1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Secure pages management: Migration of pages between normal and secure
4 * memory of KVM guests.
5 *
6 * Copyright 2018 Bharata B Rao, IBM Corp. <bharata@linux.ibm.com>
7 */
8
9/*
10 * A pseries guest can be run as secure guest on Ultravisor-enabled
11 * POWER platforms. On such platforms, this driver will be used to manage
12 * the movement of guest pages between the normal memory managed by
13 * hypervisor (HV) and secure memory managed by Ultravisor (UV).
14 *
15 * The page-in or page-out requests from UV will come to HV as hcalls and
16 * HV will call back into UV via ultracalls to satisfy these page requests.
17 *
18 * Private ZONE_DEVICE memory equal to the amount of secure memory
19 * available in the platform for running secure guests is hotplugged.
20 * Whenever a page belonging to the guest becomes secure, a page from this
21 * private device memory is used to represent and track that secure page
22 * on the HV side. Some pages (like virtio buffers, VPA pages etc) are
23 * shared between UV and HV. However such pages aren't represented by
24 * device private memory and mappings to shared memory exist in both
25 * UV and HV page tables.
26 */
27
28/*
29 * Notes on locking
30 *
31 * kvm->arch.uvmem_lock is a per-guest lock that prevents concurrent
32 * page-in and page-out requests for the same GPA. Concurrent accesses
33 * can either come via UV (guest vCPUs requesting for same page)
34 * or when HV and guest simultaneously access the same page.
35 * This mutex serializes the migration of page from HV(normal) to
36 * UV(secure) and vice versa. So the serialization points are around
37 * migrate_vma routines and page-in/out routines.
38 *
39 * Per-guest mutex comes with a cost though. Mainly it serializes the
40 * fault path as page-out can occur when HV faults on accessing secure
41 * guest pages. Currently UV issues page-in requests for all the guest
42 * PFNs one at a time during early boot (UV_ESM uvcall), so this is
43 * not a cause for concern. Also currently the number of page-outs caused
44 * by HV touching secure pages is very very low. If an when UV supports
45 * overcommitting, then we might see concurrent guest driven page-outs.
46 *
47 * Locking order
48 *
49 * 1. kvm->srcu - Protects KVM memslots
50 * 2. kvm->mm->mmap_lock - find_vma, migrate_vma_pages and helpers, ksm_madvise
51 * 3. kvm->arch.uvmem_lock - protects read/writes to uvmem slots thus acting
52 * as sync-points for page-in/out
53 */
54
55/*
56 * Notes on page size
57 *
58 * Currently UV uses 2MB mappings internally, but will issue H_SVM_PAGE_IN
59 * and H_SVM_PAGE_OUT hcalls in PAGE_SIZE(64K) granularity. HV tracks
60 * secure GPAs at 64K page size and maintains one device PFN for each
61 * 64K secure GPA. UV_PAGE_IN and UV_PAGE_OUT calls by HV are also issued
62 * for 64K page at a time.
63 *
64 * HV faulting on secure pages: When HV touches any secure page, it
65 * faults and issues a UV_PAGE_OUT request with 64K page size. Currently
66 * UV splits and remaps the 2MB page if necessary and copies out the
67 * required 64K page contents.
68 *
69 * Shared pages: Whenever guest shares a secure page, UV will split and
70 * remap the 2MB page if required and issue H_SVM_PAGE_IN with 64K page size.
71 *
72 * HV invalidating a page: When a regular page belonging to secure
73 * guest gets unmapped, HV informs UV with UV_PAGE_INVAL of 64K
74 * page size. Using 64K page size is correct here because any non-secure
75 * page will essentially be of 64K page size. Splitting by UV during sharing
76 * and page-out ensures this.
77 *
78 * Page fault handling: When HV handles page fault of a page belonging
79 * to secure guest, it sends that to UV with a 64K UV_PAGE_IN request.
80 * Using 64K size is correct here too as UV would have split the 2MB page
81 * into 64k mappings and would have done page-outs earlier.
82 *
83 * In summary, the current secure pages handling code in HV assumes
84 * 64K page size and in fact fails any page-in/page-out requests of
85 * non-64K size upfront. If and when UV starts supporting multiple
86 * page-sizes, we need to break this assumption.
87 */
88
89#include <linux/pagemap.h>
90#include <linux/migrate.h>
91#include <linux/kvm_host.h>
92#include <linux/ksm.h>
93#include <linux/of.h>
94#include <linux/memremap.h>
95#include <asm/ultravisor.h>
96#include <asm/mman.h>
97#include <asm/kvm_ppc.h>
98#include <asm/kvm_book3s_uvmem.h>
99
100static struct dev_pagemap kvmppc_uvmem_pgmap;
101static unsigned long *kvmppc_uvmem_bitmap;
102static DEFINE_SPINLOCK(kvmppc_uvmem_bitmap_lock);
103
104/*
105 * States of a GFN
106 * ---------------
107 * The GFN can be in one of the following states.
108 *
109 * (a) Secure - The GFN is secure. The GFN is associated with
110 * a Secure VM, the contents of the GFN is not accessible
111 * to the Hypervisor. This GFN can be backed by a secure-PFN,
112 * or can be backed by a normal-PFN with contents encrypted.
113 * The former is true when the GFN is paged-in into the
114 * ultravisor. The latter is true when the GFN is paged-out
115 * of the ultravisor.
116 *
117 * (b) Shared - The GFN is shared. The GFN is associated with a
118 * a secure VM. The contents of the GFN is accessible to
119 * Hypervisor. This GFN is backed by a normal-PFN and its
120 * content is un-encrypted.
121 *
122 * (c) Normal - The GFN is a normal. The GFN is associated with
123 * a normal VM. The contents of the GFN is accessible to
124 * the Hypervisor. Its content is never encrypted.
125 *
126 * States of a VM.
127 * ---------------
128 *
129 * Normal VM: A VM whose contents are always accessible to
130 * the hypervisor. All its GFNs are normal-GFNs.
131 *
132 * Secure VM: A VM whose contents are not accessible to the
133 * hypervisor without the VM's consent. Its GFNs are
134 * either Shared-GFN or Secure-GFNs.
