~0xfffUL;
351 	gpa &= ~0xF000000000000000ul;
352 	gfn = gpa >> PAGE_SHIFT;
353 	if (!(dsisr & DSISR_PRTABLE_FAULT))
354 		gpa |= ea & 0xfff;
355 	memslot = gfn_to_memslot(kvm, gfn);
356 
357 	/* No memslot means it's an emulated MMIO region */
358 	if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID)) {
359 		if (dsisr & (DSISR_PRTABLE_FAULT | DSISR_BADACCESS |
360 			     DSISR_SET_RC)) {
361 			/*
362 			 * Bad address in guest page table tree, or other
363 			 * unusual error - reflect it to the guest as DSI.
364 			 */
365 			kvmppc_core_queue_data_storage(vcpu, ea, dsisr);
366 			return RESUME_GUEST;
367 		}
368 		return kvmppc_hv_emulate_mmio(run, vcpu, gpa, ea,
369 					      dsisr & DSISR_ISSTORE);
370 	}
371 
372 	/* used to check for invalidations in progress */
373 	mmu_seq = kvm->mmu_notifier_seq;
374 	smp_rmb();
375 
376 	writing = (dsisr & DSISR_ISSTORE) != 0;
377 	hva = gfn_to_hva_memslot(memslot, gfn);
378 	if (dsisr & DSISR_SET_RC) {
379 		/*
380 		 * Need to set an R or C bit in the 2nd-level tables;
381 		 * if the relevant bits aren't already set in the linux
382 		 * page tables, fall through to do the gup_fast to
383 		 * set them in the linux page tables too.
384 		 */
385 		ok = 0;
386 		pgflags = _PAGE_ACCESSED;
387 		if (writing)
388 			pgflags |= _PAGE_DIRTY;
389 		local_irq_save(flags);
390 		ptep = find_current_mm_pte(current->mm->pgd, hva, NULL, NULL);
391 		if (ptep) {
392 			pte = READ_ONCE(*ptep);
393 			if (pte_present(pte) &&
394 			    (pte_val(pte) & pgflags) == pgflags)
395 				ok = 1;
396 		}
397 		local_irq_restore(flags);
398 		if (ok) {
399 			spin_lock(&kvm->mmu_lock);
400 			if (mmu_notifier_retry(vcpu->kvm, mmu_seq)) {
401 				spin_unlock(&kvm->mmu_lock);
402 				return RESUME_GUEST;
403 			}
404 			/*
405 			 * We are walking the secondary page table here. We can do this
406 			 * without disabling irq.
407 			 */
408 			ptep = __find_linux_pte(kvm->arch.pgtable,
409 						gpa, NULL, &shift);
410 			if (ptep && pte_present(*ptep)) {
411 				kvmppc_radix_update_pte(kvm, ptep, 0, pgflags,
412 							gpa, shift);
413 				spin_unlock(&kvm->mmu_lock);
414 				return RESUME_GUEST;
415 			}
416 			spin_unlock(&kvm->mmu_lock);
417 		}
418 	}
419 
420 	ret = -EFAULT;
421 	pfn = 0;
422 	pte_size = PAGE_SIZE;
423 	pgflags = _PAGE_READ | _PAGE_EXEC;
424 	level = 0;
425 	npages = get_user_pages_fast(hva, 1, writing, pages);
426 	if (npages < 1) {
427 		/* Check if it's an I/O mapping */
428 		down_read(&current->mm->mmap_sem);
429 		vma = find_vma(current->mm, hva);
430 		if (vma && vma->vm_start <= hva && hva < vma->vm_end &&
431 		    (vma->vm_flags & VM_PFNMAP)) {
432 			pfn = vma->vm_pgoff +
433 				((hva - vma->vm_start) >> PAGE_SHIFT);
434 			pgflags = pgprot_val(vma->vm_page_prot);
435 		}
436 		up_read(&current->mm->mmap_sem);
437 		if (!pfn)
438 			return -EFAULT;
439 	} else {
440 		page = pages[0];
441 		pfn = page_to_pfn(page);
442 		if (PageCompound(page)) {
443 			pte_size <<= compound_order(compound_head(page));
444 			/* See if we can insert a 2MB large-page PTE here */
445 			if (pte_size >= PMD_SIZE &&
446 			    (gpa & (PMD_SIZE - PAGE_SIZE)) ==
447 			    (hva & (PMD_SIZE - PAGE_SIZE))) {
448 				level = 1;
449 				pfn &= ~((PMD_SIZE >> PAGE_SHIFT) - 1);
450 			}
451 		}
452 		/* See if we can provide write access */
453 		if (writing) {
454 			pgflags |= _PAGE_WRITE;
455 		} else {
456 			local_irq_save(flags);
457 			ptep = find_current_mm_pte(current->mm->pgd,
458 						   hva, NULL, NULL);
459 			if (ptep && pte_write(*ptep))
460 				pgflags |= _PAGE_WRITE;
461 			local_irq_restore(flags);
462 		}
463 	}
464 
465 	/*
466 	 * Compute the PTE value that we need to insert.
