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Linux/arch/x86/xen/setup.c

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /*
  3  * Machine specific setup for xen
  4  *
  5  * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
  6  */
  7 
  8 #include <linux/init.h>
  9 #include <linux/sched.h>
 10 #include <linux/mm.h>
 11 #include <linux/pm.h>
 12 #include <linux/memblock.h>
 13 #include <linux/cpuidle.h>
 14 #include <linux/cpufreq.h>
 15 
 16 #include <asm/elf.h>
 17 #include <asm/vdso.h>
 18 #include <asm/e820/api.h>
 19 #include <asm/setup.h>
 20 #include <asm/acpi.h>
 21 #include <asm/numa.h>
 22 #include <asm/xen/hypervisor.h>
 23 #include <asm/xen/hypercall.h>
 24 
 25 #include <xen/xen.h>
 26 #include <xen/page.h>
 27 #include <xen/interface/callback.h>
 28 #include <xen/interface/memory.h>
 29 #include <xen/interface/physdev.h>
 30 #include <xen/features.h>
 31 #include <xen/hvc-console.h>
 32 #include "xen-ops.h"
 33 #include "vdso.h"
 34 #include "mmu.h"
 35 
 36 #define GB(x) ((uint64_t)(x) * 1024 * 1024 * 1024)
 37 
 38 /* Amount of extra memory space we add to the e820 ranges */
 39 struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;
 40 
 41 /* Number of pages released from the initial allocation. */
 42 unsigned long xen_released_pages;
 43 
 44 /* E820 map used during setting up memory. */
 45 static struct e820_table xen_e820_table __initdata;
 46 
 47 /*
 48  * Buffer used to remap identity mapped pages. We only need the virtual space.
 49  * The physical page behind this address is remapped as needed to different
 50  * buffer pages.
 51  */
 52 #define REMAP_SIZE      (P2M_PER_PAGE - 3)
 53 static struct {
 54         unsigned long   next_area_mfn;
 55         unsigned long   target_pfn;
 56         unsigned long   size;
 57         unsigned long   mfns[REMAP_SIZE];
 58 } xen_remap_buf __initdata __aligned(PAGE_SIZE);
 59 static unsigned long xen_remap_mfn __initdata = INVALID_P2M_ENTRY;
 60 
 61 /* 
 62  * The maximum amount of extra memory compared to the base size.  The
 63  * main scaling factor is the size of struct page.  At extreme ratios
 64  * of base:extra, all the base memory can be filled with page
 65  * structures for the extra memory, leaving no space for anything
 66  * else.
 67  * 
 68  * 10x seems like a reasonable balance between scaling flexibility and
 69  * leaving a practically usable system.
 70  */
 71 #define EXTRA_MEM_RATIO         (10)
 72 
 73 static bool xen_512gb_limit __initdata = IS_ENABLED(CONFIG_XEN_512GB);
 74 
 75 static void __init xen_parse_512gb(void)
 76 {
 77         bool val = false;
 78         char *arg;
 79 
 80         arg = strstr(xen_start_info->cmd_line, "xen_512gb_limit");
 81         if (!arg)
 82                 return;
 83 
 84         arg = strstr(xen_start_info->cmd_line, "xen_512gb_limit=");
 85         if (!arg)
 86                 val = true;
 87         else if (strtobool(arg + strlen("xen_512gb_limit="), &val))
 88                 return;
 89 
 90         xen_512gb_limit = val;
 91 }
 92 
 93 static void __init xen_add_extra_mem(unsigned long start_pfn,
 94                                      unsigned long n_pfns)
 95 {
 96         int i;
 97 
 98         /*
 99          * No need to check for zero size, should happen rarely and will only
100          * write a new entry regarded to be unused due to zero size.