135 *
136 * Transient VM: A Normal VM that is transitioning to secure VM.
137 * The transition starts on successful return of
138 * H_SVM_INIT_START, and ends on successful return
139 * of H_SVM_INIT_DONE. This transient VM, can have GFNs
140 * in any of the three states; i.e Secure-GFN, Shared-GFN,
141 * and Normal-GFN. The VM never executes in this state
142 * in supervisor-mode.
143 *
144 * Memory slot State.
145 * -----------------------------
146 * The state of a memory slot mirrors the state of the
147 * VM the memory slot is associated with.
148 *
149 * VM State transition.
150 * --------------------
151 *
152 * A VM always starts in Normal Mode.
153 *
154 * H_SVM_INIT_START moves the VM into transient state. During this
155 * time the Ultravisor may request some of its GFNs to be shared or
156 * secured. So its GFNs can be in one of the three GFN states.
157 *
158 * H_SVM_INIT_DONE moves the VM entirely from transient state to
159 * secure-state. At this point any left-over normal-GFNs are
160 * transitioned to Secure-GFN.
161 *
162 * H_SVM_INIT_ABORT moves the transient VM back to normal VM.
163 * All its GFNs are moved to Normal-GFNs.
164 *
165 * UV_TERMINATE transitions the secure-VM back to normal-VM. All
166 * the secure-GFN and shared-GFNs are tranistioned to normal-GFN
167 * Note: The contents of the normal-GFN is undefined at this point.
168 *
169 * GFN state implementation:
170 * -------------------------
171 *
172 * Secure GFN is associated with a secure-PFN; also called uvmem_pfn,
173 * when the GFN is paged-in. Its pfn[] has KVMPPC_GFN_UVMEM_PFN flag
174 * set, and contains the value of the secure-PFN.
175 * It is associated with a normal-PFN; also called mem_pfn, when
176 * the GFN is pagedout. Its pfn[] has KVMPPC_GFN_MEM_PFN flag set.
177 * The value of the normal-PFN is not tracked.
178 *
179 * Shared GFN is associated with a normal-PFN. Its pfn[] has
180 * KVMPPC_UVMEM_SHARED_PFN flag set. The value of the normal-PFN
181 * is not tracked.
182 *
183 * Normal GFN is associated with normal-PFN. Its pfn[] has
184 * no flag set. The value of the normal-PFN is not tracked.
185 *
186 * Life cycle of a GFN
187 * --------------------
188 *
189 * --------------------------------------------------------------
190 * | | Share | Unshare | SVM |H_SVM_INIT_DONE|
191 * | |operation |operation | abort/ | |
192 * | | | | terminate | |
193 * -------------------------------------------------------------
194 * | | | | | |
195 * | Secure | Shared | Secure |Normal |Secure |
196 * | | | | | |
197 * | Shared | Shared | Secure |Normal |Shared |
198 * | | | | | |
199 * | Normal | Shared | Secure |Normal |Secure |
200 * --------------------------------------------------------------
201 *
202 * Life cycle of a VM
203 * --------------------
204 *
205 * --------------------------------------------------------------------
206 * | | start | H_SVM_ |H_SVM_ |H_SVM_ |UV_SVM_ |
207 * | | VM |INIT_START|INIT_DONE|INIT_ABORT |TERMINATE |
208 * | | | | | | |
209 * --------- ----------------------------------------------------------
210 * | | | | | | |
211 * | Normal | Normal | Transient|Error |Error |Normal |
212 * | | | | | | |
213 * | Secure | Error | Error |Error |Error |Normal |
214 * | | | | | | |
215 * |Transient| N/A | Error |Secure |Normal |Normal |
216 * --------------------------------------------------------------------
217 */
218
219#define KVMPPC_GFN_UVMEM_PFN (1UL << 63)
220#define KVMPPC_GFN_MEM_PFN (1UL << 62)
221#define KVMPPC_GFN_SHARED (1UL << 61)
222#define KVMPPC_GFN_SECURE (KVMPPC_GFN_UVMEM_PFN | KVMPPC_GFN_MEM_PFN)
223#define KVMPPC_GFN_FLAG_MASK (KVMPPC_GFN_SECURE | KVMPPC_GFN_SHARED)
224#define KVMPPC_GFN_PFN_MASK (~KVMPPC_GFN_FLAG_MASK)
225
226struct kvmppc_uvmem_slot {
227 struct list_head list;
228 unsigned long nr_pfns;
229 unsigned long base_pfn;
230 unsigned long *pfns;
231};
232struct kvmppc_uvmem_page_pvt {
233 struct kvm *kvm;
234 unsigned long gpa;
235 bool skip_page_out;
236 bool remove_gfn;
237};
238
239bool kvmppc_uvmem_available(void)
240{
241 /*
242 * If kvmppc_uvmem_bitmap != NULL, then there is an ultravisor
243 * and our data structures have been initialized successfully.
244 */
245 return !!kvmppc_uvmem_bitmap;
246}
247
248int kvmppc_uvmem_slot_init(struct kvm *kvm, const struct kvm_memory_slot *slot)
249{
250 struct kvmppc_uvmem_slot *p;
251
252 p = kzalloc(sizeof(*p), GFP_KERNEL);
253 if (!p)
254 return -ENOMEM;
255 p->pfns = vcalloc(slot->npages, sizeof(*p->pfns));
256 if (!p->pfns) {
257 kfree(objp: p);
258 return -ENOMEM;
259 }
260 p->nr_pfns = slot->npages;
261 p->base_pfn = slot->base_gfn;
262
263 mutex_lock(&kvm->arch.uvmem_lock);
264 list_add(new: &p->list, head: &kvm->arch.uvmem_pfns);
265 mutex_unlock(lock: &kvm->arch.uvmem_lock);
266
267 return 0;
268}
269
270/*
271 * All device PFNs are already released by the time we come here.
