arch/x86/xen/enlighten

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This source file includes following definitions.
xen_banner
xen_pv_init_platform
xen_pv_guest_late_init
xen_running_on_version_or_later
xen_cpuid
xen_check_mwait
xen_check_xsave
xen_init_capabilities
xen_set_debugreg
xen_get_debugreg
xen_end_context_switch
xen_store_tr
set_aliased_prot
xen_alloc_ldt
xen_free_ldt
xen_set_ldt
xen_load_gdt
xen_load_gdt_boot
desc_equal
load_TLS_descriptor
xen_load_tls
xen_load_gs_index
xen_write_ldt_entry
get_trap_addr
cvt_gate_to_trap
xen_write_idt_entry
xen_convert_trap_info
xen_copy_trap_info
xen_load_idt
xen_write_gdt_entry
xen_write_gdt_entry_boot
xen_load_sp0
xen_set_iopl_mask
xen_io_delay
xen_read_cr0
xen_write_cr0
xen_write_cr4
xen_read_msr_safe
xen_write_msr_safe
xen_read_msr
xen_write_msr
xen_setup_vcpu_info_placement
xen_restart
xen_machine_halt
xen_machine_power_off
xen_crash_shutdown
xen_get_nmi_reason
xen_boot_params_init_edd
xen_setup_gdt
xen_dom0_set_legacy_features
xen_start_kernel
xen_cpu_up_prepare_pv
xen_cpu_dead_pv
xen_platform_pv
   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Core of Xen paravirt_ops implementation.
   4  *
   5  * This file contains the xen_paravirt_ops structure itself, and the
   6  * implementations for:
   7  * - privileged instructions
   8  * - interrupt flags
   9  * - segment operations
  10  * - booting and setup
  11  *
  12  * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
  13  */
  14 
  15 #include <linux/cpu.h>
  16 #include <linux/kernel.h>
  17 #include <linux/init.h>
  18 #include <linux/smp.h>
  19 #include <linux/preempt.h>
  20 #include <linux/hardirq.h>
  21 #include <linux/percpu.h>
  22 #include <linux/delay.h>
  23 #include <linux/start_kernel.h>
  24 #include <linux/sched.h>
  25 #include <linux/kprobes.h>
  26 #include <linux/memblock.h>
  27 #include <linux/export.h>
  28 #include <linux/mm.h>
  29 #include <linux/page-flags.h>
  30 #include <linux/highmem.h>
  31 #include <linux/console.h>
  32 #include <linux/pci.h>
  33 #include <linux/gfp.h>
  34 #include <linux/edd.h>
  35 #include <linux/frame.h>
  36 
  37 #include <xen/xen.h>
  38 #include <xen/events.h>
  39 #include <xen/interface/xen.h>
  40 #include <xen/interface/version.h>
  41 #include <xen/interface/physdev.h>
  42 #include <xen/interface/vcpu.h>
  43 #include <xen/interface/memory.h>
  44 #include <xen/interface/nmi.h>
  45 #include <xen/interface/xen-mca.h>
  46 #include <xen/features.h>
  47 #include <xen/page.h>
  48 #include <xen/hvc-console.h>
  49 #include <xen/acpi.h>
  50 
  51 #include <asm/paravirt.h>
  52 #include <asm/apic.h>
  53 #include <asm/page.h>
  54 #include <asm/xen/pci.h>
  55 #include <asm/xen/hypercall.h>
  56 #include <asm/xen/hypervisor.h>
  57 #include <asm/xen/cpuid.h>
  58 #include <asm/fixmap.h>
  59 #include <asm/processor.h>
  60 #include <asm/proto.h>
  61 #include <asm/msr-index.h>
  62 #include <asm/traps.h>
  63 #include <asm/setup.h>
  64 #include <asm/desc.h>
  65 #include <asm/pgalloc.h>
  66 #include <asm/pgtable.h>
  67 #include <asm/tlbflush.h>
  68 #include <asm/reboot.h>
  69 #include <asm/stackprotector.h>
  70 #include <asm/hypervisor.h>
  71 #include <asm/mach_traps.h>
  72 #include <asm/mwait.h>
  73 #include <asm/pci_x86.h>
  74 #include <asm/cpu.h>
  75 
  76 #ifdef CONFIG_ACPI
  77 #include <linux/acpi.h>
  78 #include <asm/acpi.h>
  79 #include <acpi/pdc_intel.h>
  80 #include <acpi/processor.h>
  81 #include <xen/interface/platform.h>
  82 #endif
  83 
  84 #include "xen-ops.h"
  85 #include "mmu.h"
  86 #include "smp.h"
  87 #include "multicalls.h"
  88 #include "pmu.h"
  89 
  90 #include "../kernel/cpu/cpu.h" /* get_cpu_cap() */
  91 
  92 void *xen_initial_gdt;
  93 
  94 static int xen_cpu_up_prepare_pv(unsigned int cpu);
  95 static int xen_cpu_dead_pv(unsigned int cpu);
  96 
  97 struct tls_descs {
  98         struct desc_struct desc[3];
  99 };
 100 
 101 /*
 102  * Updating the 3 TLS descriptors in the GDT on every task switch is
 103  * surprisingly expensive so we avoid updating them if they haven't
 104  * changed.  Since Xen writes different descriptors than the one
 105  * passed in the update_descriptor hypercall we keep shadow copies to
 106  * compare against.
