xref: /linux/arch/powerpc/kvm/book3s_64_mmu_radix.c (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9)
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 
21 /*
22  * Supported radix tree geometry.
23  * Like p9, we support either 5 or 9 bits at the first (lowest) level,
24  * for a page size of 64k or 4k.
25  */
26 static int p9_supported_radix_bits[4] = { 5, 9, 9, 13 };
27 
28 int kvmppc_mmu_radix_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
29 			   struct kvmppc_pte *gpte, bool data, bool iswrite)
30 {
31 	struct kvm *kvm = vcpu->kvm;
32 	u32 pid;
33 	int ret, level, ps;
34 	__be64 prte, rpte;
35 	unsigned long ptbl;
36 	unsigned long root, pte, index;
37 	unsigned long rts, bits, offset;
38 	unsigned long gpa;
39 	unsigned long proc_tbl_size;
40 
41 	/* Work out effective PID */
42 	switch (eaddr >> 62) {
43 	case 0:
44 		pid = vcpu->arch.pid;
45 		break;
46 	case 3:
47 		pid = 0;
48 		break;
49 	default:
50 		return -EINVAL;
51 	}
52 	proc_tbl_size = 1 << ((kvm->arch.process_table & PRTS_MASK) + 12);
53 	if (pid * 16 >= proc_tbl_size)
54 		return -EINVAL;
55 
56 	/* Read partition table to find root of tree for effective PID */
57 	ptbl = (kvm->arch.process_table & PRTB_MASK) + (pid * 16);
58 	ret = kvm_read_guest(kvm, ptbl, &prte, sizeof(prte));
59 	if (ret)
60 		return ret;
61 
62 	root = be64_to_cpu(prte);
63 	rts = ((root & RTS1_MASK) >> (RTS1_SHIFT - 3)) |
64 		((root & RTS2_MASK) >> RTS2_SHIFT);
65 	bits = root & RPDS_MASK;
66 	root = root & RPDB_MASK;
67 
68 	/* P9 DD1 interprets RTS (radix tree size) differently */
69 	offset = rts + 31;
70 	if (cpu_has_feature(CPU_FTR_POWER9_DD1))
71 		offset -= 3;
72 
73 	/* current implementations only support 52-bit space */
74 	if (offset != 52)
75 		return -EINVAL;
76 
77 	for (level = 3; level >= 0; --level) {
78 		if (level && bits != p9_supported_radix_bits[level])
79 			return -EINVAL;
80 		if (level == 0 && !(bits == 5 || bits == 9))
81 			return -EINVAL;
82 		offset -= bits;
83 		index = (eaddr >> offset) & ((1UL << bits) - 1);
84 		/* check that low bits of page table base are zero */
85 		if (root & ((1UL << (bits + 3)) - 1))
86 			return -EINVAL;
87 		ret = kvm_read_guest(kvm, root + index * 8,
88 				     &rpte, sizeof(rpte));
89 		if (ret)
90 			return ret;
91 		pte = __be64_to_cpu(rpte);
92 		if (!(pte & _PAGE_PRESENT))
93 			return -ENOENT;
94 		if (pte & _PAGE_PTE)
95 			break;
96 		bits = pte & 0x1f;
97 		root = pte & 0x0fffffffffffff00ul;
98 	}
99 	/* need a leaf at lowest level; 512GB pages not supported */
100 	if (level < 0 || level == 3)
101 		return -EINVAL;
102 
103 	/* offset is now log base 2 of the page size */
104 	gpa = pte & 0x01fffffffffff000ul;
105 	if (gpa & ((1ul << offset) - 1))
106 		return -EINVAL;
107 	gpa += eaddr & ((1ul << offset) - 1);
108 	for (ps = MMU_PAGE_4K; ps < MMU_PAGE_COUNT; ++ps)
109 		if (offset == mmu_psize_defs[ps].shift)
110 			break;
111 	gpte->page_size = ps;
112 
113 	gpte->eaddr = eaddr;
114 	gpte->raddr = gpa;
115 
116 	/* Work out permissions */
117 	gpte->may_read = !!(pte & _PAGE_READ);
118 	gpte->may_write = !!(pte & _PAGE_WRITE);