272 */
273void kvmppc_uvmem_slot_free(struct kvm *kvm, const struct kvm_memory_slot *slot)
274{
275 struct kvmppc_uvmem_slot *p, *next;
276
277 mutex_lock(&kvm->arch.uvmem_lock);
278 list_for_each_entry_safe(p, next, &kvm->arch.uvmem_pfns, list) {
279 if (p->base_pfn == slot->base_gfn) {
280 vfree(addr: p->pfns);
281 list_del(entry: &p->list);
282 kfree(objp: p);
283 break;
284 }
285 }
286 mutex_unlock(lock: &kvm->arch.uvmem_lock);
287}
288
289static void kvmppc_mark_gfn(unsigned long gfn, struct kvm *kvm,
290 unsigned long flag, unsigned long uvmem_pfn)
291{
292 struct kvmppc_uvmem_slot *p;
293
294 list_for_each_entry(p, &kvm->arch.uvmem_pfns, list) {
295 if (gfn >= p->base_pfn && gfn < p->base_pfn + p->nr_pfns) {
296 unsigned long index = gfn - p->base_pfn;
297
298 if (flag == KVMPPC_GFN_UVMEM_PFN)
299 p->pfns[index] = uvmem_pfn | flag;
300 else
301 p->pfns[index] = flag;
302 return;
303 }
304 }
305}
306
307/* mark the GFN as secure-GFN associated with @uvmem pfn device-PFN. */
308static void kvmppc_gfn_secure_uvmem_pfn(unsigned long gfn,
309 unsigned long uvmem_pfn, struct kvm *kvm)
310{
311 kvmppc_mark_gfn(gfn, kvm, KVMPPC_GFN_UVMEM_PFN, uvmem_pfn);
312}
313
314/* mark the GFN as secure-GFN associated with a memory-PFN. */
315static void kvmppc_gfn_secure_mem_pfn(unsigned long gfn, struct kvm *kvm)
316{
317 kvmppc_mark_gfn(gfn, kvm, KVMPPC_GFN_MEM_PFN, uvmem_pfn: 0);
318}
319
320/* mark the GFN as a shared GFN. */
321static void kvmppc_gfn_shared(unsigned long gfn, struct kvm *kvm)
322{
323 kvmppc_mark_gfn(gfn, kvm, KVMPPC_GFN_SHARED, uvmem_pfn: 0);
324}
325
326/* mark the GFN as a non-existent GFN. */
327static void kvmppc_gfn_remove(unsigned long gfn, struct kvm *kvm)
328{
329 kvmppc_mark_gfn(gfn, kvm, flag: 0, uvmem_pfn: 0);
330}
331
332/* return true, if the GFN is a secure-GFN backed by a secure-PFN */
333static bool kvmppc_gfn_is_uvmem_pfn(unsigned long gfn, struct kvm *kvm,
334 unsigned long *uvmem_pfn)
335{
336 struct kvmppc_uvmem_slot *p;
337
338 list_for_each_entry(p, &kvm->arch.uvmem_pfns, list) {
339 if (gfn >= p->base_pfn && gfn < p->base_pfn + p->nr_pfns) {
340 unsigned long index = gfn - p->base_pfn;
341
342 if (p->pfns[index] & KVMPPC_GFN_UVMEM_PFN) {
343 if (uvmem_pfn)
344 *uvmem_pfn = p->pfns[index] &
345 KVMPPC_GFN_PFN_MASK;
346 return true;
347 } else
348 return false;
349 }
350 }
351 return false;
352}
353
354/*
355 * starting from *gfn search for the next available GFN that is not yet
356 * transitioned to a secure GFN. return the value of that GFN in *gfn. If a
357 * GFN is found, return true, else return false
358 *
359 * Must be called with kvm->arch.uvmem_lock held.
360 */
361static bool kvmppc_next_nontransitioned_gfn(const struct kvm_memory_slot *memslot,
362 struct kvm *kvm, unsigned long *gfn)
363{
364 struct kvmppc_uvmem_slot *p = NULL, *iter;
365 bool ret = false;
366 unsigned long i;
367
368 list_for_each_entry(iter, &kvm->arch.uvmem_pfns, list)
369 if (*gfn >= iter->base_pfn && *gfn < iter->base_pfn + iter->nr_pfns) {
370 p = iter;
371 break;
372 }
373 if (!p)
374 return ret;
375 /*
376 * The code below assumes, one to one correspondence between
377 * kvmppc_uvmem_slot and memslot.
378 */
379 for (i = *gfn; i < p->base_pfn + p->nr_pfns; i++) {
380 unsigned long index = i - p->base_pfn;
381
382 if (!(p->pfns[index] & KVMPPC_GFN_FLAG_MASK)) {
383 *gfn = i;
384 ret = true;
385 break;
386 }
387 }
388 return ret;
389}
390
391static int kvmppc_memslot_page_merge(struct kvm *kvm,
392 const struct kvm_memory_slot *memslot, bool merge)
393{
394 unsigned long gfn = memslot->base_gfn;
395 unsigned long end, start = gfn_to_hva(kvm, gfn);
396 vm_flags_t vm_flags;
397 int ret = 0;
398 struct vm_area_struct *vma;
399 int merge_flag = (merge) ? MADV_MERGEABLE : MADV_UNMERGEABLE;
400
401 if (kvm_is_error_hva(addr: start))
402 return H_STATE;
403
404 end = start + (memslot->npages << PAGE_SHIFT);
405
406 mmap_write_lock(mm: kvm->mm);
407 do {
408 vma = find_vma_intersection(mm: kvm->mm, start_addr: start, end_addr: end);
409 if (!vma) {
410 ret = H_STATE;
411 break;
412 }
413 vma_start_write(vma);
414 /* Copy vm_flags to avoid partial modifications in ksm_madvise */
415 vm_flags = vma->vm_flags;
416 ret = ksm_madvise(vma, start: vma->vm_start, end: vma->vm_end,
417 advice: merge_flag, vm_flags: &vm_flags);
418 if (ret) {
419 ret = H_STATE;
420 break;
421 }
422 vm_flags_reset(vma, flags: vm_flags);
423 start = vma->vm_end;
424 } while (end > vma->vm_end);
425
426 mmap_write_unlock(mm: kvm->mm);
427 return ret;
428}
429
430static void __kvmppc_uvmem_memslot_delete(struct kvm *kvm,
431 const struct kvm_memory_slot *memslot)
432{
433 uv_unregister_mem_slot(kvm->arch.lpid, memslot->id);
434 kvmppc_uvmem_slot_free(kvm, slot: memslot);