 107  */
 108 static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc);
 109 
 110 static void __init xen_banner(void)
 111 {
 112         unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL);
 113         struct xen_extraversion extra;
 114         HYPERVISOR_xen_version(XENVER_extraversion, &extra);
 115 
 116         pr_info("Booting paravirtualized kernel on %s\n", pv_info.name);
 117         printk(KERN_INFO "Xen version: %d.%d%s%s\n",
 118                version >> 16, version & 0xffff, extra.extraversion,
 119                xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : "");
 120 
 121 #ifdef CONFIG_X86_32
 122         pr_warn("WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING!\n"
 123                 "Support for running as 32-bit PV-guest under Xen will soon be removed\n"
 124                 "from the Linux kernel!\n"
 125                 "Please use either a 64-bit kernel or switch to HVM or PVH mode!\n"
 126                 "WARNING! WARNING! WARNING! WARNING! WARNING! WARNING! WARNING!\n");
 127 #endif
 128 }
 129 
 130 static void __init xen_pv_init_platform(void)
 131 {
 132         populate_extra_pte(fix_to_virt(FIX_PARAVIRT_BOOTMAP));
 133 
 134         set_fixmap(FIX_PARAVIRT_BOOTMAP, xen_start_info->shared_info);
 135         HYPERVISOR_shared_info = (void *)fix_to_virt(FIX_PARAVIRT_BOOTMAP);
 136 
 137         /* xen clock uses per-cpu vcpu_info, need to init it for boot cpu */
 138         xen_vcpu_info_reset(0);
 139 
 140         /* pvclock is in shared info area */
 141         xen_init_time_ops();
 142 }
 143 
 144 static void __init xen_pv_guest_late_init(void)
 145 {
 146 #ifndef CONFIG_SMP
 147         /* Setup shared vcpu info for non-smp configurations */
 148         xen_setup_vcpu_info_placement();
 149 #endif
 150 }
 151 
 152 /* Check if running on Xen version (major, minor) or later */
 153 bool
 154 xen_running_on_version_or_later(unsigned int major, unsigned int minor)
 155 {
 156         unsigned int version;
 157 
 158         if (!xen_domain())
 159                 return false;
 160 
 161         version = HYPERVISOR_xen_version(XENVER_version, NULL);
 162         if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) ||
 163                 ((version >> 16) > major))
 164                 return true;
 165         return false;
 166 }
 167 
 168 static __read_mostly unsigned int cpuid_leaf5_ecx_val;
 169 static __read_mostly unsigned int cpuid_leaf5_edx_val;
 170 
 171 static void xen_cpuid(unsigned int *ax, unsigned int *bx,
 172                       unsigned int *cx, unsigned int *dx)
 173 {
 174         unsigned maskebx = ~0;
 175 
 176         /*
 177          * Mask out inconvenient features, to try and disable as many
 178          * unsupported kernel subsystems as possible.