467 	 */
468 	pgflags |= _PAGE_PRESENT | _PAGE_PTE | _PAGE_ACCESSED;
469 	if (pgflags & _PAGE_WRITE)
470 		pgflags |= _PAGE_DIRTY;
471 	pte = pfn_pte(pfn, __pgprot(pgflags));
472 
473 	/* Allocate space in the tree and write the PTE */
474 	ret = kvmppc_create_pte(kvm, pte, gpa, level, mmu_seq);
475 	if (ret == -EBUSY) {
476 		/*
477 		 * There's already a PMD where wanted to install a large page;
478 		 * for now, fall back to installing a small page.
479 		 */
480 		level = 0;
481 		pfn |= gfn & ((PMD_SIZE >> PAGE_SHIFT) - 1);
482 		pte = pfn_pte(pfn, __pgprot(pgflags));
483 		ret = kvmppc_create_pte(kvm, pte, gpa, level, mmu_seq);
484 	}
485 
486 	if (page) {
487 		if (!ret && (pgflags & _PAGE_WRITE))
488 			set_page_dirty_lock(page);
489 		put_page(page);
490 	}
491 
492 	if (ret == 0 || ret == -EAGAIN)
493 		ret = RESUME_GUEST;
494 	return ret;
495 }
496 
497 /* Called with kvm->lock held */
498 int kvm_unmap_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
499 		    unsigned long gfn)
500 {
501 	pte_t *ptep;
502 	unsigned long gpa = gfn << PAGE_SHIFT;
503 	unsigned int shift;
504 	unsigned long old;
505 
506 	ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
507 	if (ptep && pte_present(*ptep)) {
508 		old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_PRESENT, 0,
509 					      gpa, shift);
510 		kvmppc_radix_tlbie_page(kvm, gpa, shift);
511 		if ((old & _PAGE_DIRTY) && memslot->dirty_bitmap) {
512 			unsigned long npages = 1;
513 			if (shift)
514 				npages = 1ul << (shift - PAGE_SHIFT);
515 			kvmppc_update_dirty_map(memslot, gfn, npages);
516 		}
517 	}
518 	return 0;
519 }
520 
521 /* Called with kvm->lock held */
522 int kvm_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
523 		  unsigned long gfn)
524 {
525 	pte_t *ptep;
526 	unsigned long gpa = gfn << PAGE_SHIFT;
527 	unsigned int shift;
528 	int ref = 0;
529 
530 	ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
531 	if (ptep && pte_present(*ptep) && pte_young(*ptep)) {
532 		kvmppc_radix_update_pte(kvm, ptep, _PAGE_ACCESSED, 0,
533 					gpa, shift);
534 		/* XXX need to flush tlb here? */
535 		ref = 1;
536 	}
537 	return ref;
538 }
539 
540 /* Called with kvm->lock held */
541 int kvm_test_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
542 		       unsigned long gfn)
543 {
544 	pte_t *ptep;
545 	unsigned long gpa = gfn << PAGE_SHIFT;
546 	unsigned int shift;
547 	int ref = 0;
548 
549 	ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
550 	if (ptep && pte_present(*ptep) && pte_young(*ptep))
551 		ref = 1;
552 	return ref;
553 }
554 
555 /* Returns the number of PAGE_SIZE pages that are dirty */
556 static int kvm_radix_test_clear_dirty(struct kvm *kvm,
557 				struct kvm_memory_slot *memslot, int pagenum)
558 {
559 	unsigned long gfn = memslot->base_gfn + pagenum;
560 	unsigned long gpa = gfn << PAGE_SHIFT;
561 	pte_t *ptep;
562 	unsigned int shift;
563 	int ret = 0;
564 
565 	ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
566 	if (ptep && pte_present(*ptep) && pte_dirty(*ptep)) {
567 		ret = 1;
568 		if (shift)
569 			ret = 1 << (shift - PAGE_SHIFT);
570 		kvmppc_radix_update_pte(kvm, ptep, _PAGE_DIRTY, 0,
571 					gpa, shift);
572 		kvmppc_radix_tlbie_page(kvm, gpa, shift);
573 	}
574 	return ret;
575 }
576 
577 long kvmppc_hv_get_dirty_log_radix(struct kvm *kvm,
578 			struct kvm_memory_slot *memslot, unsigned long *map)
579 {
580 	unsigned long i, j;
581 	int npages;
582 
583 	for (i = 0; i < memslot->npages; i = j) {
584 		npages = kvm_radix_test_clear_dirty(kvm, memslot, i);
585 
586 		/*
587 		 * Note that if npages > 0 then i must be a multiple of npages,
588 		 * since huge pages are only used to back the guest at guest
589 		 * real addresses that are a multiple of their size.
