1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright(c) 2016-20 Intel Corporation. */
3
4 #include <linux/file.h>
5 #include <linux/freezer.h>
6 #include <linux/highmem.h>
7 #include <linux/kthread.h>
8 #include <linux/miscdevice.h>
9 #include <linux/node.h>
10 #include <linux/pagemap.h>
11 #include <linux/ratelimit.h>
12 #include <linux/sched/mm.h>
13 #include <linux/sched/signal.h>
14 #include <linux/slab.h>
15 #include <linux/sysfs.h>
16 #include <asm/sgx.h>
17 #include "driver.h"
18 #include "encl.h"
19 #include "encls.h"
20
21 struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
22 static int sgx_nr_epc_sections;
23 static struct task_struct *ksgxd_tsk;
24 static DECLARE_WAIT_QUEUE_HEAD(ksgxd_waitq);
25 static DEFINE_XARRAY(sgx_epc_address_space);
26
27 /*
28 * These variables are part of the state of the reclaimer, and must be accessed
29 * with sgx_reclaimer_lock acquired.
30 */
31 static LIST_HEAD(sgx_active_page_list);
32 static DEFINE_SPINLOCK(sgx_reclaimer_lock);
33
34 static atomic_long_t sgx_nr_free_pages = ATOMIC_LONG_INIT(0);
35
36 /* Nodes with one or more EPC sections. */
37 static nodemask_t sgx_numa_mask;
38
39 /*
40 * Array with one list_head for each possible NUMA node. Each
41 * list contains all the sgx_epc_section's which are on that
42 * node.
43 */
44 static struct sgx_numa_node *sgx_numa_nodes;
45
46 static LIST_HEAD(sgx_dirty_page_list);
47
48 /*
49 * Reset post-kexec EPC pages to the uninitialized state. The pages are removed
50 * from the input list, and made available for the page allocator. SECS pages
51 * prepending their children in the input list are left intact.
52 *
53 * Return 0 when sanitization was successful or kthread was stopped, and the
54 * number of unsanitized pages otherwise.
55 */
__sgx_sanitize_pages(struct list_head * dirty_page_list)56 static unsigned long __sgx_sanitize_pages(struct list_head *dirty_page_list)
57 {
58 unsigned long left_dirty = 0;
59 struct sgx_epc_page *page;
60 LIST_HEAD(dirty);
61 int ret;
62
63 /* dirty_page_list is thread-local, no need for a lock: */
64 while (!list_empty(dirty_page_list)) {
65 if (kthread_should_stop())
66 return 0;
67
68 page = list_first_entry(dirty_page_list, struct sgx_epc_page, list);
69
70 /*
71 * Checking page->poison without holding the node->lock
72 * is racy, but losing the race (i.e. poison is set just
73 * after the check) just means __eremove() will be uselessly
74 * called for a page that sgx_free_epc_page() will put onto
75 * the node->sgx_poison_page_list later.
76 */
77 if (page->poison) {
78 struct sgx_epc_section *section = &sgx_epc_sections[page->section];
79 struct sgx_numa_node *node = section->node;
80
81 spin_lock(&node->lock);
82 list_move(&page->list, &node->sgx_poison_page_list);
83 spin_unlock(&node->lock);
84
85 continue;
86 }
87
88 ret = __eremove(sgx_get_epc_virt_addr(page));
89 if (!ret) {
90 /*
91 * page is now sanitized. Make it available via the SGX
92 * page allocator:
93 */
94 list_del(&page->list);
95 sgx_free_epc_page(page);
96 } else {
97 /* The page is not yet clean - move to the dirty list. */
98 list_move_tail(&page->list, &dirty);
99 left_dirty++;
100 }
101
102 cond_resched();
103 }
104
105 list_splice(&dirty, dirty_page_list);
106 return left_dirty;
107 }
108
sgx_reclaimer_age(struct sgx_epc_page * epc_page)109 static bool sgx_reclaimer_age(struct sgx_epc_page *epc_page)
110 {
111 struct sgx_encl_page *page = epc_page->owner;
112 struct sgx_encl *encl = page->encl;
113 struct sgx_encl_mm *encl_mm;
114 bool ret = true;
115 int idx;
116
117 idx = srcu_read_lock(&encl->srcu);
118