435 kvmppc_memslot_page_merge(kvm, memslot, merge: true);
436}
437
438static int __kvmppc_uvmem_memslot_create(struct kvm *kvm,
439 const struct kvm_memory_slot *memslot)
440{
441 int ret = H_PARAMETER;
442
443 if (kvmppc_memslot_page_merge(kvm, memslot, merge: false))
444 return ret;
445
446 if (kvmppc_uvmem_slot_init(kvm, slot: memslot))
447 goto out1;
448
449 ret = uv_register_mem_slot(kvm->arch.lpid,
450 memslot->base_gfn << PAGE_SHIFT,
451 memslot->npages * PAGE_SIZE,
452 0, memslot->id);
453 if (ret < 0) {
454 ret = H_PARAMETER;
455 goto out;
456 }
457 return 0;
458out:
459 kvmppc_uvmem_slot_free(kvm, slot: memslot);
460out1:
461 kvmppc_memslot_page_merge(kvm, memslot, merge: true);
462 return ret;
463}
464
465unsigned long kvmppc_h_svm_init_start(struct kvm *kvm)
466{
467 struct kvm_memslots *slots;
468 struct kvm_memory_slot *memslot, *m;
469 int ret = H_SUCCESS;
470 int srcu_idx, bkt;
471
472 kvm->arch.secure_guest = KVMPPC_SECURE_INIT_START;
473
474 if (!kvmppc_uvmem_bitmap)
475 return H_UNSUPPORTED;
476
477 /* Only radix guests can be secure guests */
478 if (!kvm_is_radix(kvm))
479 return H_UNSUPPORTED;
480
481 /* NAK the transition to secure if not enabled */
482 if (!kvm->arch.svm_enabled)
483 return H_AUTHORITY;
484
485 srcu_idx = srcu_read_lock(ssp: &kvm->srcu);
486
487 /* register the memslot */
488 slots = kvm_memslots(kvm);
489 kvm_for_each_memslot(memslot, bkt, slots) {
490 ret = __kvmppc_uvmem_memslot_create(kvm, memslot);
491 if (ret)
492 break;
493 }
494
495 if (ret) {
496 slots = kvm_memslots(kvm);
497 kvm_for_each_memslot(m, bkt, slots) {
498 if (m == memslot)
499 break;
500 __kvmppc_uvmem_memslot_delete(kvm, memslot);
501 }
502 }
503
504 srcu_read_unlock(ssp: &kvm->srcu, idx: srcu_idx);
505 return ret;
506}
507
508/*
509 * Provision a new page on HV side and copy over the contents
510 * from secure memory using UV_PAGE_OUT uvcall.
511 * Caller must held kvm->arch.uvmem_lock.
512 */
513static int __kvmppc_svm_page_out(struct vm_area_struct *vma,
514 unsigned long start,
515 unsigned long end, unsigned long page_shift,
516 struct kvm *kvm, unsigned long gpa, struct page *fault_page)
517{
518 unsigned long src_pfn, dst_pfn = 0;
519 struct migrate_vma mig = { 0 };
520 struct page *dpage, *spage;
521 struct kvmppc_uvmem_page_pvt *pvt;
522 unsigned long pfn;
523 int ret = U_SUCCESS;
524
525 memset(&mig, 0, sizeof(mig));
526 mig.vma = vma;
527 mig.start = start;
528 mig.end = end;
529 mig.src = &src_pfn;
530 mig.dst = &dst_pfn;
531 mig.pgmap_owner = &kvmppc_uvmem_pgmap;
532 mig.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
533 mig.fault_page = fault_page;
534
535 /* The requested page is already paged-out, nothing to do */
536 if (!kvmppc_gfn_is_uvmem_pfn(gfn: gpa >> page_shift, kvm, NULL))
537 return ret;
538
539 ret = migrate_vma_setup(args: &mig);
540 if (ret)
541 return -1;
542
543 spage = migrate_pfn_to_page(mpfn: *mig.src);
544 if (!spage || !(*mig.src & MIGRATE_PFN_MIGRATE))
545 goto out_finalize;
546
547 if (!is_zone_device_page(page: spage))
548 goto out_finalize;
549
550 dpage = alloc_page_vma(GFP_HIGHUSER, vma, start);
551 if (!dpage) {
552 ret = -1;
553 goto out_finalize;
554 }
555
556 lock_page(page: dpage);
557 pvt = spage->zone_device_data;
558 pfn = page_to_pfn(dpage);
559
560 /*
561 * This function is used in two cases:
562 * - When HV touches a secure page, for which we do UV_PAGE_OUT
563 * - When a secure page is converted to shared page, we *get*
564 * the page to essentially unmap the device page. In this
565 * case we skip page-out.
566 */
567 if (!pvt->skip_page_out)
568 ret = uv_page_out(kvm->arch.lpid, pfn << page_shift,
569 gpa, 0, page_shift);
570
571 if (ret == U_SUCCESS)
572 *mig.dst = migrate_pfn(pfn);
573 else {
574 unlock_page(page: dpage);
575 __free_page(dpage);
576 goto out_finalize;
577 }
578
579 migrate_vma_pages(migrate: &mig);
580
581out_finalize:
582 migrate_vma_finalize(migrate: &mig);
583 return ret;
584}
585
586static inline int kvmppc_svm_page_out(struct vm_area_struct *vma,
587 unsigned long start, unsigned long end,
588 unsigned long page_shift,
589 struct kvm *kvm, unsigned long gpa,
590 struct page *fault_page)
591{
592 int ret;
593
594 mutex_lock(&kvm->arch.uvmem_lock);
595 ret = __kvmppc_svm_page_out(vma, start, end, page_shift, kvm, gpa,
596 fault_page);
597 mutex_unlock(lock: &kvm->arch.uvmem_lock);
598
599 return ret;
600}
601
602/*
603 * Drop device pages that we maintain for the secure guest
604 *
605 * We first mark the pages to be skipped from UV_PAGE_OUT when there
606 * is HV side fault on these pages. Next we *get* these pages, forcing
607 * fault on them, do fault time migration to replace the device PTEs in
608 * QEMU page table with normal PTEs from newly allocated pages.