119 	gpte->may_execute = !!(pte & _PAGE_EXEC);
120 	if (kvmppc_get_msr(vcpu) & MSR_PR) {
121 		if (pte & _PAGE_PRIVILEGED) {
122 			gpte->may_read = 0;
123 			gpte->may_write = 0;
124 			gpte->may_execute = 0;
125 		}
126 	} else {
127 		if (!(pte & _PAGE_PRIVILEGED)) {
128 			/* Check AMR/IAMR to see if strict mode is in force */
129 			if (vcpu->arch.amr & (1ul << 62))
130 				gpte->may_read = 0;
131 			if (vcpu->arch.amr & (1ul << 63))
132 				gpte->may_write = 0;
133 			if (vcpu->arch.iamr & (1ul << 62))
134 				gpte->may_execute = 0;
135 		}
136 	}
137 
138 	return 0;
139 }
140 
141 #ifdef CONFIG_PPC_64K_PAGES
142 #define MMU_BASE_PSIZE	MMU_PAGE_64K
143 #else
144 #define MMU_BASE_PSIZE	MMU_PAGE_4K
145 #endif
146 
147 static void kvmppc_radix_tlbie_page(struct kvm *kvm, unsigned long addr,
148 				    unsigned int pshift)
149 {
150 	int psize = MMU_BASE_PSIZE;
151 
152 	if (pshift >= PMD_SHIFT)
153 		psize = MMU_PAGE_2M;
154 	addr &= ~0xfffUL;
155 	addr |= mmu_psize_defs[psize].ap << 5;
156 	asm volatile("ptesync": : :"memory");
157 	asm volatile(PPC_TLBIE_5(%0, %1, 0, 0, 1)
158 		     : : "r" (addr), "r" (kvm->arch.lpid) : "memory");
159 	asm volatile("ptesync": : :"memory");
160 }
161 
162 unsigned long kvmppc_radix_update_pte(struct kvm *kvm, pte_t *ptep,
163 				      unsigned long clr, unsigned long set,
164 				      unsigned long addr, unsigned int shift)
165 {
166 	unsigned long old = 0;
167 
168 	if (!(clr & _PAGE_PRESENT) && cpu_has_feature(CPU_FTR_POWER9_DD1) &&
169 	    pte_present(*ptep)) {
170 		/* have to invalidate it first */
171 		old = __radix_pte_update(ptep, _PAGE_PRESENT, 0);
172 		kvmppc_radix_tlbie_page(kvm, addr, shift);
173 		set |= _PAGE_PRESENT;
174 		old &= _PAGE_PRESENT;
175 	}
176 	return __radix_pte_update(ptep, clr, set) | old;
177 }
178 
179 void kvmppc_radix_set_pte_at(struct kvm *kvm, unsigned long addr,
180 			     pte_t *ptep, pte_t pte)
181 {
182 	radix__set_pte_at(kvm->mm, addr, ptep, pte, 0);
183 }
184 
185 static struct kmem_cache *kvm_pte_cache;
186 
187 static pte_t *kvmppc_pte_alloc(void)
188 {
189 	return kmem_cache_alloc(kvm_pte_cache, GFP_KERNEL);
190 }
191 
192 static void kvmppc_pte_free(pte_t *ptep)
193 {
194 	kmem_cache_free(kvm_pte_cache, ptep);
195 }
196 
197 static int kvmppc_create_pte(struct kvm *kvm, pte_t pte, unsigned long gpa,
198 			     unsigned int level, unsigned long mmu_seq)
199 {
200 	pgd_t *pgd;
201 	pud_t *pud, *new_pud = NULL;
202 	pmd_t *pmd, *new_pmd = NULL;
203 	pte_t *ptep, *new_ptep = NULL;
204 	unsigned long old;
205 	int ret;
206 
207 	/* Traverse the guest's 2nd-level tree, allocate new levels needed */
208 	pgd = kvm->arch.pgtable + pgd_index(gpa);
209 	pud = NULL;
210 	if (pgd_present(*pgd))
211 		pud = pud_offset(pgd, gpa);
212 	else
213 		new_pud = pud_alloc_one(kvm->mm, gpa);
214 
215 	pmd = NULL;
216 	if (pud && pud_present(*pud))
217 		pmd = pmd_offset(pud, gpa);
218 	else
219 		new_pmd = pmd_alloc_one(kvm->mm, gpa);
220 
221 	if (level == 0 && !(pmd && pmd_present(*pmd)))
222 		new_ptep = kvmppc_pte_alloc();
223 
224 	/* Check if we might have been invalidated; let the guest retry if so */