119 list_for_each_entry_rcu(encl_mm, &encl->mm_list, list) {
120 if (!mmget_not_zero(encl_mm->mm))
121 continue;
122
123 mmap_read_lock(encl_mm->mm);
124 ret = !sgx_encl_test_and_clear_young(encl_mm->mm, page);
125 mmap_read_unlock(encl_mm->mm);
126
127 mmput_async(encl_mm->mm);
128
129 if (!ret)
130 break;
131 }
132
133 srcu_read_unlock(&encl->srcu, idx);
134
135 if (!ret)
136 return false;
137
138 return true;
139 }
140
sgx_reclaimer_block(struct sgx_epc_page * epc_page)141 static void sgx_reclaimer_block(struct sgx_epc_page *epc_page)
142 {
143 struct sgx_encl_page *page = epc_page->owner;
144 unsigned long addr = page->desc & PAGE_MASK;
145 struct sgx_encl *encl = page->encl;
146 int ret;
147
148 sgx_zap_enclave_ptes(encl, addr);
149
150 mutex_lock(&encl->lock);
151
152 ret = __eblock(sgx_get_epc_virt_addr(epc_page));
153 if (encls_failed(ret))
154 ENCLS_WARN(ret, "EBLOCK");
155
156 mutex_unlock(&encl->lock);
157 }
158
__sgx_encl_ewb(struct sgx_epc_page * epc_page,void * va_slot,struct sgx_backing * backing)159 static int __sgx_encl_ewb(struct sgx_epc_page *epc_page, void *va_slot,
160 struct sgx_backing *backing)
161 {
162 struct sgx_pageinfo pginfo;
163 int ret;
164
165 pginfo.addr = 0;
166 pginfo.secs = 0;
167
168 pginfo.contents = (unsigned long)kmap_atomic(backing->contents);
169 pginfo.metadata = (unsigned long)kmap_atomic(backing->pcmd) +
170 backing->pcmd_offset;
171
172 ret = __ewb(&pginfo, sgx_get_epc_virt_addr(epc_page), va_slot);
173 set_page_dirty(backing->pcmd);
174 set_page_dirty(backing->contents);
175
176 kunmap_atomic((void *)(unsigned long)(pginfo.metadata -
177 backing->pcmd_offset));
178 kunmap_atomic((void *)(unsigned long)pginfo.contents);
179
180 return ret;
181 }
182
sgx_ipi_cb(void * info)183 void sgx_ipi_cb(void *info)
184 {
185 }
186
187 /*
188 * Swap page to the regular memory transformed to the blocked state by using
189 * EBLOCK, which means that it can no longer be referenced (no new TLB entries).
190 *
191 * The first trial just tries to write the page assuming that some other thread
192 * has reset the count for threads inside the enclave by using ETRACK, and
193 * previous thread count has been zeroed out. The second trial calls ETRACK
194 * before EWB. If that fails we kick all the HW threads out, and then do EWB,
195 * which should be guaranteed the succeed.
196 */
sgx_encl_ewb(struct sgx_epc_page * epc_page,struct sgx_backing * backing)197 static void sgx_encl_ewb(struct sgx_epc_page *epc_page,
198 struct sgx_backing *backing)
199 {
200 struct sgx_encl_page *encl_page = epc_page->owner;
201 struct sgx_encl *encl = encl_page->encl;
202 struct sgx_va_page *va_page;
203 unsigned int va_offset;
204 void *va_slot;
205 int ret;
206
207 encl_page->desc &= ~SGX_ENCL_PAGE_BEING_RECLAIMED;
208
209 va_page = list_first_entry(&encl->va_pages, struct sgx_va_page,
210 list);
211 va_offset = sgx_alloc_va_slot(va_page);
212 va_slot = sgx_get_epc_virt_addr(va_page->epc_page) + va_offset;
213 if (sgx_va_page_full(va_page))
214 list_move_tail(&va_page->list, &encl->va_pages);
215
216 ret = __sgx_encl_ewb(epc_page, va_slot, backing);
217 if (ret == SGX_NOT_TRACKED) {
218 ret = __etrack(sgx_get_epc_virt_addr(encl->secs.epc_page));
219 if (ret) {
220 if (encls_failed(ret))
221 ENCLS_WARN(ret, "ETRACK");
222 }
223
224 ret = __sgx_encl_ewb(epc_page, va_slot, backing);
225 if (ret == SGX_NOT_TRACKED) {
226 /*
227 * Slow path, send IPIs to kick cpus out of the
228 * enclave. Note, it's imperative that the cpu
229 * mask is generated *after* ETRACK, else we'll
230 * miss cpus that entered the enclave between
231 * generating the mask and incrementing epoch.