609 */
610void kvmppc_uvmem_drop_pages(const struct kvm_memory_slot *slot,
611 struct kvm *kvm, bool skip_page_out)
612{
613 int i;
614 struct kvmppc_uvmem_page_pvt *pvt;
615 struct page *uvmem_page;
616 struct vm_area_struct *vma = NULL;
617 unsigned long uvmem_pfn, gfn;
618 unsigned long addr;
619
620 mmap_read_lock(mm: kvm->mm);
621
622 addr = slot->userspace_addr;
623
624 gfn = slot->base_gfn;
625 for (i = slot->npages; i; --i, ++gfn, addr += PAGE_SIZE) {
626
627 /* Fetch the VMA if addr is not in the latest fetched one */
628 if (!vma || addr >= vma->vm_end) {
629 vma = vma_lookup(mm: kvm->mm, addr);
630 if (!vma) {
631 pr_err("Can't find VMA for gfn:0x%lx\n", gfn);
632 break;
633 }
634 }
635
636 mutex_lock(&kvm->arch.uvmem_lock);
637
638 if (kvmppc_gfn_is_uvmem_pfn(gfn, kvm, uvmem_pfn: &uvmem_pfn)) {
639 uvmem_page = pfn_to_page(uvmem_pfn);
640 pvt = uvmem_page->zone_device_data;
641 pvt->skip_page_out = skip_page_out;
642 pvt->remove_gfn = true;
643
644 if (__kvmppc_svm_page_out(vma, start: addr, end: addr + PAGE_SIZE,
645 PAGE_SHIFT, kvm, gpa: pvt->gpa, NULL))
646 pr_err("Can't page out gpa:0x%lx addr:0x%lx\n",
647 pvt->gpa, addr);
648 } else {
649 /* Remove the shared flag if any */
650 kvmppc_gfn_remove(gfn, kvm);
651 }
652
653 mutex_unlock(lock: &kvm->arch.uvmem_lock);
654 }
655
656 mmap_read_unlock(mm: kvm->mm);
657}
658
659unsigned long kvmppc_h_svm_init_abort(struct kvm *kvm)
660{
661 int srcu_idx, bkt;
662 struct kvm_memory_slot *memslot;
663
664 /*
665 * Expect to be called only after INIT_START and before INIT_DONE.
666 * If INIT_DONE was completed, use normal VM termination sequence.
667 */
668 if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))
669 return H_UNSUPPORTED;
670
671 if (kvm->arch.secure_guest & KVMPPC_SECURE_INIT_DONE)
672 return H_STATE;
673
674 srcu_idx = srcu_read_lock(ssp: &kvm->srcu);
675
676 kvm_for_each_memslot(memslot, bkt, kvm_memslots(kvm))
677 kvmppc_uvmem_drop_pages(slot: memslot, kvm, skip_page_out: false);
678
679 srcu_read_unlock(ssp: &kvm->srcu, idx: srcu_idx);
680
681 kvm->arch.secure_guest = 0;
682 uv_svm_terminate(kvm->arch.lpid);
683
684 return H_PARAMETER;
685}
686
687/*
688 * Get a free device PFN from the pool
689 *
690 * Called when a normal page is moved to secure memory (UV_PAGE_IN). Device
691 * PFN will be used to keep track of the secure page on HV side.
692 *
693 * Called with kvm->arch.uvmem_lock held
694 */
695static struct page *kvmppc_uvmem_get_page(unsigned long gpa, struct kvm *kvm)
696{
697 struct page *dpage = NULL;
698 unsigned long bit, uvmem_pfn;
699 struct kvmppc_uvmem_page_pvt *pvt;
700 unsigned long pfn_last, pfn_first;
701
702 pfn_first = kvmppc_uvmem_pgmap.range.start >> PAGE_SHIFT;
703 pfn_last = pfn_first +
704 (range_len(range: &kvmppc_uvmem_pgmap.range) >> PAGE_SHIFT);
705
706 spin_lock(lock: &kvmppc_uvmem_bitmap_lock);
707 bit = find_first_zero_bit(addr: kvmppc_uvmem_bitmap,
708 size: pfn_last - pfn_first);
709 if (bit >= (pfn_last - pfn_first))
710 goto out;
711 bitmap_set(map: kvmppc_uvmem_bitmap, start: bit, nbits: 1);
712 spin_unlock(lock: &kvmppc_uvmem_bitmap_lock);
713
714 pvt = kzalloc(sizeof(*pvt), GFP_KERNEL);
715 if (!pvt)
716 goto out_clear;
717
718 uvmem_pfn = bit + pfn_first;
719 kvmppc_gfn_secure_uvmem_pfn(gfn: gpa >> PAGE_SHIFT, uvmem_pfn, kvm);
720
721 pvt->gpa = gpa;
722 pvt->kvm = kvm;
723
724 dpage = pfn_to_page(uvmem_pfn);
725 dpage->zone_device_data = pvt;
726 zone_device_page_init(page: dpage, pgmap: &kvmppc_uvmem_pgmap, order: 0);
727 return dpage;
728out_clear:
729 spin_lock(lock: &kvmppc_uvmem_bitmap_lock);
730 bitmap_clear(map: kvmppc_uvmem_bitmap, start: bit, nbits: 1);
731out:
732 spin_unlock(lock: &kvmppc_uvmem_bitmap_lock);
733 return NULL;
734}
735
736/*
737 * Alloc a PFN from private device memory pool. If @pagein is true,
738 * copy page from normal memory to secure memory using UV_PAGE_IN uvcall.