101          */
102         for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
103                 /* Add new region. */
104                 if (xen_extra_mem[i].n_pfns == 0) {
105                         xen_extra_mem[i].start_pfn = start_pfn;
106                         xen_extra_mem[i].n_pfns = n_pfns;
107                         break;
108                 }
109                 /* Append to existing region. */
110                 if (xen_extra_mem[i].start_pfn + xen_extra_mem[i].n_pfns ==
111                     start_pfn) {
112                         xen_extra_mem[i].n_pfns += n_pfns;
113                         break;
114                 }
115         }
116         if (i == XEN_EXTRA_MEM_MAX_REGIONS)
117                 printk(KERN_WARNING "Warning: not enough extra memory regions\n");
118 
119         memblock_reserve(PFN_PHYS(start_pfn), PFN_PHYS(n_pfns));
120 }
121 
122 static void __init xen_del_extra_mem(unsigned long start_pfn,
123                                      unsigned long n_pfns)
124 {
125         int i;
126         unsigned long start_r, size_r;
127 
128         for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
129                 start_r = xen_extra_mem[i].start_pfn;
130                 size_r = xen_extra_mem[i].n_pfns;
131 
132                 /* Start of region. */
133                 if (start_r == start_pfn) {
134                         BUG_ON(n_pfns > size_r);
135                         xen_extra_mem[i].start_pfn += n_pfns;
136                         xen_extra_mem[i].n_pfns -= n_pfns;
137                         break;
138                 }
139                 /* End of region. */
140                 if (start_r + size_r == start_pfn + n_pfns) {
141                         BUG_ON(n_pfns > size_r);
142                         xen_extra_mem[i].n_pfns -= n_pfns;
143                         break;
144                 }
145                 /* Mid of region. */
146                 if (start_pfn > start_r && start_pfn < start_r + size_r) {
147                         BUG_ON(start_pfn + n_pfns > start_r + size_r);
148                         xen_extra_mem[i].n_pfns = start_pfn - start_r;
149                         /* Calling memblock_reserve() again is okay. */
150                         xen_add_extra_mem(start_pfn + n_pfns, start_r + size_r -
151                                           (start_pfn + n_pfns));
152                         break;
153                 }
154         }
155         memblock_free(PFN_PHYS(start_pfn), PFN_PHYS(n_pfns));
156 }
157 
158 /*
159  * Called during boot before the p2m list can take entries beyond the
160  * hypervisor supplied p2m list. Entries in extra mem are to be regarded as
161  * invalid.
162  */
163 unsigned long __ref xen_chk_extra_mem(unsigned long pfn)
164 {
165         int i;
166 
167         for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
168                 if (pfn >= xen_extra_mem[i].start_pfn &&
169                     pfn < xen_extra_mem[i].start_pfn + xen_extra_mem[i].n_pfns)
170                         return INVALID_P2M_ENTRY;
171         }
172 
173         return IDENTITY_FRAME(pfn);
174 }
175 
176 /*
177  * Mark all pfns of extra mem as invalid in p2m list.
178  */
179 void __init xen_inv_extra_mem(void)
180 {
181         unsigned long pfn, pfn_s, pfn_e;
182         int i;
183 
184         for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
185                 if (!xen_extra_mem[i].n_pfns)
186                         continue;
187                 pfn_s = xen_extra_mem[i].start_pfn;
188                 pfn_e = pfn_s + xen_extra_mem[i].n_pfns;
189                 for (pfn = pfn_s; pfn < pfn_e; pfn++)
190                         set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
191         }
192 }
193 
194 /*
195  * Finds the next RAM pfn available in the E820 map after min_pfn.
196  * This function updates min_pfn with the pfn found and returns
197  * the size of that range or zero if not found.
198  */
199 static unsigned long __init xen_find_pfn_range(unsigned long *min_pfn)
200 {
201         const struct e820_entry *entry = xen_e820_table.entries;
202         unsigned int i;
203         unsigned long done = 0;
204 
205         for (i = 0; i < xen_e820_table.nr_entries; i++, entry++) {
206                 unsigned long s_pfn;
207                 unsigned long e_pfn;
208 
209                 if (entry->type != E820_TYPE_RAM)
210                         continue;
211 
212                 e_pfn = PFN_DOWN(entry->addr + entry->size);
213 
214                 /* We only care about E820 after this */
215                 if (e_pfn <= *min_pfn)
216                         continue;
217 
218                 s_pfn = PFN_UP(entry->addr);
219 
220                 /* If min_pfn falls within the E820 entry, we want to start
221                  * at the min_pfn PFN.
222                  */
223                 if (s_pfn <= *min_pfn) {
224                         done = e_pfn - *min_pfn;
225                 } else {
226                         done = e_pfn - s_pfn;
227                         *min_pfn = s_pfn;
228                 }
229                 break;
230         }
231 
232         return done;
233 }
234 
235 static int __init xen_free_mfn(unsigned long mfn)
236 {
237         struct xen_memory_reservation reservation = {
238                 .address_bits = 0,
239                 .extent_order = 0,
240                 .domid        = DOMID_SELF
241         };
242 
243         set_xen_guest_handle(reservation.extent_start, &mfn);
244         reservation.nr_extents = 1;
245 
246         return HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation);
247 }
248 
249 /*
250  * This releases a chunk of memory and then does the identity map. It's used
251  * as a fallback if the remapping fails.