232 */
233 on_each_cpu_mask(sgx_encl_cpumask(encl),
234 sgx_ipi_cb, NULL, 1);
235 ret = __sgx_encl_ewb(epc_page, va_slot, backing);
236 }
237 }
238
239 if (ret) {
240 if (encls_failed(ret))
241 ENCLS_WARN(ret, "EWB");
242
243 sgx_free_va_slot(va_page, va_offset);
244 } else {
245 encl_page->desc |= va_offset;
246 encl_page->va_page = va_page;
247 }
248 }
249
sgx_reclaimer_write(struct sgx_epc_page * epc_page,struct sgx_backing * backing)250 static void sgx_reclaimer_write(struct sgx_epc_page *epc_page,
251 struct sgx_backing *backing)
252 {
253 struct sgx_encl_page *encl_page = epc_page->owner;
254 struct sgx_encl *encl = encl_page->encl;
255 struct sgx_backing secs_backing;
256 int ret;
257
258 mutex_lock(&encl->lock);
259
260 sgx_encl_ewb(epc_page, backing);
261 encl_page->epc_page = NULL;
262 encl->secs_child_cnt--;
263 sgx_encl_put_backing(backing);
264
265 if (!encl->secs_child_cnt && test_bit(SGX_ENCL_INITIALIZED, &encl->flags)) {
266 ret = sgx_encl_alloc_backing(encl, PFN_DOWN(encl->size),
267 &secs_backing);
268 if (ret)
269 goto out;
270
271 sgx_encl_ewb(encl->secs.epc_page, &secs_backing);
272
273 sgx_encl_free_epc_page(encl->secs.epc_page);
274 encl->secs.epc_page = NULL;
275
276 sgx_encl_put_backing(&secs_backing);
277 }
278
279 out:
280 mutex_unlock(&encl->lock);
281 }
282
283 /*
284 * Take a fixed number of pages from the head of the active page pool and
285 * reclaim them to the enclave's private shmem files. Skip the pages, which have
286 * been accessed since the last scan. Move those pages to the tail of active
287 * page pool so that the pages get scanned in LRU like fashion.
288 *
289 * Batch process a chunk of pages (at the moment 16) in order to degrade amount
290 * of IPI's and ETRACK's potentially required. sgx_encl_ewb() does degrade a bit
291 * among the HW threads with three stage EWB pipeline (EWB, ETRACK + EWB and IPI
292 * + EWB) but not sufficiently. Reclaiming one page at a time would also be
293 * problematic as it would increase the lock contention too much, which would
294 * halt forward progress.
295 */
sgx_reclaim_pages(void)296 static void sgx_reclaim_pages(void)
297 {
298 struct sgx_epc_page *chunk[SGX_NR_TO_SCAN];
299 struct sgx_backing backing[SGX_NR_TO_SCAN];
300 struct sgx_encl_page *encl_page;
301 struct sgx_epc_page *epc_page;
302 pgoff_t page_index;
303 int cnt = 0;
304 int ret;
305 int i;
306
307 spin_lock(&sgx_reclaimer_lock);
308 for (i = 0; i < SGX_NR_TO_SCAN; i++) {
309 if (list_empty(&sgx_active_page_list))
310 break;
311
312 epc_page = list_first_entry(&sgx_active_page_list,
313 struct sgx_epc_page, list);
314 list_del_init(&epc_page->list);
315 encl_page = epc_page->owner;
316
317 if (kref_get_unless_zero(&encl_page->encl->refcount) != 0)
318 chunk[cnt++] = epc_page;
319 else
320 /* The owner is freeing the page. No need to add the
321 * page back to the list of reclaimable pages.