739 */
740static int kvmppc_svm_page_in(struct vm_area_struct *vma,
741 unsigned long start,
742 unsigned long end, unsigned long gpa, struct kvm *kvm,
743 unsigned long page_shift,
744 bool pagein)
745{
746 unsigned long src_pfn, dst_pfn = 0;
747 struct migrate_vma mig = { 0 };
748 struct page *spage;
749 unsigned long pfn;
750 struct page *dpage;
751 int ret = 0;
752
753 memset(&mig, 0, sizeof(mig));
754 mig.vma = vma;
755 mig.start = start;
756 mig.end = end;
757 mig.src = &src_pfn;
758 mig.dst = &dst_pfn;
759 mig.flags = MIGRATE_VMA_SELECT_SYSTEM;
760
761 ret = migrate_vma_setup(args: &mig);
762 if (ret)
763 return ret;
764
765 if (!(*mig.src & MIGRATE_PFN_MIGRATE)) {
766 ret = -1;
767 goto out_finalize;
768 }
769
770 dpage = kvmppc_uvmem_get_page(gpa, kvm);
771 if (!dpage) {
772 ret = -1;
773 goto out_finalize;
774 }
775
776 if (pagein) {
777 pfn = *mig.src >> MIGRATE_PFN_SHIFT;
778 spage = migrate_pfn_to_page(mpfn: *mig.src);
779 if (spage) {
780 ret = uv_page_in(kvm->arch.lpid, pfn << page_shift,
781 gpa, 0, page_shift);
782 if (ret)
783 goto out_finalize;
784 }
785 }
786
787 *mig.dst = migrate_pfn(page_to_pfn(dpage));
788 migrate_vma_pages(migrate: &mig);
789out_finalize:
790 migrate_vma_finalize(migrate: &mig);
791 return ret;
792}
793
794static int kvmppc_uv_migrate_mem_slot(struct kvm *kvm,
795 const struct kvm_memory_slot *memslot)
796{
797 unsigned long gfn = memslot->base_gfn;
798 struct vm_area_struct *vma;
799 unsigned long start, end;
800 int ret = 0;
801
802 mmap_read_lock(mm: kvm->mm);
803 mutex_lock(&kvm->arch.uvmem_lock);
804 while (kvmppc_next_nontransitioned_gfn(memslot, kvm, gfn: &gfn)) {
805 ret = H_STATE;
806 start = gfn_to_hva(kvm, gfn);
807 if (kvm_is_error_hva(addr: start))
808 break;
809
810 end = start + (1UL << PAGE_SHIFT);
811 vma = find_vma_intersection(mm: kvm->mm, start_addr: start, end_addr: end);
812 if (!vma || vma->vm_start > start || vma->vm_end < end)
813 break;
814
815 ret = kvmppc_svm_page_in(vma, start, end,
816 gpa: (gfn << PAGE_SHIFT), kvm, PAGE_SHIFT, pagein: false);
817 if (ret) {
818 ret = H_STATE;
819 break;
820 }
821
822 /* relinquish the cpu if needed */
823 cond_resched();
824 }
825 mutex_unlock(lock: &kvm->arch.uvmem_lock);
826 mmap_read_unlock(mm: kvm->mm);
827 return ret;
828}
829
830unsigned long kvmppc_h_svm_init_done(struct kvm *kvm)
831{
832 struct kvm_memslots *slots;
833 struct kvm_memory_slot *memslot;
834 int srcu_idx, bkt;
835 long ret = H_SUCCESS;
836
837 if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))
838 return H_UNSUPPORTED;
839
840 /* migrate any unmoved normal pfn to device pfns*/
841 srcu_idx = srcu_read_lock(ssp: &kvm->srcu);
842 slots = kvm_memslots(kvm);
843 kvm_for_each_memslot(memslot, bkt, slots) {
844 ret = kvmppc_uv_migrate_mem_slot(kvm, memslot);
845 if (ret) {
846 /*
847 * The pages will remain transitioned.
848 * Its the callers responsibility to
849 * terminate the VM, which will undo
850 * all state of the VM. Till then
851 * this VM is in a erroneous state.
852 * Its KVMPPC_SECURE_INIT_DONE will
853 * remain unset.
854 */
855 ret = H_STATE;
856 goto out;
857 }
858 }
859
860 kvm->arch.secure_guest |= KVMPPC_SECURE_INIT_DONE;
861 pr_info("LPID %lld went secure\n", kvm->arch.lpid);
862
863out:
864 srcu_read_unlock(ssp: &kvm->srcu, idx: srcu_idx);
865 return ret;
866}
867
868/*
869 * Shares the page with HV, thus making it a normal page.
870 *
871 * - If the page is already secure, then provision a new page and share
872 * - If the page is a normal page, share the existing page
873 *
874 * In the former case, uses dev_pagemap_ops.migrate_to_ram handler
875 * to unmap the device page from QEMU's page tables.
876 */
877static unsigned long kvmppc_share_page(struct kvm *kvm, unsigned long gpa,
878 unsigned long page_shift)
879{
880
881 int ret = H_PARAMETER;
882 struct page *page, *uvmem_page;
883 struct kvmppc_uvmem_page_pvt *pvt;
884 unsigned long gfn = gpa >> page_shift;
885 int srcu_idx;
886 unsigned long uvmem_pfn;
887
888 srcu_idx = srcu_read_lock(ssp: &kvm->srcu);
889 mutex_lock(&kvm->arch.uvmem_lock);
890 if (kvmppc_gfn_is_uvmem_pfn(gfn, kvm, uvmem_pfn: &uvmem_pfn)) {
891 uvmem_page = pfn_to_page(uvmem_pfn);
892 pvt = uvmem_page->zone_device_data;
893 pvt->skip_page_out = true;
894 /*
895 * do not drop the GFN. It is a valid GFN
896 * that is transitioned to a shared GFN.
897 */
898 pvt->remove_gfn = false;
899 }
900
901retry:
902 mutex_unlock(lock: &kvm->arch.uvmem_lock);
903 page = gfn_to_page(kvm, gfn);
904 if (!page)
905 goto out;
906
907 mutex_lock(&kvm->arch.uvmem_lock);
908 if (kvmppc_gfn_is_uvmem_pfn(gfn, kvm, uvmem_pfn: &uvmem_pfn)) {
909 uvmem_page = pfn_to_page(uvmem_pfn);
910 pvt = uvmem_page->zone_device_data;
911 pvt->skip_page_out = true;
912 pvt->remove_gfn = false; /* it continues to be a valid GFN */
913 kvm_release_page_unused(page);
914 goto retry;
915 }
916
917 if (!uv_page_in(kvm->arch.lpid, page_to_pfn(page) << page_shift, gpa, 0,
918 page_shift)) {
919 kvmppc_gfn_shared(gfn, kvm);
920 ret = H_SUCCESS;
921 }
922 kvm_release_page_clean(page);
923 mutex_unlock(lock: &kvm->arch.uvmem_lock);
924out:
925 srcu_read_unlock(ssp: &kvm->srcu, idx: srcu_idx);
926 return ret;
927}
928
929/*
930 * H_SVM_PAGE_IN: Move page from normal memory to secure memory.