225 	spin_lock(&kvm->mmu_lock);
226 	ret = -EAGAIN;
227 	if (mmu_notifier_retry(kvm, mmu_seq))
228 		goto out_unlock;
229 
230 	/* Now traverse again under the lock and change the tree */
231 	ret = -ENOMEM;
232 	if (pgd_none(*pgd)) {
233 		if (!new_pud)
234 			goto out_unlock;
235 		pgd_populate(kvm->mm, pgd, new_pud);
236 		new_pud = NULL;
237 	}
238 	pud = pud_offset(pgd, gpa);
239 	if (pud_none(*pud)) {
240 		if (!new_pmd)
241 			goto out_unlock;
242 		pud_populate(kvm->mm, pud, new_pmd);
243 		new_pmd = NULL;
244 	}
245 	pmd = pmd_offset(pud, gpa);
246 	if (pmd_large(*pmd)) {
247 		/* Someone else has instantiated a large page here; retry */
248 		ret = -EAGAIN;
249 		goto out_unlock;
250 	}
251 	if (level == 1 && !pmd_none(*pmd)) {
252 		/*
253 		 * There's a page table page here, but we wanted
254 		 * to install a large page.  Tell the caller and let
255 		 * it try installing a normal page if it wants.
256 		 */
257 		ret = -EBUSY;
258 		goto out_unlock;
259 	}
260 	if (level == 0) {
261 		if (pmd_none(*pmd)) {
262 			if (!new_ptep)
263 				goto out_unlock;
264 			pmd_populate(kvm->mm, pmd, new_ptep);
265 			new_ptep = NULL;
266 		}
267 		ptep = pte_offset_kernel(pmd, gpa);
268 		if (pte_present(*ptep)) {
269 			/* PTE was previously valid, so invalidate it */
270 			old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_PRESENT,
271 						      0, gpa, 0);
272 			kvmppc_radix_tlbie_page(kvm, gpa, 0);
273 			if (old & _PAGE_DIRTY)
274 				mark_page_dirty(kvm, gpa >> PAGE_SHIFT);
275 		}
276 		kvmppc_radix_set_pte_at(kvm, gpa, ptep, pte);
277 	} else {
278 		kvmppc_radix_set_pte_at(kvm, gpa, pmdp_ptep(pmd), pte);
279 	}
280 	ret = 0;
281 
282  out_unlock:
283 	spin_unlock(&kvm->mmu_lock);
284 	if (new_pud)
285 		pud_free(kvm->mm, new_pud);
286 	if (new_pmd)
287 		pmd_free(kvm->mm, new_pmd);
288 	if (new_ptep)
289 		kvmppc_pte_free(new_ptep);
290 	return ret;
291 }
292 
293 int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
294 				   unsigned long ea, unsigned long dsisr)
295 {
296 	struct kvm *kvm = vcpu->kvm;
297 	unsigned long mmu_seq, pte_size;
298 	unsigned long gpa, gfn, hva, pfn;
299 	struct kvm_memory_slot *memslot;
300 	struct page *page = NULL, *pages[1];
301 	long ret, npages, ok;
302 	unsigned int writing;
303 	struct vm_area_struct *vma;
304 	unsigned long flags;
305 	pte_t pte, *ptep;
306 	unsigned long pgflags;
307 	unsigned int shift, level;
308 
309 	/* Check for unusual errors */
310 	if (dsisr & DSISR_UNSUPP_MMU) {
311 		pr_err("KVM: Got unsupported MMU fault\n");
312 		return -EFAULT;
313 	}
314 	if (dsisr & DSISR_BADACCESS) {
315 		/* Reflect to the guest as DSI */
316 		pr_err("KVM: Got radix HV page fault with DSISR=%lx\n", dsisr);
317 		kvmppc_core_queue_data_storage(vcpu, ea, dsisr);
318 		return RESUME_GUEST;
319 	}
320 
321 	/* Translate the logical address and get the page */
322 	gpa = vcpu->arch.fault_gpa & ~0xfffUL;
323 	gpa &= ~0xF000000000000000ul;
324 	gfn = gpa >> PAGE_SHIFT;
325 	if (!(dsisr & DSISR_PGDIRFAULT))
326 		gpa |= ea & 0xfff;
327 	memslot = gfn_to_memslot(kvm, gfn);
328 
329 	/* No memslot means it's an emulated MMIO region */