322 */
323 epc_page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
324 }
325 spin_unlock(&sgx_reclaimer_lock);
326
327 for (i = 0; i < cnt; i++) {
328 epc_page = chunk[i];
329 encl_page = epc_page->owner;
330
331 if (!sgx_reclaimer_age(epc_page))
332 goto skip;
333
334 page_index = PFN_DOWN(encl_page->desc - encl_page->encl->base);
335
336 mutex_lock(&encl_page->encl->lock);
337 ret = sgx_encl_alloc_backing(encl_page->encl, page_index, &backing[i]);
338 if (ret) {
339 mutex_unlock(&encl_page->encl->lock);
340 goto skip;
341 }
342
343 encl_page->desc |= SGX_ENCL_PAGE_BEING_RECLAIMED;
344 mutex_unlock(&encl_page->encl->lock);
345 continue;
346
347 skip:
348 spin_lock(&sgx_reclaimer_lock);
349 list_add_tail(&epc_page->list, &sgx_active_page_list);
350 spin_unlock(&sgx_reclaimer_lock);
351
352 kref_put(&encl_page->encl->refcount, sgx_encl_release);
353
354 chunk[i] = NULL;
355 }
356
357 for (i = 0; i < cnt; i++) {
358 epc_page = chunk[i];
359 if (epc_page)
360 sgx_reclaimer_block(epc_page);
361 }
362
363 for (i = 0; i < cnt; i++) {
364 epc_page = chunk[i];
365 if (!epc_page)
366 continue;
367
368 encl_page = epc_page->owner;
369 sgx_reclaimer_write(epc_page, &backing[i]);
370
371 kref_put(&encl_page->encl->refcount, sgx_encl_release);
372 epc_page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
373
374 sgx_free_epc_page(epc_page);
375 }
376 }
377
sgx_should_reclaim(unsigned long watermark)378 static bool sgx_should_reclaim(unsigned long watermark)
379 {
380 return atomic_long_read(&sgx_nr_free_pages) < watermark &&
381 !list_empty(&sgx_active_page_list);
382 }
383
384 /*
385 * sgx_reclaim_direct() should be called (without enclave's mutex held)
386 * in locations where SGX memory resources might be low and might be
387 * needed in order to make forward progress.
388 */
sgx_reclaim_direct(void)389 void sgx_reclaim_direct(void)
390 {
391 if (sgx_should_reclaim(SGX_NR_LOW_PAGES))
392 sgx_reclaim_pages();
393 }
394
ksgxd(void * p)395 static int ksgxd(void *p)
396 {
397 set_freezable();
398
399 /*
400 * Sanitize pages in order to recover from kexec(). The 2nd pass is
401 * required for SECS pages, whose child pages blocked EREMOVE.
402 */
403 __sgx_sanitize_pages(&sgx_dirty_page_list);
404 WARN_ON(__sgx_sanitize_pages(&sgx_dirty_page_list));
405
406 while (!kthread_should_stop()) {
407 if (try_to_freeze())
408 continue;
409
410 wait_event_freezable(ksgxd_waitq,
411 kthread_should_stop() ||
412 sgx_should_reclaim(SGX_NR_HIGH_PAGES));
413
414 if (sgx_should_reclaim(SGX_NR_HIGH_PAGES))
415 sgx_reclaim_pages();
416
417 cond_resched();
418 }
419
420 return 0;
421 }
422
sgx_page_reclaimer_init(void)423 static bool __init sgx_page_reclaimer_init(void)
424 {
425 struct task_struct *tsk;
426
427 tsk = kthread_run(ksgxd, NULL, "ksgxd");
428 if (IS_ERR(tsk))
429 return false;
430
431 ksgxd_tsk = tsk;
432
433 return true;
434 }
435
current_is_ksgxd(void)436 bool current_is_ksgxd(void)
437 {
438 return current == ksgxd_tsk;
439 }
440
__sgx_alloc_epc_page_from_node(int nid)441 static struct sgx_epc_page *__sgx_alloc_epc_page_from_node(int nid)
442 {
443 struct sgx_numa_node *node = &sgx_numa_nodes[nid];
444 struct sgx_epc_page *page = NULL;
445
446 spin_lock(&node->lock);
447
448 if (list_empty(&node->free_page_list)) {
449 spin_unlock(&node->lock);
450 return NULL;
451 }
452
453 page = list_first_entry(&node->free_page_list, struct sgx_epc_page, list);
454 list_del_init(&page->list);
455 page->flags = 0;
456
457 spin_unlock(&node->lock);
458 atomic_long_dec(&sgx_nr_free_pages);
459
460 return page;
461 }
462
463 /**
464 * __sgx_alloc_epc_page() - Allocate an EPC page
465 *
466 * Iterate through NUMA nodes and reserve ia free EPC page to the caller. Start
467 * from the NUMA node, where the caller is executing.
468 *
469 * Return:
470 * - an EPC page: A borrowed EPC pages were available.
471 * - NULL: Out of EPC pages.