252  */
253 static void __init xen_set_identity_and_release_chunk(unsigned long start_pfn,
254                         unsigned long end_pfn, unsigned long nr_pages)
255 {
256         unsigned long pfn, end;
257         int ret;
258 
259         WARN_ON(start_pfn > end_pfn);
260 
261         /* Release pages first. */
262         end = min(end_pfn, nr_pages);
263         for (pfn = start_pfn; pfn < end; pfn++) {
264                 unsigned long mfn = pfn_to_mfn(pfn);
265 
266                 /* Make sure pfn exists to start with */
267                 if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn)
268                         continue;
269 
270                 ret = xen_free_mfn(mfn);
271                 WARN(ret != 1, "Failed to release pfn %lx err=%d\n", pfn, ret);
272 
273                 if (ret == 1) {
274                         xen_released_pages++;
275                         if (!__set_phys_to_machine(pfn, INVALID_P2M_ENTRY))
276                                 break;
277                 } else
278                         break;
279         }
280 
281         set_phys_range_identity(start_pfn, end_pfn);
282 }
283 
284 /*
285  * Helper function to update the p2m and m2p tables and kernel mapping.
286  */
287 static void __init xen_update_mem_tables(unsigned long pfn, unsigned long mfn)
288 {
289         struct mmu_update update = {
290                 .ptr = ((uint64_t)mfn << PAGE_SHIFT) | MMU_MACHPHYS_UPDATE,
291                 .val = pfn
292         };
293 
294         /* Update p2m */
295         if (!set_phys_to_machine(pfn, mfn)) {
296                 WARN(1, "Failed to set p2m mapping for pfn=%ld mfn=%ld\n",
297                      pfn, mfn);
298                 BUG();
299         }
300 
301         /* Update m2p */
302         if (HYPERVISOR_mmu_update(&update, 1, NULL, DOMID_SELF) < 0) {
303                 WARN(1, "Failed to set m2p mapping for mfn=%ld pfn=%ld\n",
304                      mfn, pfn);
305                 BUG();
306         }
307 
308         /* Update kernel mapping, but not for highmem. */
309         if (pfn >= PFN_UP(__pa(high_memory - 1)))
310                 return;
311 
312         if (HYPERVISOR_update_va_mapping((unsigned long)__va(pfn << PAGE_SHIFT),
313                                          mfn_pte(mfn, PAGE_KERNEL), 0)) {
314                 WARN(1, "Failed to update kernel mapping for mfn=%ld pfn=%ld\n",
315                       mfn, pfn);
316                 BUG();
317         }
318 }
319 
320 /*
321  * This function updates the p2m and m2p tables with an identity map from
322  * start_pfn to start_pfn+size and prepares remapping the underlying RAM of the
323  * original allocation at remap_pfn. The information needed for remapping is
324  * saved in the memory itself to avoid the need for allocating buffers. The
325  * complete remap information is contained in a list of MFNs each containing
326  * up to REMAP_SIZE MFNs and the start target PFN for doing the remap.
327  * This enables us to preserve the original mfn sequence while doing the
328  * remapping at a time when the memory management is capable of allocating
329  * virtual and physical memory in arbitrary amounts, see 'xen_remap_memory' and
330  * its callers.
331  */
332 static void __init xen_do_set_identity_and_remap_chunk(
333         unsigned long start_pfn, unsigned long size, unsigned long remap_pfn)
334 {
335         unsigned long buf = (unsigned long)&xen_remap_buf;
336         unsigned long mfn_save, mfn;
337         unsigned long ident_pfn_iter, remap_pfn_iter;
338         unsigned long ident_end_pfn = start_pfn + size;
339         unsigned long left = size;
340         unsigned int i, chunk;
341 
342         WARN_ON(size == 0);
343 
344         mfn_save = virt_to_mfn(buf);
345 
346         for (ident_pfn_iter = start_pfn, remap_pfn_iter = remap_pfn;
347              ident_pfn_iter < ident_end_pfn;
348              ident_pfn_iter += REMAP_SIZE, remap_pfn_iter += REMAP_SIZE) {
349                 chunk = (left < REMAP_SIZE) ? left : REMAP_SIZE;
350 
351                 /* Map first pfn to xen_remap_buf */
352                 mfn = pfn_to_mfn(ident_pfn_iter);
353                 set_pte_mfn(buf, mfn, PAGE_KERNEL);
354 
355                 /* Save mapping information in page */
356                 xen_remap_buf.next_area_mfn = xen_remap_mfn;
357                 xen_remap_buf.target_pfn = remap_pfn_iter;
358                 xen_remap_buf.size = chunk;
359                 for (i = 0; i < chunk; i++)
360                         xen_remap_buf.mfns[i] = pfn_to_mfn(ident_pfn_iter + i);
361 
362                 /* Put remap buf into list. */
363                 xen_remap_mfn = mfn;
364 
365                 /* Set identity map */
366                 set_phys_range_identity(ident_pfn_iter, ident_pfn_iter + chunk);
367 
368                 left -= chunk;
369         }
370 
371         /* Restore old xen_remap_buf mapping */
372         set_pte_mfn(buf, mfn_save, PAGE_KERNEL);
373 }
374 
375 /*
376  * This function takes a contiguous pfn range that needs to be identity mapped
377  * and:
378  *
379  *  1) Finds a new range of pfns to use to remap based on E820 and remap_pfn.