330 	if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID)) {
331 		if (dsisr & (DSISR_PGDIRFAULT | DSISR_BADACCESS |
332 			     DSISR_SET_RC)) {
333 			/*
334 			 * Bad address in guest page table tree, or other
335 			 * unusual error - reflect it to the guest as DSI.
336 			 */
337 			kvmppc_core_queue_data_storage(vcpu, ea, dsisr);
338 			return RESUME_GUEST;
339 		}
340 		return kvmppc_hv_emulate_mmio(run, vcpu, gpa, ea,
341 					      dsisr & DSISR_ISSTORE);
342 	}
343 
344 	/* used to check for invalidations in progress */
345 	mmu_seq = kvm->mmu_notifier_seq;
346 	smp_rmb();
347 
348 	writing = (dsisr & DSISR_ISSTORE) != 0;
349 	hva = gfn_to_hva_memslot(memslot, gfn);
350 	if (dsisr & DSISR_SET_RC) {
351 		/*
352 		 * Need to set an R or C bit in the 2nd-level tables;
353 		 * if the relevant bits aren't already set in the linux
354 		 * page tables, fall through to do the gup_fast to
355 		 * set them in the linux page tables too.
356 		 */
357 		ok = 0;
358 		pgflags = _PAGE_ACCESSED;
359 		if (writing)
360 			pgflags |= _PAGE_DIRTY;
361 		local_irq_save(flags);
362 		ptep = __find_linux_pte_or_hugepte(current->mm->pgd, hva,
363 						   NULL, NULL);
364 		if (ptep) {
365 			pte = READ_ONCE(*ptep);
366 			if (pte_present(pte) &&
367 			    (pte_val(pte) & pgflags) == pgflags)
368 				ok = 1;
369 		}
370 		local_irq_restore(flags);
371 		if (ok) {
372 			spin_lock(&kvm->mmu_lock);
373 			if (mmu_notifier_retry(vcpu->kvm, mmu_seq)) {
374 				spin_unlock(&kvm->mmu_lock);
375 				return RESUME_GUEST;
376 			}
377 			ptep = __find_linux_pte_or_hugepte(kvm->arch.pgtable,
378 							gpa, NULL, &shift);
379 			if (ptep && pte_present(*ptep)) {
380 				kvmppc_radix_update_pte(kvm, ptep, 0, pgflags,
381 							gpa, shift);
382 				spin_unlock(&kvm->mmu_lock);
383 				return RESUME_GUEST;
384 			}
385 			spin_unlock(&kvm->mmu_lock);
386 		}
387 	}
388 
389 	ret = -EFAULT;
390 	pfn = 0;
391 	pte_size = PAGE_SIZE;
392 	pgflags = _PAGE_READ | _PAGE_EXEC;
393 	level = 0;
394 	npages = get_user_pages_fast(hva, 1, writing, pages);
395 	if (npages < 1) {
396 		/* Check if it's an I/O mapping */
397 		down_read(&current->mm->mmap_sem);
398 		vma = find_vma(current->mm, hva);
399 		if (vma && vma->vm_start <= hva && hva < vma->vm_end &&
400 		    (vma->vm_flags & VM_PFNMAP)) {
401 			pfn = vma->vm_pgoff +
402 				((hva - vma->vm_start) >> PAGE_SHIFT);
403 			pgflags = pgprot_val(vma->vm_page_prot);
404 		}
405 		up_read(&current->mm->mmap_sem);
406 		if (!pfn)
407 			return -EFAULT;
408 	} else {
409 		page = pages[0];
410 		pfn = page_to_pfn(page);
411 		if (PageHuge(page)) {
412 			page = compound_head(page);
413 			pte_size <<= compound_order(page);
414 			/* See if we can insert a 2MB large-page PTE here */
415 			if (pte_size >= PMD_SIZE &&
416 			    (gpa & PMD_MASK & PAGE_MASK) ==
417 			    (hva & PMD_MASK & PAGE_MASK)) {
418 				level = 1;
419 				pfn &= ~((PMD_SIZE >> PAGE_SHIFT) - 1);
420 			}
421 		}
422 		/* See if we can provide write access */
423 		if (writing) {
424 			/*
425 			 * We assume gup_fast has set dirty on the host PTE.