472 */
__sgx_alloc_epc_page(void)473 struct sgx_epc_page *__sgx_alloc_epc_page(void)
474 {
475 struct sgx_epc_page *page;
476 int nid_of_current = numa_node_id();
477 int nid = nid_of_current;
478
479 if (node_isset(nid_of_current, sgx_numa_mask)) {
480 page = __sgx_alloc_epc_page_from_node(nid_of_current);
481 if (page)
482 return page;
483 }
484
485 /* Fall back to the non-local NUMA nodes: */
486 while (true) {
487 nid = next_node_in(nid, sgx_numa_mask);
488 if (nid == nid_of_current)
489 break;
490
491 page = __sgx_alloc_epc_page_from_node(nid);
492 if (page)
493 return page;
494 }
495
496 return ERR_PTR(-ENOMEM);
497 }
498
499 /**
500 * sgx_mark_page_reclaimable() - Mark a page as reclaimable
501 * @page: EPC page
502 *
503 * Mark a page as reclaimable and add it to the active page list. Pages
504 * are automatically removed from the active list when freed.
505 */
sgx_mark_page_reclaimable(struct sgx_epc_page * page)506 void sgx_mark_page_reclaimable(struct sgx_epc_page *page)
507 {
508 spin_lock(&sgx_reclaimer_lock);
509 page->flags |= SGX_EPC_PAGE_RECLAIMER_TRACKED;
510 list_add_tail(&page->list, &sgx_active_page_list);
511 spin_unlock(&sgx_reclaimer_lock);
512 }
513
514 /**
515 * sgx_unmark_page_reclaimable() - Remove a page from the reclaim list
516 * @page: EPC page
517 *
518 * Clear the reclaimable flag and remove the page from the active page list.
519 *
520 * Return:
521 * 0 on success,
522 * -EBUSY if the page is in the process of being reclaimed
523 */
sgx_unmark_page_reclaimable(struct sgx_epc_page * page)524 int sgx_unmark_page_reclaimable(struct sgx_epc_page *page)
525 {
526 spin_lock(&sgx_reclaimer_lock);
527 if (page->flags & SGX_EPC_PAGE_RECLAIMER_TRACKED) {
528 /* The page is being reclaimed. */
529 if (list_empty(&page->list)) {
530 spin_unlock(&sgx_reclaimer_lock);
531 return -EBUSY;
532 }
533
534 list_del(&page->list);
535 page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
536 }
537 spin_unlock(&sgx_reclaimer_lock);
538
539 return 0;
540 }
541
542 /**
543 * sgx_alloc_epc_page() - Allocate an EPC page
544 * @owner: the owner of the EPC page
545 * @reclaim: reclaim pages if necessary
546 *
547 * Iterate through EPC sections and borrow a free EPC page to the caller. When a
548 * page is no longer needed it must be released with sgx_free_epc_page(). If
549 * @reclaim is set to true, directly reclaim pages when we are out of pages. No
550 * mm's can be locked when @reclaim is set to true.
551 *
552 * Finally, wake up ksgxd when the number of pages goes below the watermark
553 * before returning back to the caller.
554 *
555 * Return:
556 * an EPC page,
557 * -errno on error
558 */
sgx_alloc_epc_page(void * owner,bool reclaim)559 struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim)
560 {
561 struct sgx_epc_page *page;
562
563 for ( ; ; ) {
564 page = __sgx_alloc_epc_page();
565 if (!IS_ERR(page)) {
566 page->owner = owner;
567 break;
568 }
569
570 if (list_empty(&sgx_active_page_list))
571 return ERR_PTR(-ENOMEM);
572
573 if (!reclaim) {
574 page = ERR_PTR(-EBUSY);
575 break;
576 }
577
578 if (signal_pending(current)) {
579 page = ERR_PTR(-ERESTARTSYS);
580 break;
581 }
582
583 sgx_reclaim_pages();
584 cond_resched();
585 }
586
587 if (sgx_should_reclaim(SGX_NR_LOW_PAGES))
588 wake_up(&ksgxd_waitq);
589
590 return page;
591 }
592
593 /**
594 * sgx_free_epc_page() - Free an EPC page
595 * @page: an EPC page
596 *
597 * Put the EPC page back to the list of free pages. It's the caller's
598 * responsibility to make sure that the page is in uninitialized state. In other
599 * words, do EREMOVE, EWB or whatever operation is necessary before calling
600 * this function.