380  *  2) Calls the do_ function to actually do the mapping/remapping work.
381  *
382  * The goal is to not allocate additional memory but to remap the existing
383  * pages. In the case of an error the underlying memory is simply released back
384  * to Xen and not remapped.
385  */
386 static unsigned long __init xen_set_identity_and_remap_chunk(
387         unsigned long start_pfn, unsigned long end_pfn, unsigned long nr_pages,
388         unsigned long remap_pfn)
389 {
390         unsigned long pfn;
391         unsigned long i = 0;
392         unsigned long n = end_pfn - start_pfn;
393 
394         if (remap_pfn == 0)
395                 remap_pfn = nr_pages;
396 
397         while (i < n) {
398                 unsigned long cur_pfn = start_pfn + i;
399                 unsigned long left = n - i;
400                 unsigned long size = left;
401                 unsigned long remap_range_size;
402 
403                 /* Do not remap pages beyond the current allocation */
404                 if (cur_pfn >= nr_pages) {
405                         /* Identity map remaining pages */
406                         set_phys_range_identity(cur_pfn, cur_pfn + size);
407                         break;
408                 }
409                 if (cur_pfn + size > nr_pages)
410                         size = nr_pages - cur_pfn;
411 
412                 remap_range_size = xen_find_pfn_range(&remap_pfn);
413                 if (!remap_range_size) {
414                         pr_warning("Unable to find available pfn range, not remapping identity pages\n");
415                         xen_set_identity_and_release_chunk(cur_pfn,
416                                                 cur_pfn + left, nr_pages);
417                         break;
418                 }
419                 /* Adjust size to fit in current e820 RAM region */
420                 if (size > remap_range_size)
421                         size = remap_range_size;
422 
423                 xen_do_set_identity_and_remap_chunk(cur_pfn, size, remap_pfn);
424 
425                 /* Update variables to reflect new mappings. */
426                 i += size;
427                 remap_pfn += size;
428         }
429 
430         /*
431          * If the PFNs are currently mapped, the VA mapping also needs
432          * to be updated to be 1:1.
433          */
434         for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++)
435                 (void)HYPERVISOR_update_va_mapping(
436                         (unsigned long)__va(pfn << PAGE_SHIFT),
437                         mfn_pte(pfn, PAGE_KERNEL_IO), 0);
438 
439         return remap_pfn;
440 }
441 
442 static unsigned long __init xen_count_remap_pages(
443         unsigned long start_pfn, unsigned long end_pfn, unsigned long nr_pages,
444         unsigned long remap_pages)
445 {
446         if (start_pfn >= nr_pages)
447                 return remap_pages;
448 
449         return remap_pages + min(end_pfn, nr_pages) - start_pfn;
450 }
451 
452 static unsigned long __init xen_foreach_remap_area(unsigned long nr_pages,
453         unsigned long (*func)(unsigned long start_pfn, unsigned long end_pfn,
454                               unsigned long nr_pages, unsigned long last_val))
455 {
456         phys_addr_t start = 0;
457         unsigned long ret_val = 0;
458         const struct e820_entry *entry = xen_e820_table.entries;
459         int i;
460 
461         /*
462          * Combine non-RAM regions and gaps until a RAM region (or the
463          * end of the map) is reached, then call the provided function
464          * to perform its duty on the non-RAM region.
465          *
466          * The combined non-RAM regions are rounded to a whole number
467          * of pages so any partial pages are accessible via the 1:1
468          * mapping.  This is needed for some BIOSes that put (for
469          * example) the DMI tables in a reserved region that begins on
470          * a non-page boundary.
471          */
472         for (i = 0; i < xen_e820_table.nr_entries; i++, entry++) {
473                 phys_addr_t end = entry->addr + entry->size;
474                 if (entry->type == E820_TYPE_RAM || i == xen_e820_table.nr_entries - 1) {
475                         unsigned long start_pfn = PFN_DOWN(start);
476                         unsigned long end_pfn = PFN_UP(end);
477 
478                         if (entry->type == E820_TYPE_RAM)
479                                 end_pfn = PFN_UP(entry->addr);
480 
481                         if (start_pfn < end_pfn)
482                                 ret_val = func(start_pfn, end_pfn, nr_pages,
483                                                ret_val);
484                         start = end;
485                 }
486         }
487 
488         return ret_val;
489 }
490 
491 /*
492  * Remap the memory prepared in xen_do_set_identity_and_remap_chunk().