426 			 */
427 			pgflags |= _PAGE_WRITE;
428 		} else {
429 			local_irq_save(flags);
430 			ptep = __find_linux_pte_or_hugepte(current->mm->pgd,
431 							hva, NULL, NULL);
432 			if (ptep && pte_write(*ptep) && pte_dirty(*ptep))
433 				pgflags |= _PAGE_WRITE;
434 			local_irq_restore(flags);
435 		}
436 	}
437 
438 	/*
439 	 * Compute the PTE value that we need to insert.
440 	 */
441 	pgflags |= _PAGE_PRESENT | _PAGE_PTE | _PAGE_ACCESSED;
442 	if (pgflags & _PAGE_WRITE)
443 		pgflags |= _PAGE_DIRTY;
444 	pte = pfn_pte(pfn, __pgprot(pgflags));
445 
446 	/* Allocate space in the tree and write the PTE */
447 	ret = kvmppc_create_pte(kvm, pte, gpa, level, mmu_seq);
448 	if (ret == -EBUSY) {
449 		/*
450 		 * There's already a PMD where wanted to install a large page;
451 		 * for now, fall back to installing a small page.
452 		 */
453 		level = 0;
454 		pfn |= gfn & ((PMD_SIZE >> PAGE_SHIFT) - 1);
455 		pte = pfn_pte(pfn, __pgprot(pgflags));
456 		ret = kvmppc_create_pte(kvm, pte, gpa, level, mmu_seq);
457 	}
458 	if (ret == 0 || ret == -EAGAIN)
459 		ret = RESUME_GUEST;
460 
461 	if (page) {
462 		/*
463 		 * We drop pages[0] here, not page because page might
464 		 * have been set to the head page of a compound, but
465 		 * we have to drop the reference on the correct tail
466 		 * page to match the get inside gup()
467 		 */
468 		put_page(pages[0]);
469 	}
470 	return ret;
471 }
472 
473 static void mark_pages_dirty(struct kvm *kvm, struct kvm_memory_slot *memslot,
474 			     unsigned long gfn, unsigned int order)
475 {
476 	unsigned long i, limit;
477 	unsigned long *dp;
478 
479 	if (!memslot->dirty_bitmap)
480 		return;
481 	limit = 1ul << order;
482 	if (limit < BITS_PER_LONG) {
483 		for (i = 0; i < limit; ++i)
484 			mark_page_dirty(kvm, gfn + i);
485 		return;
486 	}
487 	dp = memslot->dirty_bitmap + (gfn - memslot->base_gfn);
488 	limit /= BITS_PER_LONG;
489 	for (i = 0; i < limit; ++i)
490 		*dp++ = ~0ul;
491 }
492 
493 /* Called with kvm->lock held */
494 int kvm_unmap_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
495 		    unsigned long gfn)
496 {
497 	pte_t *ptep;
498 	unsigned long gpa = gfn << PAGE_SHIFT;
499 	unsigned int shift;
500 	unsigned long old;
501 
502 	ptep = __find_linux_pte_or_hugepte(kvm->arch.pgtable, gpa,
503 					   NULL, &shift);
504 	if (ptep && pte_present(*ptep)) {
505 		old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_PRESENT, 0,
506 					      gpa, shift);
507 		kvmppc_radix_tlbie_page(kvm, gpa, shift);
508 		if (old & _PAGE_DIRTY) {