601 */
sgx_free_epc_page(struct sgx_epc_page * page)602 void sgx_free_epc_page(struct sgx_epc_page *page)
603 {
604 struct sgx_epc_section *section = &sgx_epc_sections[page->section];
605 struct sgx_numa_node *node = section->node;
606
607 spin_lock(&node->lock);
608
609 page->owner = NULL;
610 if (page->poison)
611 list_add(&page->list, &node->sgx_poison_page_list);
612 else
613 list_add_tail(&page->list, &node->free_page_list);
614 page->flags = SGX_EPC_PAGE_IS_FREE;
615
616 spin_unlock(&node->lock);
617 atomic_long_inc(&sgx_nr_free_pages);
618 }
619
sgx_setup_epc_section(u64 phys_addr,u64 size,unsigned long index,struct sgx_epc_section * section)620 static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size,
621 unsigned long index,
622 struct sgx_epc_section *section)
623 {
624 unsigned long nr_pages = size >> PAGE_SHIFT;
625 unsigned long i;
626
627 section->virt_addr = memremap(phys_addr, size, MEMREMAP_WB);
628 if (!section->virt_addr)
629 return false;
630
631 section->pages = vmalloc(nr_pages * sizeof(struct sgx_epc_page));
632 if (!section->pages) {
633 memunmap(section->virt_addr);
634 return false;
635 }
636
637 section->phys_addr = phys_addr;
638 xa_store_range(&sgx_epc_address_space, section->phys_addr,
639 phys_addr + size - 1, section, GFP_KERNEL);
640
641 for (i = 0; i < nr_pages; i++) {
642 section->pages[i].section = index;
643 section->pages[i].flags = 0;
644 section->pages[i].owner = NULL;
645 section->pages[i].poison = 0;
646 list_add_tail(§ion->pages[i].list, &sgx_dirty_page_list);
647 }
648
649 return true;
650 }
651
arch_is_platform_page(u64 paddr)652 bool arch_is_platform_page(u64 paddr)
653 {
654 return !!xa_load(&sgx_epc_address_space, paddr);
655 }
656 EXPORT_SYMBOL_GPL(arch_is_platform_page);
657
sgx_paddr_to_page(u64 paddr)658 static struct sgx_epc_page *sgx_paddr_to_page(u64 paddr)
659 {
660 struct sgx_epc_section *section;
661
662 section = xa_load(&sgx_epc_address_space, paddr);
663 if (!section)
664 return NULL;
665
666 return §ion->pages[PFN_DOWN(paddr - section->phys_addr)];
667 }
668
669 /*
670 * Called in process context to handle a hardware reported
671 * error in an SGX EPC page.
672 * If the MF_ACTION_REQUIRED bit is set in flags, then the
673 * context is the task that consumed the poison data. Otherwise
674 * this is called from a kernel thread unrelated to the page.
675 */
arch_memory_failure(unsigned long pfn,int flags)676 int arch_memory_failure(unsigned long pfn, int flags)
677 {
678 struct sgx_epc_page *page = sgx_paddr_to_page(pfn << PAGE_SHIFT);
679 struct sgx_epc_section *section;
680 struct sgx_numa_node *node;
681
682 /*
683 * mm/memory-failure.c calls this routine for all errors
684 * where there isn't a "struct page" for the address. But that
685 * includes other address ranges besides SGX.
686 */
687 if (!page)
688 return -ENXIO;
689
690 /*
691 * If poison was consumed synchronously. Send a SIGBUS to
692 * the task. Hardware has already exited the SGX enclave and
693 * will not allow re-entry to an enclave that has a memory
694 * error. The signal may help the task understand why the
695 * enclave is broken.
696 */
697 if (flags & MF_ACTION_REQUIRED)
698 force_sig(SIGBUS);
699
700 section = &sgx_epc_sections[page->section];
701 node = section->node;
702
703 spin_lock(&node->lock);
704
705 /* Already poisoned? Nothing more to do */
706 if (page->poison)
707 goto out;
708
709 page->poison = 1;
710
711 /*
712 * If the page is on a free list, move it to the per-node
713 * poison page list.