493  * The remap information (which mfn remap to which pfn) is contained in the
494  * to be remapped memory itself in a linked list anchored at xen_remap_mfn.
495  * This scheme allows to remap the different chunks in arbitrary order while
496  * the resulting mapping will be independant from the order.
497  */
498 void __init xen_remap_memory(void)
499 {
500         unsigned long buf = (unsigned long)&xen_remap_buf;
501         unsigned long mfn_save, pfn;
502         unsigned long remapped = 0;
503         unsigned int i;
504         unsigned long pfn_s = ~0UL;
505         unsigned long len = 0;
506 
507         mfn_save = virt_to_mfn(buf);
508 
509         while (xen_remap_mfn != INVALID_P2M_ENTRY) {
510                 /* Map the remap information */
511                 set_pte_mfn(buf, xen_remap_mfn, PAGE_KERNEL);
512 
513                 BUG_ON(xen_remap_mfn != xen_remap_buf.mfns[0]);
514 
515                 pfn = xen_remap_buf.target_pfn;
516                 for (i = 0; i < xen_remap_buf.size; i++) {
517                         xen_update_mem_tables(pfn, xen_remap_buf.mfns[i]);
518                         remapped++;
519                         pfn++;
520                 }
521                 if (pfn_s == ~0UL || pfn == pfn_s) {
522                         pfn_s = xen_remap_buf.target_pfn;
523                         len += xen_remap_buf.size;
524                 } else if (pfn_s + len == xen_remap_buf.target_pfn) {
525                         len += xen_remap_buf.size;
526                 } else {
527                         xen_del_extra_mem(pfn_s, len);
528                         pfn_s = xen_remap_buf.target_pfn;
529                         len = xen_remap_buf.size;
530                 }
531                 xen_remap_mfn = xen_remap_buf.next_area_mfn;
532         }
533 
534         if (pfn_s != ~0UL && len)
535                 xen_del_extra_mem(pfn_s, len);
536 
537         set_pte_mfn(buf, mfn_save, PAGE_KERNEL);
538 
539         pr_info("Remapped %ld page(s)\n", remapped);
540 }
541 
542 static unsigned long __init xen_get_pages_limit(void)
543 {
544         unsigned long limit;
545 
546 #ifdef CONFIG_X86_32
547         limit = GB(64) / PAGE_SIZE;
548 #else
549         limit = MAXMEM / PAGE_SIZE;
550         if (!xen_initial_domain() && xen_512gb_limit)
551                 limit = GB(512) / PAGE_SIZE;
552 #endif
553         return limit;
554 }
555 
556 static unsigned long __init xen_get_max_pages(void)
557 {
558         unsigned long max_pages, limit;
559         domid_t domid = DOMID_SELF;
560         long ret;
561 
562         limit = xen_get_pages_limit();
563         max_pages = limit;
564 
565         /*
566          * For the initial domain we use the maximum reservation as
567          * the maximum page.
568          *
569          * For guest domains the current maximum reservation reflects
570          * the current maximum rather than the static maximum. In this
571          * case the e820 map provided to us will cover the static
572          * maximum region.
573          */
574         if (xen_initial_domain()) {
575                 ret = HYPERVISOR_memory_op(XENMEM_maximum_reservation, &domid);
576                 if (ret > 0)
577                         max_pages = ret;
578         }
579 
580         return min(max_pages, limit);
581 }
582 
583 static void __init xen_align_and_add_e820_region(phys_addr_t start,
584                                                  phys_addr_t size, int type)
585 {
586         phys_addr_t end = start + size;
587 
588         /* Align RAM regions to page boundaries. */
589         if (type == E820_TYPE_RAM) {
590                 start = PAGE_ALIGN(start);
591                 end &= ~((phys_addr_t)PAGE_SIZE - 1);
592         }
593 
594         e820__range_add(start, end - start, type);
595 }
596 
597 static void __init xen_ignore_unusable(void)
598 {
599         struct e820_entry *entry = xen_e820_table.entries;
600         unsigned int i;
601 
602         for (i = 0; i < xen_e820_table.nr_entries; i++, entry++) {
603                 if (entry->type == E820_TYPE_UNUSABLE)
604                         entry->type = E820_TYPE_RAM;
605         }
606 }
607 
608 bool __init xen_is_e820_reserved(phys_addr_t start, phys_addr_t size)
609 {
610         struct e820_entry *entry;
611         unsigned mapcnt;
612         phys_addr_t end;
613 
614         if (!size)
615                 return false;
616 
617         end = start + size;
618         entry = xen_e820_table.entries;
619 
620         for (mapcnt = 0; mapcnt < xen_e820_table.nr_entries; mapcnt++) {
621                 if (entry->type == E820_TYPE_RAM && entry->addr <= start &&
622                     (entry->addr + entry->size) >= end)
623                         return false;
624 
625                 entry++;
626         }
627 
628         return true;
629 }
630 
631 /*
632  * Find a free area in physical memory not yet reserved and compliant with
633  * E820 map.