931 *
932 * H_PAGE_IN_SHARED flag makes the page shared which means that the same
933 * memory in is visible from both UV and HV.
934 */
935unsigned long kvmppc_h_svm_page_in(struct kvm *kvm, unsigned long gpa,
936 unsigned long flags,
937 unsigned long page_shift)
938{
939 unsigned long start, end;
940 struct vm_area_struct *vma;
941 int srcu_idx;
942 unsigned long gfn = gpa >> page_shift;
943 int ret;
944
945 if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))
946 return H_UNSUPPORTED;
947
948 if (page_shift != PAGE_SHIFT)
949 return H_P3;
950
951 if (flags & ~H_PAGE_IN_SHARED)
952 return H_P2;
953
954 if (flags & H_PAGE_IN_SHARED)
955 return kvmppc_share_page(kvm, gpa, page_shift);
956
957 ret = H_PARAMETER;
958 srcu_idx = srcu_read_lock(ssp: &kvm->srcu);
959 mmap_read_lock(mm: kvm->mm);
960
961 start = gfn_to_hva(kvm, gfn);
962 if (kvm_is_error_hva(addr: start))
963 goto out;
964
965 mutex_lock(&kvm->arch.uvmem_lock);
966 /* Fail the page-in request of an already paged-in page */
967 if (kvmppc_gfn_is_uvmem_pfn(gfn, kvm, NULL))
968 goto out_unlock;
969
970 end = start + (1UL << page_shift);
971 vma = find_vma_intersection(mm: kvm->mm, start_addr: start, end_addr: end);
972 if (!vma || vma->vm_start > start || vma->vm_end < end)
973 goto out_unlock;
974
975 if (kvmppc_svm_page_in(vma, start, end, gpa, kvm, page_shift,
976 pagein: true))
977 goto out_unlock;
978
979 ret = H_SUCCESS;
980
981out_unlock:
982 mutex_unlock(lock: &kvm->arch.uvmem_lock);
983out:
984 mmap_read_unlock(mm: kvm->mm);
985 srcu_read_unlock(ssp: &kvm->srcu, idx: srcu_idx);
986 return ret;
987}
988
989
990/*
991 * Fault handler callback that gets called when HV touches any page that
992 * has been moved to secure memory, we ask UV to give back the page by
993 * issuing UV_PAGE_OUT uvcall.
994 *
995 * This eventually results in dropping of device PFN and the newly
996 * provisioned page/PFN gets populated in QEMU page tables.
997 */
998static vm_fault_t kvmppc_uvmem_migrate_to_ram(struct vm_fault *vmf)
999{
1000 struct kvmppc_uvmem_page_pvt *pvt = vmf->page->zone_device_data;
1001
1002 if (kvmppc_svm_page_out(vma: vmf->vma, start: vmf->address,
1003 end: vmf->address + PAGE_SIZE, PAGE_SHIFT,
1004 kvm: pvt->kvm, gpa: pvt->gpa, fault_page: vmf->page))
1005 return VM_FAULT_SIGBUS;
1006 else
1007 return 0;
1008}
1009
1010/*
1011 * Release the device PFN back to the pool
1012 *
1013 * Gets called when secure GFN tranistions from a secure-PFN
1014 * to a normal PFN during H_SVM_PAGE_OUT.
1015 * Gets called with kvm->arch.uvmem_lock held.
1016 */
1017static void kvmppc_uvmem_folio_free(struct folio *folio)
1018{
1019 struct page *page = &folio->page;
1020 unsigned long pfn = page_to_pfn(page) -
1021 (kvmppc_uvmem_pgmap.range.start >> PAGE_SHIFT);
1022 struct kvmppc_uvmem_page_pvt *pvt;
1023
1024 spin_lock(lock: &kvmppc_uvmem_bitmap_lock);
1025 bitmap_clear(map: kvmppc_uvmem_bitmap, start: pfn, nbits: 1);
1026 spin_unlock(lock: &kvmppc_uvmem_bitmap_lock);
1027
1028 pvt = page->zone_device_data;
1029 page->zone_device_data = NULL;
1030 if (pvt->remove_gfn)
1031 kvmppc_gfn_remove(gfn: pvt->gpa >> PAGE_SHIFT, kvm: pvt->kvm);
1032 else
1033 kvmppc_gfn_secure_mem_pfn(gfn: pvt->gpa >> PAGE_SHIFT, kvm: pvt->kvm);
1034 kfree(objp: pvt);
1035}
1036
1037static const struct dev_pagemap_ops kvmppc_uvmem_ops = {
1038 .folio_free = kvmppc_uvmem_folio_free,
1039 .migrate_to_ram = kvmppc_uvmem_migrate_to_ram,
1040};
1041
1042/*
1043 * H_SVM_PAGE_OUT: Move page from secure memory to normal memory.