509 			if (!shift)
510 				mark_page_dirty(kvm, gfn);
511 			else
512 				mark_pages_dirty(kvm, memslot,
513 						 gfn, shift - PAGE_SHIFT);
514 		}
515 	}
516 	return 0;
517 }
518 
519 /* Called with kvm->lock held */
520 int kvm_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
521 		  unsigned long gfn)
522 {
523 	pte_t *ptep;
524 	unsigned long gpa = gfn << PAGE_SHIFT;
525 	unsigned int shift;
526 	int ref = 0;
527 
528 	ptep = __find_linux_pte_or_hugepte(kvm->arch.pgtable, gpa,
529 					   NULL, &shift);
530 	if (ptep && pte_present(*ptep) && pte_young(*ptep)) {
531 		kvmppc_radix_update_pte(kvm, ptep, _PAGE_ACCESSED, 0,
532 					gpa, shift);
533 		/* XXX need to flush tlb here? */
534 		ref = 1;
535 	}
536 	return ref;
537 }
538 
539 /* Called with kvm->lock held */
540 int kvm_test_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
541 		       unsigned long gfn)
542 {
543 	pte_t *ptep;
544 	unsigned long gpa = gfn << PAGE_SHIFT;
545 	unsigned int shift;
546 	int ref = 0;
547 
548 	ptep = __find_linux_pte_or_hugepte(kvm->arch.pgtable, gpa,
549 					   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_or_hugepte(kvm->arch.pgtable, gpa,
566 					   NULL, &shift);
567 	if (ptep && pte_present(*ptep) && pte_dirty(*ptep)) {
568 		ret = 1;
569 		if (shift)
570 			ret = 1 << (shift - PAGE_SHIFT);
571 		kvmppc_radix_update_pte(kvm, ptep, _PAGE_DIRTY, 0,
572 					gpa, shift);
573 		kvmppc_radix_tlbie_page(kvm, gpa, shift);
574 	}
575 	return ret;
576 }
577 
578 long kvmppc_hv_get_dirty_log_radix(struct kvm *kvm,
579 			struct kvm_memory_slot *memslot, unsigned long *map)
580 {
581 	unsigned long i, j;
582 	unsigned long n, *p;
583 	int npages;
584 
585 	/*
586 	 * Radix accumulates dirty bits in the first half of the
587 	 * memslot's dirty_bitmap area, for when pages are paged
588 	 * out or modified by the host directly.  Pick up these
589 	 * bits and add them to the map.
590 	 */
591 	n = kvm_dirty_bitmap_bytes(memslot) / sizeof(long);
592 	p = memslot->dirty_bitmap;
593 	for (i = 0; i < n; ++i)
594 		map[i] |= xchg(&p[i], 0);
595 
596 	for (i = 0; i < memslot->npages; i = j) {
597 		npages = kvm_radix_test_clear_dirty(kvm, memslot, i);
598 
599 		/*
600 		 * Note that if npages > 0 then i must be a multiple of npages,
601 		 * since huge pages are only used to back the guest at guest
602 		 * real addresses that are a multiple of their size.
603 		 * Since we have at most one PTE covering any given guest
604 		 * real address, if npages > 1 we can skip to i + npages.