634  * Used to relocate pre-allocated areas like initrd or p2m list which are in
635  * conflict with the to be used E820 map.
636  * In case no area is found, return 0. Otherwise return the physical address
637  * of the area which is already reserved for convenience.
638  */
639 phys_addr_t __init xen_find_free_area(phys_addr_t size)
640 {
641         unsigned mapcnt;
642         phys_addr_t addr, start;
643         struct e820_entry *entry = xen_e820_table.entries;
644 
645         for (mapcnt = 0; mapcnt < xen_e820_table.nr_entries; mapcnt++, entry++) {
646                 if (entry->type != E820_TYPE_RAM || entry->size < size)
647                         continue;
648                 start = entry->addr;
649                 for (addr = start; addr < start + size; addr += PAGE_SIZE) {
650                         if (!memblock_is_reserved(addr))
651                                 continue;
652                         start = addr + PAGE_SIZE;
653                         if (start + size > entry->addr + entry->size)
654                                 break;
655                 }
656                 if (addr >= start + size) {
657                         memblock_reserve(start, size);
658                         return start;
659                 }
660         }
661 
662         return 0;
663 }
664 
665 /*
666  * Like memcpy, but with physical addresses for dest and src.
667  */
668 static void __init xen_phys_memcpy(phys_addr_t dest, phys_addr_t src,
669                                    phys_addr_t n)
670 {
671         phys_addr_t dest_off, src_off, dest_len, src_len, len;
672         void *from, *to;
673 
674         while (n) {
675                 dest_off = dest & ~PAGE_MASK;
676                 src_off = src & ~PAGE_MASK;
677                 dest_len = n;
678                 if (dest_len > (NR_FIX_BTMAPS << PAGE_SHIFT) - dest_off)
679                         dest_len = (NR_FIX_BTMAPS << PAGE_SHIFT) - dest_off;
680                 src_len = n;
681                 if (src_len > (NR_FIX_BTMAPS << PAGE_SHIFT) - src_off)
682                         src_len = (NR_FIX_BTMAPS << PAGE_SHIFT) - src_off;
683                 len = min(dest_len, src_len);
684                 to = early_memremap(dest - dest_off, dest_len + dest_off);
685                 from = early_memremap(src - src_off, src_len + src_off);
686                 memcpy(to, from, len);
687                 early_memunmap(to, dest_len + dest_off);
688                 early_memunmap(from, src_len + src_off);
689                 n -= len;
690                 dest += len;
691                 src += len;
692         }
693 }
694 
695 /*
696  * Reserve Xen mfn_list.
697  */
698 static void __init xen_reserve_xen_mfnlist(void)
699 {
700         phys_addr_t start, size;
701 
702         if (xen_start_info->mfn_list >= __START_KERNEL_map) {
703                 start = __pa(xen_start_info->mfn_list);
704                 size = PFN_ALIGN(xen_start_info->nr_pages *
705                                  sizeof(unsigned long));
706         } else {
707                 start = PFN_PHYS(xen_start_info->first_p2m_pfn);
708                 size = PFN_PHYS(xen_start_info->nr_p2m_frames);
709         }
710 
711         memblock_reserve(start, size);
712         if (!xen_is_e820_reserved(start, size))
713                 return;
714 
715 #ifdef CONFIG_X86_32
716         /*
717          * Relocating the p2m on 32 bit system to an arbitrary virtual address
718          * is not supported, so just give up.
719          */
720         xen_raw_console_write("Xen hypervisor allocated p2m list conflicts with E820 map\n");
721         BUG();
722 #else
723         xen_relocate_p2m();
724         memblock_free(start, size);
725 #endif
726 }
727 
728 /**
729  * machine_specific_memory_setup - Hook for machine specific memory setup.
730  **/
731 char * __init xen_memory_setup(void)
732 {
733         unsigned long max_pfn, pfn_s, n_pfns;
734         phys_addr_t mem_end, addr, size, chunk_size;
735         u32 type;
736         int rc;
737         struct xen_memory_map memmap;
738         unsigned long max_pages;
739         unsigned long extra_pages = 0;
740         int i;
741         int op;
742 
743         xen_parse_512gb();
744         max_pfn = xen_get_pages_limit();
745         max_pfn = min(max_pfn, xen_start_info->nr_pages);
746         mem_end = PFN_PHYS(max_pfn);
747 
748         memmap.nr_entries = ARRAY_SIZE(xen_e820_table.entries);
749         set_xen_guest_handle(memmap.buffer, xen_e820_table.entries);
750 
751         op = xen_initial_domain() ?