 179          */
 180         switch (*ax) {
 181         case CPUID_MWAIT_LEAF:
 182                 /* Synthesize the values.. */
 183                 *ax = 0;
 184                 *bx = 0;
 185                 *cx = cpuid_leaf5_ecx_val;
 186                 *dx = cpuid_leaf5_edx_val;
 187                 return;
 188 
 189         case 0xb:
 190                 /* Suppress extended topology stuff */
 191                 maskebx = 0;
 192                 break;
 193         }
 194 
 195         asm(XEN_EMULATE_PREFIX "cpuid"
 196                 : "=a" (*ax),
 197                   "=b" (*bx),
 198                   "=c" (*cx),
 199                   "=d" (*dx)
 200                 : "0" (*ax), "2" (*cx));
 201 
 202         *bx &= maskebx;
 203 }
 204 STACK_FRAME_NON_STANDARD(xen_cpuid); /* XEN_EMULATE_PREFIX */
 205 
 206 static bool __init xen_check_mwait(void)
 207 {
 208 #ifdef CONFIG_ACPI
 209         struct xen_platform_op op = {
 210                 .cmd                    = XENPF_set_processor_pminfo,
 211                 .u.set_pminfo.id        = -1,
 212                 .u.set_pminfo.type      = XEN_PM_PDC,
 213         };
 214         uint32_t buf[3];
 215         unsigned int ax, bx, cx, dx;
 216         unsigned int mwait_mask;
 217 
 218         /* We need to determine whether it is OK to expose the MWAIT
 219          * capability to the kernel to harvest deeper than C3 states from ACPI
 220          * _CST using the processor_harvest_xen.c module. For this to work, we
 221          * need to gather the MWAIT_LEAF values (which the cstate.c code
 222          * checks against). The hypervisor won't expose the MWAIT flag because
 223          * it would break backwards compatibility; so we will find out directly
 224          * from the hardware and hypercall.
 225          */
 226         if (!xen_initial_domain())
 227                 return false;
 228 
 229         /*
 230          * When running under platform earlier than Xen4.2, do not expose
 231          * mwait, to avoid the risk of loading native acpi pad driver
 232          */
 233         if (!xen_running_on_version_or_later(4, 2))
 234                 return false;
 235 
 236         ax = 1;
 237         cx = 0;
 238 
 239         native_cpuid(&ax, &bx, &cx, &dx);
 240 
 241         mwait_mask = (1 << (X86_FEATURE_EST % 32)) |
 242                      (1 << (X86_FEATURE_MWAIT % 32));
 243 
 244         if ((cx & mwait_mask) != mwait_mask)
 245                 return false;
 246 
 247         /* We need to emulate the MWAIT_LEAF and for that we need both
 248          * ecx and edx. The hypercall provides only partial information.
 249          */
 250 
 251         ax = CPUID_MWAIT_LEAF;
 252         bx = 0;
 253         cx = 0;
 254         dx = 0;
 255 
 256         native_cpuid(&ax, &bx, &cx, &dx);
 257 
 258         /* Ask the Hypervisor whether to clear ACPI_PDC_C_C2C3_FFH. If so,
 259          * don't expose MWAIT_LEAF and let ACPI pick the IOPORT version of C3.
 260          */
 261         buf[0] = ACPI_PDC_REVISION_ID;
 262         buf[1] = 1;
 263         buf[2] = (ACPI_PDC_C_CAPABILITY_SMP | ACPI_PDC_EST_CAPABILITY_SWSMP);
 264 
 265         set_xen_guest_handle(op.u.set_pminfo.pdc, buf);
 266 
 267         if ((HYPERVISOR_platform_op(&op) == 0) &&
 268             (buf[2] & (ACPI_PDC_C_C1_FFH | ACPI_PDC_C_C2C3_FFH))) {
 269                 cpuid_leaf5_ecx_val = cx;
 270                 cpuid_leaf5_edx_val = dx;
 271         }
 272         return true;
 273 #else
 274         return false;
 275 #endif
 276 }
 277 
 278 static bool __init xen_check_xsave(void)
 279 {
 280         unsigned int cx, xsave_mask;
 281 
 282         cx = cpuid_ecx(1);
 283 
 284         xsave_mask = (1 << (X86_FEATURE_XSAVE % 32)) |
 285                      (1 << (X86_FEATURE_OSXSAVE % 32));
 286 
 287         /* Xen will set CR4.OSXSAVE if supported and not disabled by force */
 288         return (cx & xsave_mask) == xsave_mask;
 289 }
 290 
 291 static void __init xen_init_capabilities(void)
 292 {
 293         setup_force_cpu_cap(X86_FEATURE_XENPV);
 294         setup_clear_cpu_cap(X86_FEATURE_DCA);
 295         setup_clear_cpu_cap(X86_FEATURE_APERFMPERF);
 296         setup_clear_cpu_cap(X86_FEATURE_MTRR);
 297         setup_clear_cpu_cap(X86_FEATURE_ACC);
 298         setup_clear_cpu_cap(X86_FEATURE_X2APIC);
 299         setup_clear_cpu_cap(X86_FEATURE_SME);
 300 
 301         /*
 302          * Xen PV would need some work to support PCID: CR3 handling as well
 303          * as xen_flush_tlb_others() would need updating.
