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