752                 XENMEM_machine_memory_map :
753                 XENMEM_memory_map;
754         rc = HYPERVISOR_memory_op(op, &memmap);
755         if (rc == -ENOSYS) {
756                 BUG_ON(xen_initial_domain());
757                 memmap.nr_entries = 1;
758                 xen_e820_table.entries[0].addr = 0ULL;
759                 xen_e820_table.entries[0].size = mem_end;
760                 /* 8MB slack (to balance backend allocations). */
761                 xen_e820_table.entries[0].size += 8ULL << 20;
762                 xen_e820_table.entries[0].type = E820_TYPE_RAM;
763                 rc = 0;
764         }
765         BUG_ON(rc);
766         BUG_ON(memmap.nr_entries == 0);
767         xen_e820_table.nr_entries = memmap.nr_entries;
768 
769         /*
770          * Xen won't allow a 1:1 mapping to be created to UNUSABLE
771          * regions, so if we're using the machine memory map leave the
772          * region as RAM as it is in the pseudo-physical map.
773          *
774          * UNUSABLE regions in domUs are not handled and will need
775          * a patch in the future.
776          */
777         if (xen_initial_domain())
778                 xen_ignore_unusable();
779 
780         /* Make sure the Xen-supplied memory map is well-ordered. */
781         e820__update_table(&xen_e820_table);
782 
783         max_pages = xen_get_max_pages();
784 
785         /* How many extra pages do we need due to remapping? */
786         max_pages += xen_foreach_remap_area(max_pfn, xen_count_remap_pages);
787 
788         if (max_pages > max_pfn)
789                 extra_pages += max_pages - max_pfn;
790 
791         /*
792          * Clamp the amount of extra memory to a EXTRA_MEM_RATIO
793          * factor the base size.  On non-highmem systems, the base
794          * size is the full initial memory allocation; on highmem it
795          * is limited to the max size of lowmem, so that it doesn't
796          * get completely filled.
797          *
798          * Make sure we have no memory above max_pages, as this area
799          * isn't handled by the p2m management.
800          *
801          * In principle there could be a problem in lowmem systems if
802          * the initial memory is also very large with respect to
803          * lowmem, but we won't try to deal with that here.
804          */
805         extra_pages = min3(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
806                            extra_pages, max_pages - max_pfn);
807         i = 0;
808         addr = xen_e820_table.entries[0].addr;
809         size = xen_e820_table.entries[0].size;
810         while (i < xen_e820_table.nr_entries) {
811 
812                 chunk_size = size;
813                 type = xen_e820_table.entries[i].type;
814 
815                 if (type == E820_TYPE_RAM) {
816                         if (addr < mem_end) {
817                                 chunk_size = min(size, mem_end - addr);
818                         } else if (extra_pages) {
819                                 chunk_size = min(size, PFN_PHYS(extra_pages));
820                                 pfn_s = PFN_UP(addr);
821                                 n_pfns = PFN_DOWN(addr + chunk_size) - pfn_s;
822                                 extra_pages -= n_pfns;
823                                 xen_add_extra_mem(pfn_s, n_pfns);
824                                 xen_max_p2m_pfn = pfn_s + n_pfns;
825                         } else
826                                 type = E820_TYPE_UNUSABLE;
827                 }
828 
829                 xen_align_and_add_e820_region(addr, chunk_size, type);
830 
831                 addr += chunk_size;
832                 size -= chunk_size;
833                 if (size == 0) {
834                         i++;
835                         if (i < xen_e820_table.nr_entries) {
836                                 addr = xen_e820_table.entries[i].addr;
837                                 size = xen_e820_table.entries[i].size;
838                         }
839                 }
840         }
841 
842         /*
843          * Set the rest as identity mapped, in case PCI BARs are
844          * located here.
845          */
846         set_phys_range_identity(addr / PAGE_SIZE, ~0ul);
847 
848         /*
849          * In domU, the ISA region is normal, usable memory, but we
850          * reserve ISA memory anyway because too many things poke
851          * about in there.
852          */
853         e820__range_add(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS, E820_TYPE_RESERVED);
854 
855         e820__update_table(e820_table);
856 
857         /*
858          * Check whether the kernel itself conflicts with the target E820 map.
859          * Failing now is better than running into weird problems later due
860          * to relocating (and even reusing) pages with kernel text or data.
861          */
862         if (xen_is_e820_reserved(__pa_symbol(_text),
863                         __pa_symbol(__bss_stop) - __pa_symbol(_text))) {
864                 xen_raw_console_write("Xen hypervisor allocated kernel memory conflicts with E820 map\n");
865                 BUG();
866         }
867 
868         /*
869          * Check for a conflict of the hypervisor supplied page tables with
870          * the target E820 map.