 304          */
 305         setup_clear_cpu_cap(X86_FEATURE_PCID);
 306 
 307         if (!xen_initial_domain())
 308                 setup_clear_cpu_cap(X86_FEATURE_ACPI);
 309 
 310         if (xen_check_mwait())
 311                 setup_force_cpu_cap(X86_FEATURE_MWAIT);
 312         else
 313                 setup_clear_cpu_cap(X86_FEATURE_MWAIT);
 314 
 315         if (!xen_check_xsave()) {
 316                 setup_clear_cpu_cap(X86_FEATURE_XSAVE);
 317                 setup_clear_cpu_cap(X86_FEATURE_OSXSAVE);
 318         }
 319 }
 320 
 321 static void xen_set_debugreg(int reg, unsigned long val)
 322 {
 323         HYPERVISOR_set_debugreg(reg, val);
 324 }
 325 
 326 static unsigned long xen_get_debugreg(int reg)
 327 {
 328         return HYPERVISOR_get_debugreg(reg);
 329 }
 330 
 331 static void xen_end_context_switch(struct task_struct *next)
 332 {
 333         xen_mc_flush();
 334         paravirt_end_context_switch(next);
 335 }
 336 
 337 static unsigned long xen_store_tr(void)
 338 {
 339         return 0;
 340 }
 341 
 342 /*
 343  * Set the page permissions for a particular virtual address.  If the
 344  * address is a vmalloc mapping (or other non-linear mapping), then
 345  * find the linear mapping of the page and also set its protections to
 346  * match.
 347  */
 348 static void set_aliased_prot(void *v, pgprot_t prot)
 349 {
 350         int level;
 351         pte_t *ptep;
 352         pte_t pte;
 353         unsigned long pfn;
 354         struct page *page;
 355         unsigned char dummy;
 356 
 357         ptep = lookup_address((unsigned long)v, &level);
 358         BUG_ON(ptep == NULL);
 359 
 360         pfn = pte_pfn(*ptep);
 361         page = pfn_to_page(pfn);
 362 
 363         pte = pfn_pte(pfn, prot);
 364 
 365         /*
 366          * Careful: update_va_mapping() will fail if the virtual address
 367          * we're poking isn't populated in the page tables.  We don't
 368          * need to worry about the direct map (that's always in the page
 369          * tables), but we need to be careful about vmap space.  In
 370          * particular, the top level page table can lazily propagate
 371          * entries between processes, so if we've switched mms since we
 372          * vmapped the target in the first place, we might not have the
 373          * top-level page table entry populated.
 374          *
 375          * We disable preemption because we want the same mm active when
 376          * we probe the target and when we issue the hypercall.  We'll
 377          * have the same nominal mm, but if we're a kernel thread, lazy
 378          * mm dropping could change our pgd.
 379          *
 380          * Out of an abundance of caution, this uses __get_user() to fault
 381          * in the target address just in case there's some obscure case
 382          * in which the target address isn't readable.