714 */
715 if (page->flags & SGX_EPC_PAGE_IS_FREE) {
716 list_move(&page->list, &node->sgx_poison_page_list);
717 goto out;
718 }
719
720 /*
721 * TBD: Add additional plumbing to enable pre-emptive
722 * action for asynchronous poison notification. Until
723 * then just hope that the poison:
724 * a) is not accessed - sgx_free_epc_page() will deal with it
725 * when the user gives it back
726 * b) results in a recoverable machine check rather than
727 * a fatal one
728 */
729 out:
730 spin_unlock(&node->lock);
731 return 0;
732 }
733
734 /**
735 * A section metric is concatenated in a way that @low bits 12-31 define the
736 * bits 12-31 of the metric and @high bits 0-19 define the bits 32-51 of the
737 * metric.
738 */
sgx_calc_section_metric(u64 low,u64 high)739 static inline u64 __init sgx_calc_section_metric(u64 low, u64 high)
740 {
741 return (low & GENMASK_ULL(31, 12)) +
742 ((high & GENMASK_ULL(19, 0)) << 32);
743 }
744
745 #ifdef CONFIG_NUMA
sgx_total_bytes_show(struct device * dev,struct device_attribute * attr,char * buf)746 static ssize_t sgx_total_bytes_show(struct device *dev, struct device_attribute *attr, char *buf)
747 {
748 return sysfs_emit(buf, "%lu\n", sgx_numa_nodes[dev->id].size);
749 }
750 static DEVICE_ATTR_RO(sgx_total_bytes);
751
arch_node_attr_is_visible(struct kobject * kobj,struct attribute * attr,int idx)752 static umode_t arch_node_attr_is_visible(struct kobject *kobj,
753 struct attribute *attr, int idx)
754 {
755 /* Make all x86/ attributes invisible when SGX is not initialized: */
756 if (nodes_empty(sgx_numa_mask))
757 return 0;
758
759 return attr->mode;
760 }
761
762 static struct attribute *arch_node_dev_attrs[] = {
763 &dev_attr_sgx_total_bytes.attr,
764 NULL,
765 };
766
767 const struct attribute_group arch_node_dev_group = {
768 .name = "x86",
769 .attrs = arch_node_dev_attrs,
770 .is_visible = arch_node_attr_is_visible,
771 };
772
arch_update_sysfs_visibility(int nid)773 static void __init arch_update_sysfs_visibility(int nid)
774 {
775 struct node *node = node_devices[nid];
776 int ret;
777
778 ret = sysfs_update_group(&node->dev.kobj, &arch_node_dev_group);
779
780 if (ret)
781 pr_err("sysfs update failed (%d), files may be invisible", ret);
782 }
783 #else /* !CONFIG_NUMA */
arch_update_sysfs_visibility(int nid)784 static void __init arch_update_sysfs_visibility(int nid) {}
785 #endif
786
sgx_page_cache_init(void)787 static bool __init sgx_page_cache_init(void)
788 {
789 u32 eax, ebx, ecx, edx, type;
790 u64 pa, size;
791 int nid;
792 int i;
793
794 sgx_numa_nodes = kmalloc_array(num_possible_nodes(), sizeof(*sgx_numa_nodes), GFP_KERNEL);
795 if (!sgx_numa_nodes)
796 return false;
797
798 for (i = 0; i < ARRAY_SIZE(sgx_epc_sections); i++) {
799 cpuid_count(SGX_CPUID, i + SGX_CPUID_EPC, &eax, &ebx, &ecx, &edx);
800
801 type = eax & SGX_CPUID_EPC_MASK;
802 if (type == SGX_CPUID_EPC_INVALID)
803 break;
804
805 if (type != SGX_CPUID_EPC_SECTION) {
806 pr_err_once("Unknown EPC section type: %u\n", type);
807 break;
808 }
809
810 pa = sgx_calc_section_metric(eax, ebx);
811 size = sgx_calc_section_metric(ecx, edx);
812
813 pr_info("EPC section 0x%llx-0x%llx\n", pa, pa + size - 1);
814
815 if (!sgx_setup_epc_section(pa, size, i, &sgx_epc_sections[i])) {
816 pr_err("No free memory for an EPC section\n");
817 break;
818 }
819
820 nid = numa_map_to_online_node(phys_to_target_node(pa));
821 if (nid == NUMA_NO_NODE) {
822 /* The physical address is already printed above. */
823 pr_warn(FW_BUG "Unable to map EPC section to online node. Fallback to the NUMA node 0.\n");
824 nid = 0;
825 }
826
827 if (!node_isset(nid, sgx_numa_mask)) {
828 spin_lock_init(&sgx_numa_nodes[nid].lock);
829 INIT_LIST_HEAD(&sgx_numa_nodes[nid].free_page_list);
830 INIT_LIST_HEAD(&sgx_numa_nodes[nid].sgx_poison_page_list);
831 node_set(nid, sgx_numa_mask);
832 sgx_numa_nodes[nid].size = 0;
833
834 /* Make SGX-specific node sysfs files visible: */
835 arch_update_sysfs_visibility(nid);
836 }
837
838 sgx_epc_sections[i].node = &sgx_numa_nodes[nid];
839 sgx_numa_nodes[nid].size += size;
840
841 sgx_nr_epc_sections++;
842 }
843
844 if (!sgx_nr_epc_sections) {
845 pr_err("There are zero EPC sections.\n");
846 return false;
847 }
848
849 return true;
850 }
851
852 /*
853 * Update the SGX_LEPUBKEYHASH MSRs to the values specified by caller.