1044 */
1045unsigned long
1046kvmppc_h_svm_page_out(struct kvm *kvm, unsigned long gpa,
1047 unsigned long flags, unsigned long page_shift)
1048{
1049 unsigned long gfn = gpa >> page_shift;
1050 unsigned long start, end;
1051 struct vm_area_struct *vma;
1052 int srcu_idx;
1053 int ret;
1054
1055 if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))
1056 return H_UNSUPPORTED;
1057
1058 if (page_shift != PAGE_SHIFT)
1059 return H_P3;
1060
1061 if (flags)
1062 return H_P2;
1063
1064 ret = H_PARAMETER;
1065 srcu_idx = srcu_read_lock(ssp: &kvm->srcu);
1066 mmap_read_lock(mm: kvm->mm);
1067 start = gfn_to_hva(kvm, gfn);
1068 if (kvm_is_error_hva(addr: start))
1069 goto out;
1070
1071 end = start + (1UL << page_shift);
1072 vma = find_vma_intersection(mm: kvm->mm, start_addr: start, end_addr: end);
1073 if (!vma || vma->vm_start > start || vma->vm_end < end)
1074 goto out;
1075
1076 if (!kvmppc_svm_page_out(vma, start, end, page_shift, kvm, gpa, NULL))
1077 ret = H_SUCCESS;
1078out:
1079 mmap_read_unlock(mm: kvm->mm);
1080 srcu_read_unlock(ssp: &kvm->srcu, idx: srcu_idx);
1081 return ret;
1082}
1083
1084int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gfn)
1085{
1086 struct page *page;
1087 int ret = U_SUCCESS;
1088
1089 page = gfn_to_page(kvm, gfn);
1090 if (!page)
1091 return -EFAULT;
1092
1093 mutex_lock(&kvm->arch.uvmem_lock);
1094 if (kvmppc_gfn_is_uvmem_pfn(gfn, kvm, NULL))
1095 goto out;
1096
1097 ret = uv_page_in(kvm->arch.lpid, page_to_pfn(page) << PAGE_SHIFT,
1098 gfn << PAGE_SHIFT, 0, PAGE_SHIFT);
1099out:
1100 kvm_release_page_clean(page);
1101 mutex_unlock(lock: &kvm->arch.uvmem_lock);
1102 return (ret == U_SUCCESS) ? RESUME_GUEST : -EFAULT;
1103}
1104
1105int kvmppc_uvmem_memslot_create(struct kvm *kvm, const struct kvm_memory_slot *new)
1106{
1107 int ret = __kvmppc_uvmem_memslot_create(kvm, memslot: new);
1108
1109 if (!ret)
1110 ret = kvmppc_uv_migrate_mem_slot(kvm, memslot: new);
1111
1112 return ret;
1113}
1114
1115void kvmppc_uvmem_memslot_delete(struct kvm *kvm, const struct kvm_memory_slot *old)
1116{
1117 __kvmppc_uvmem_memslot_delete(kvm, memslot: old);
1118}
1119
1120static u64 kvmppc_get_secmem_size(void)
1121{
1122 struct device_node *np;
1123 int i, len;
1124 const __be32 *prop;
1125 u64 size = 0;
1126
1127 /*
1128 * First try the new ibm,secure-memory nodes which supersede the
1129 * secure-memory-ranges property.
1130 * If we found some, no need to read the deprecated ones.
1131 */
1132 for_each_compatible_node(np, NULL, "ibm,secure-memory") {
1133 prop = of_get_property(node: np, name: "reg", lenp: &len);
1134 if (!prop)
1135 continue;
1136 size += of_read_number(cell: prop + 2, size: 2);
1137 }
1138 if (size)
1139 return size;
1140
1141 np = of_find_compatible_node(NULL, NULL, compat: "ibm,uv-firmware");
1142 if (!np)
1143 goto out;
1144
1145 prop = of_get_property(node: np, name: "secure-memory-ranges", lenp: &len);
1146 if (!prop)
1147 goto out_put;
1148
1149 for (i = 0; i < len / (sizeof(*prop) * 4); i++)
1150 size += of_read_number(cell: prop + (i * 4) + 2, size: 2);
1151
1152out_put:
1153 of_node_put(node: np);
1154out:
1155 return size;
1156}
1157
1158int kvmppc_uvmem_init(void)
1159{
1160 int ret = 0;
1161 unsigned long size;
1162 struct resource *res;
1163 void *addr;
1164 unsigned long pfn_last, pfn_first;
1165
1166 size = kvmppc_get_secmem_size();
1167 if (!size) {
1168 /*
1169 * Don't fail the initialization of kvm-hv module if
1170 * the platform doesn't export ibm,uv-firmware node.
1171 * Let normal guests run on such PEF-disabled platform.
1172 */
1173 pr_info("KVMPPC-UVMEM: No support for secure guests\n");
1174 goto out;
1175 }
1176
1177 res = request_free_mem_region(base: &iomem_resource, size, name: "kvmppc_uvmem");
1178 if (IS_ERR(ptr: res)) {
1179 ret = PTR_ERR(ptr: res);
1180 goto out;
1181 }
1182
1183 kvmppc_uvmem_pgmap.type = MEMORY_DEVICE_PRIVATE;
1184 kvmppc_uvmem_pgmap.range.start = res->start;
1185 kvmppc_uvmem_pgmap.range.end = res->end;
1186 kvmppc_uvmem_pgmap.nr_range = 1;
1187 kvmppc_uvmem_pgmap.ops = &kvmppc_uvmem_ops;
1188 /* just one global instance: */
1189 kvmppc_uvmem_pgmap.owner = &kvmppc_uvmem_pgmap;
1190 addr = memremap_pages(pgmap: &kvmppc_uvmem_pgmap, NUMA_NO_NODE);
1191 if (IS_ERR(ptr: addr)) {
1192 ret = PTR_ERR(ptr: addr);
1193 goto out_free_region;
1194 }
1195
1196 pfn_first = res->start >> PAGE_SHIFT;
1197 pfn_last = pfn_first + (resource_size(res) >> PAGE_SHIFT);
1198 kvmppc_uvmem_bitmap = bitmap_zalloc(nbits: pfn_last - pfn_first, GFP_KERNEL);
1199 if (!kvmppc_uvmem_bitmap) {
1200 ret = -ENOMEM;
1201 goto out_unmap;
1202 }
1203
1204 pr_info("KVMPPC-UVMEM: Secure Memory size 0x%lx\n", size);
1205 return ret;
1206out_unmap:
1207 memunmap_pages(pgmap: &kvmppc_uvmem_pgmap);
1208out_free_region:
1209 release_mem_region(res->start, size);
1210out:
1211 return ret;
1212}
1213
1214void kvmppc_uvmem_free(void)
1215{
1216 if (!kvmppc_uvmem_bitmap)
1217 return;
1218
1219 memunmap_pages(pgmap: &kvmppc_uvmem_pgmap);
1220 release_mem_region(kvmppc_uvmem_pgmap.range.start,
1221 range_len(&kvmppc_uvmem_pgmap.range));
1222 bitmap_free(bitmap: kvmppc_uvmem_bitmap);
1223}
1224

source code of linux/arch/powerpc/kvm/book3s_hv_uvmem.c