605 		 */
606 		j = i + 1;
607 		if (npages)
608 			for (j = i; npages; ++j, --npages)
609 				__set_bit_le(j, map);
610 	}
611 	return 0;
612 }
613 
614 static void add_rmmu_ap_encoding(struct kvm_ppc_rmmu_info *info,
615 				 int psize, int *indexp)
616 {
617 	if (!mmu_psize_defs[psize].shift)
618 		return;
619 	info->ap_encodings[*indexp] = mmu_psize_defs[psize].shift |
620 		(mmu_psize_defs[psize].ap << 29);
621 	++(*indexp);
622 }
623 
624 int kvmhv_get_rmmu_info(struct kvm *kvm, struct kvm_ppc_rmmu_info *info)
625 {
626 	int i;
627 
628 	if (!radix_enabled())
629 		return -EINVAL;
630 	memset(info, 0, sizeof(*info));
631 
632 	/* 4k page size */
633 	info->geometries[0].page_shift = 12;
634 	info->geometries[0].level_bits[0] = 9;
635 	for (i = 1; i < 4; ++i)
636 		info->geometries[0].level_bits[i] = p9_supported_radix_bits[i];
637 	/* 64k page size */
638 	info->geometries[1].page_shift = 16;
639 	for (i = 0; i < 4; ++i)
640 		info->geometries[1].level_bits[i] = p9_supported_radix_bits[i];
641 
642 	i = 0;
643 	add_rmmu_ap_encoding(info, MMU_PAGE_4K, &i);
644 	add_rmmu_ap_encoding(info, MMU_PAGE_64K, &i);
645 	add_rmmu_ap_encoding(info, MMU_PAGE_2M, &i);
646 	add_rmmu_ap_encoding(info, MMU_PAGE_1G, &i);
647 
648 	return 0;
649 }
650 
651 int kvmppc_init_vm_radix(struct kvm *kvm)
652 {
653 	kvm->arch.pgtable = pgd_alloc(kvm->mm);
654 	if (!kvm->arch.pgtable)
655 		return -ENOMEM;
656 	return 0;
657 }
658 
659 void kvmppc_free_radix(struct kvm *kvm)
660 {
661 	unsigned long ig, iu, im;
662 	pte_t *pte;
663 	pmd_t *pmd;
664 	pud_t *pud;
665 	pgd_t *pgd;
666 
667 	if (!kvm->arch.pgtable)
668 		return;
669 	pgd = kvm->arch.pgtable;
670 	for (ig = 0; ig < PTRS_PER_PGD; ++ig, ++pgd) {
671 		if (!pgd_present(*pgd))
672 			continue;
673 		pud = pud_offset(pgd, 0);
674 		for (iu = 0; iu < PTRS_PER_PUD; ++iu, ++pud) {
675 			if (!pud_present(*pud))
676 				continue;
677 			pmd = pmd_offset(pud, 0);
678 			for (im = 0; im < PTRS_PER_PMD; ++im, ++pmd) {
679 				if (pmd_huge(*pmd)) {
680 					pmd_clear(pmd);
681 					continue;
682 				}
683 				if (!pmd_present(*pmd))
684 					continue;
685 				pte = pte_offset_map(pmd, 0);
686 				memset(pte, 0, sizeof(long) << PTE_INDEX_SIZE);
687 				kvmppc_pte_free(pte);
688 				pmd_clear(pmd);
689 			}
690 			pmd_free(kvm->mm, pmd_offset(pud, 0));
691 			pud_clear(pud);
692 		}
693 		pud_free(kvm->mm, pud_offset(pgd, 0));
694 		pgd_clear(pgd);
695 	}
696 	pgd_free(kvm->mm, kvm->arch.pgtable);
697 }
698 
699 static void pte_ctor(void *addr)
700 {
701 	memset(addr, 0, PTE_TABLE_SIZE);
702 }
703 
704 int kvmppc_radix_init(void)
705 {
706 	unsigned long size = sizeof(void *) << PTE_INDEX_SIZE;
707 
708 	kvm_pte_cache = kmem_cache_create("kvm-pte", size, size, 0, pte_ctor);
709 	if (!kvm_pte_cache)
710 		return -ENOMEM;
711 	return 0;
712 }
713 
714 void kvmppc_radix_exit(void)
715 {
716 	kmem_cache_destroy(kvm_pte_cache);
717 }
718