854 * Bare-metal driver requires to update them to hash of enclave's signer
855 * before EINIT. KVM needs to update them to guest's virtual MSR values
856 * before doing EINIT from guest.
857 */
sgx_update_lepubkeyhash(u64 * lepubkeyhash)858 void sgx_update_lepubkeyhash(u64 *lepubkeyhash)
859 {
860 int i;
861
862 WARN_ON_ONCE(preemptible());
863
864 for (i = 0; i < 4; i++)
865 wrmsrl(MSR_IA32_SGXLEPUBKEYHASH0 + i, lepubkeyhash[i]);
866 }
867
868 const struct file_operations sgx_provision_fops = {
869 .owner = THIS_MODULE,
870 };
871
872 static struct miscdevice sgx_dev_provision = {
873 .minor = MISC_DYNAMIC_MINOR,
874 .name = "sgx_provision",
875 .nodename = "sgx_provision",
876 .fops = &sgx_provision_fops,
877 };
878
879 /**
880 * sgx_set_attribute() - Update allowed attributes given file descriptor
881 * @allowed_attributes: Pointer to allowed enclave attributes
882 * @attribute_fd: File descriptor for specific attribute
883 *
884 * Append enclave attribute indicated by file descriptor to allowed
885 * attributes. Currently only SGX_ATTR_PROVISIONKEY indicated by
886 * /dev/sgx_provision is supported.
887 *
888 * Return:
889 * -0: SGX_ATTR_PROVISIONKEY is appended to allowed_attributes
890 * -EINVAL: Invalid, or not supported file descriptor
891 */
sgx_set_attribute(unsigned long * allowed_attributes,unsigned int attribute_fd)892 int sgx_set_attribute(unsigned long *allowed_attributes,
893 unsigned int attribute_fd)
894 {
895 struct file *file;
896
897 file = fget(attribute_fd);
898 if (!file)
899 return -EINVAL;
900
901 if (file->f_op != &sgx_provision_fops) {
902 fput(file);
903 return -EINVAL;
904 }
905
906 *allowed_attributes |= SGX_ATTR_PROVISIONKEY;
907
908 fput(file);
909 return 0;
910 }
911 EXPORT_SYMBOL_GPL(sgx_set_attribute);
912
sgx_init(void)913 static int __init sgx_init(void)
914 {
915 int ret;
916 int i;
917
918 if (!cpu_feature_enabled(X86_FEATURE_SGX))
919 return -ENODEV;
920
921 if (!sgx_page_cache_init())
922 return -ENOMEM;
923
924 if (!sgx_page_reclaimer_init()) {
925 ret = -ENOMEM;
926 goto err_page_cache;
927 }
928
929 ret = misc_register(&sgx_dev_provision);
930 if (ret)
931 goto err_kthread;
932
933 /*
934 * Always try to initialize the native *and* KVM drivers.
935 * The KVM driver is less picky than the native one and
936 * can function if the native one is not supported on the
937 * current system or fails to initialize.
938 *
939 * Error out only if both fail to initialize.
940 */
941 ret = sgx_drv_init();
942
943 if (sgx_vepc_init() && ret)
944 goto err_provision;
945
946 return 0;
947
948 err_provision:
949 misc_deregister(&sgx_dev_provision);
950
951 err_kthread:
952 kthread_stop(ksgxd_tsk);
953
954 err_page_cache:
955 for (i = 0; i < sgx_nr_epc_sections; i++) {
956 vfree(sgx_epc_sections[i].pages);
957 memunmap(sgx_epc_sections[i].virt_addr);
958 }
959
960 return ret;
961 }
962
963 device_initcall(sgx_init);
964