871          */
872         xen_pt_check_e820();
873 
874         xen_reserve_xen_mfnlist();
875 
876         /* Check for a conflict of the initrd with the target E820 map. */
877         if (xen_is_e820_reserved(boot_params.hdr.ramdisk_image,
878                                  boot_params.hdr.ramdisk_size)) {
879                 phys_addr_t new_area, start, size;
880 
881                 new_area = xen_find_free_area(boot_params.hdr.ramdisk_size);
882                 if (!new_area) {
883                         xen_raw_console_write("Can't find new memory area for initrd needed due to E820 map conflict\n");
884                         BUG();
885                 }
886 
887                 start = boot_params.hdr.ramdisk_image;
888                 size = boot_params.hdr.ramdisk_size;
889                 xen_phys_memcpy(new_area, start, size);
890                 pr_info("initrd moved from [mem %#010llx-%#010llx] to [mem %#010llx-%#010llx]\n",
891                         start, start + size, new_area, new_area + size);
892                 memblock_free(start, size);
893                 boot_params.hdr.ramdisk_image = new_area;
894                 boot_params.ext_ramdisk_image = new_area >> 32;
895         }
896 
897         /*
898          * Set identity map on non-RAM pages and prepare remapping the
899          * underlying RAM.
900          */
901         xen_foreach_remap_area(max_pfn, xen_set_identity_and_remap_chunk);
902 
903         pr_info("Released %ld page(s)\n", xen_released_pages);
904 
905         return "Xen";
906 }
907 
908 /*
909  * Set the bit indicating "nosegneg" library variants should be used.
910  * We only need to bother in pure 32-bit mode; compat 32-bit processes
911  * can have un-truncated segments, so wrapping around is allowed.
912  */
913 static void __init fiddle_vdso(void)
914 {
915 #ifdef CONFIG_X86_32
916         u32 *mask = vdso_image_32.data +
917                 vdso_image_32.sym_VDSO32_NOTE_MASK;
918         *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
919 #endif
920 }
921 
922 static int register_callback(unsigned type, const void *func)
923 {
924         struct callback_register callback = {
925                 .type = type,
926                 .address = XEN_CALLBACK(__KERNEL_CS, func),
927                 .flags = CALLBACKF_mask_events,
928         };
929 
930         return HYPERVISOR_callback_op(CALLBACKOP_register, &callback);
931 }
932 
933 void xen_enable_sysenter(void)
934 {
935         int ret;
936         unsigned sysenter_feature;
937 
938 #ifdef CONFIG_X86_32
939         sysenter_feature = X86_FEATURE_SEP;
940 #else
941         sysenter_feature = X86_FEATURE_SYSENTER32;
942 #endif
943 
944         if (!boot_cpu_has(sysenter_feature))
945                 return;
946 
947         ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target);
948         if(ret != 0)
949                 setup_clear_cpu_cap(sysenter_feature);
950 }
951 
952 void xen_enable_syscall(void)
953 {
954 #ifdef CONFIG_X86_64
955         int ret;
956 
957         ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target);
958         if (ret != 0) {
959                 printk(KERN_ERR "Failed to set syscall callback: %d\n", ret);
960                 /* Pretty fatal; 64-bit userspace has no other
961                    mechanism for syscalls. */
962         }
963 
964         if (boot_cpu_has(X86_FEATURE_SYSCALL32)) {
965                 ret = register_callback(CALLBACKTYPE_syscall32,
966                                         xen_syscall32_target);
967                 if (ret != 0)
968                         setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
969         }
970 #endif /* CONFIG_X86_64 */
971 }
972 
973 void __init xen_pvmmu_arch_setup(void)
974 {
975         HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
976         HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);
977 
978         HYPERVISOR_vm_assist(VMASST_CMD_enable,
979                              VMASST_TYPE_pae_extended_cr3);
980 
981         if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||
982             register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
983                 BUG();
984 
985         xen_enable_sysenter();
986         xen_enable_syscall();
987 }
988 
989 /* This function is not called for HVM domains */
990 void __init xen_arch_setup(void)
991 {
992         xen_panic_handler_init();
993         xen_pvmmu_arch_setup();
994 
995 #ifdef CONFIG_ACPI
996         if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
997                 printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
998                 disable_acpi();
999         }
1000 #endif
1001 
1002         memcpy(boot_command_line, xen_start_info->cmd_line,
1003                MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
1004                COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
1005 
1006         /* Set up idle, making sure it calls safe_halt() pvop */
1007         disable_cpuidle();
1008         disable_cpufreq();
1009         WARN_ON(xen_set_default_idle());
1010         fiddle_vdso();
1011 #ifdef CONFIG_NUMA
1012         numa_off = 1;
1013 #endif
1014 }
1015 

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