590 		 * Since we have at most one PTE covering any given guest
591 		 * real address, if npages > 1 we can skip to i + npages.
592 		 */
593 		j = i + 1;
594 		if (npages) {
595 			set_dirty_bits(map, i, npages);
596 			j = i + npages;
597 		}
598 	}
599 	return 0;
600 }
601 
602 static void add_rmmu_ap_encoding(struct kvm_ppc_rmmu_info *info,
603 				 int psize, int *indexp)
604 {
605 	if (!mmu_psize_defs[psize].shift)
606 		return;
607 	info->ap_encodings[*indexp] = mmu_psize_defs[psize].shift |
608 		(mmu_psize_defs[psize].ap << 29);
609 	++(*indexp);
610 }
611 
612 int kvmhv_get_rmmu_info(struct kvm *kvm, struct kvm_ppc_rmmu_info *info)
613 {
614 	int i;
615 
616 	if (!radix_enabled())
617 		return -EINVAL;
618 	memset(info, 0, sizeof(*info));
619 
620 	/* 4k page size */
621 	info->geometries[0].page_shift = 12;
622 	info->geometries[0].level_bits[0] = 9;
623 	for (i = 1; i < 4; ++i)
624 		info->geometries[0].level_bits[i] = p9_supported_radix_bits[i];
625 	/* 64k page size */
626 	info->geometries[1].page_shift = 16;
627 	for (i = 0; i < 4; ++i)
628 		info->geometries[1].level_bits[i] = p9_supported_radix_bits[i];
629 
630 	i = 0;
631 	add_rmmu_ap_encoding(info, MMU_PAGE_4K, &i);
632 	add_rmmu_ap_encoding(info, MMU_PAGE_64K, &i);
633 	add_rmmu_ap_encoding(info, MMU_PAGE_2M, &i);
634 	add_rmmu_ap_encoding(info, MMU_PAGE_1G, &i);
635 
636 	return 0;
637 }
638 
639 int kvmppc_init_vm_radix(struct kvm *kvm)
640 {
641 	kvm->arch.pgtable = pgd_alloc(kvm->mm);
642 	if (!kvm->arch.pgtable)
643 		return -ENOMEM;
644 	return 0;
645 }
646 
647 void kvmppc_free_radix(struct kvm *kvm)
648 {
649 	unsigned long ig, iu, im;
650 	pte_t *pte;
651 	pmd_t *pmd;
652 	pud_t *pud;
653 	pgd_t *pgd;
654 
655 	if (!kvm->arch.pgtable)
656 		return;
657 	pgd = kvm->arch.pgtable;
658 	for (ig = 0; ig < PTRS_PER_PGD; ++ig, ++pgd) {
659 		if (!pgd_present(*pgd))
660 			continue;
661 		pud = pud_offset(pgd, 0);
662 		for (iu = 0; iu < PTRS_PER_PUD; ++iu, ++pud) {
663 			if (!pud_present(*pud))
664 				continue;
665 			pmd = pmd_offset(pud, 0);
666 			for (im = 0; im < PTRS_PER_PMD; ++im, ++pmd) {
667 				if (pmd_is_leaf(*pmd)) {
668 					pmd_clear(pmd);
669 					continue;
670 				}
671 				if (!pmd_present(*pmd))
672 					continue;
673 				pte = pte_offset_map(pmd, 0);
674 				memset(pte, 0, sizeof(long) << PTE_INDEX_SIZE);
675 				kvmppc_pte_free(pte);
676 				pmd_clear(pmd);
677 			}
678 			pmd_free(kvm->mm, pmd_offset(pud, 0));
679 			pud_clear(pud);
680 		}
681 		pud_free(kvm->mm, pud_offset(pgd, 0));
682 		pgd_clear(pgd);
683 	}
684 	pgd_free(kvm->mm, kvm->arch.pgtable);
685 	kvm->arch.pgtable = NULL;
686 }
687 
688 static void pte_ctor(void *addr)
689 {
690 	memset(addr, 0, PTE_TABLE_SIZE);
691 }
692 
693 int kvmppc_radix_init(void)
694 {
695 	unsigned long size = sizeof(void *) << PTE_INDEX_SIZE;
696 
697 	kvm_pte_cache = kmem_cache_create("kvm-pte", size, size, 0, pte_ctor);
698 	if (!kvm_pte_cache)
699 		return -ENOMEM;
700 	return 0;
701 }
702 
703 void kvmppc_radix_exit(void)
704 {
705 	kmem_cache_destroy(kvm_pte_cache);
706 }
707