 383          */
 384 
 385         preempt_disable();
 386 
 387         probe_kernel_read(&dummy, v, 1);
 388 
 389         if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0))
 390                 BUG();
 391 
 392         if (!PageHighMem(page)) {
 393                 void *av = __va(PFN_PHYS(pfn));
 394 
 395                 if (av != v)
 396                         if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0))
 397                                 BUG();
 398         } else
 399                 kmap_flush_unused();
 400 
 401         preempt_enable();
 402 }
 403 
 404 static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries)
 405 {
 406         const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
 407         int i;
 408 
 409         /*
 410          * We need to mark the all aliases of the LDT pages RO.  We
 411          * don't need to call vm_flush_aliases(), though, since that's
 412          * only responsible for flushing aliases out the TLBs, not the
 413          * page tables, and Xen will flush the TLB for us if needed.
 414          *
 415          * To avoid confusing future readers: none of this is necessary
 416          * to load the LDT.  The hypervisor only checks this when the
 417          * LDT is faulted in due to subsequent descriptor access.
 418          */
 419 
 420         for (i = 0; i < entries; i += entries_per_page)
 421                 set_aliased_prot(ldt + i, PAGE_KERNEL_RO);
 422 }
 423 
 424 static void xen_free_ldt(struct desc_struct *ldt, unsigned entries)
 425 {
 426         const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
 427         int i;
 428 
 429         for (i = 0; i < entries; i += entries_per_page)
 430                 set_aliased_prot(ldt + i, PAGE_KERNEL);
 431 }
 432 
 433 static void xen_set_ldt(const void *addr, unsigned entries)
 434 {
 435         struct mmuext_op *op;
 436         struct multicall_space mcs = xen_mc_entry(sizeof(*op));
 437 
 438         trace_xen_cpu_set_ldt(addr, entries);
 439 
 440         op = mcs.args;
 441         op->cmd = MMUEXT_SET_LDT;
 442         op->arg1.linear_addr = (unsigned long)addr;
 443         op->arg2.nr_ents = entries;
 444 
 445         MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
 446 
 447         xen_mc_issue(PARAVIRT_LAZY_CPU);
 448 }
 449 
 450 static void xen_load_gdt(const struct desc_ptr *dtr)
 451 {
 452         unsigned long va = dtr->address;
 453         unsigned int size = dtr->size + 1;
 454         unsigned long pfn, mfn;
 455         int level;
 456         pte_t *ptep;
 457         void *virt;
 458 
 459         /* @size should be at most GDT_SIZE which is smaller than PAGE_SIZE. */
 460         BUG_ON(size > PAGE_SIZE);
 461         BUG_ON(va & ~PAGE_MASK);
 462 
 463         /*
 464          * The GDT is per-cpu and is in the percpu data area.
 465          * That can be virtually mapped, so we need to do a
 466          * page-walk to get the underlying MFN for the
 467          * hypercall.  The page can also be in the kernel's
 468          * linear range, so we need to RO that mapping too.
 469          */
 470         ptep = lookup_address(va, &level);
 471         BUG_ON(ptep == NULL);
 472 
 473         pfn = pte_pfn(*ptep);
 474         mfn = pfn_to_mfn(pfn);
 475         virt = __va(PFN_PHYS(pfn));
 476 
 477         make_lowmem_page_readonly((void *)va);
 478         make_lowmem_page_readonly(virt);
 479 
 480         if (HYPERVISOR_set_gdt(&mfn, size / sizeof(struct desc_struct)))
 481                 BUG();
 482 }
 483 
 484 /*
 485  * load_gdt for early boot, when the gdt is only mapped once
 486  */
 487 static void __init xen_load_gdt_boot(const struct desc_ptr *dtr)
 488 {
 489         unsigned long va = dtr->address;
 490         unsigned int size = dtr->size + 1;
 491         unsigned long pfn, mfn;
 492         pte_t pte;
 493 
 494         /* @size should be at most GDT_SIZE which is smaller than PAGE_SIZE. */
 495         BUG_ON(size > PAGE_SIZE);
 496         BUG_ON(va & ~PAGE_MASK);
 497 
 498         pfn = virt_to_pfn(va);
 499         mfn = pfn_to_mfn(pfn);
 500 
 501         pte = pfn_pte(pfn, PAGE_KERNEL_RO);
 502 
 503         if (HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0))
 504                 BUG();
 505 
 506         if (HYPERVISOR_set_gdt(&mfn, size / sizeof(struct desc_struct)))
 507                 BUG();
 508 }
 509 
 510 static inline bool desc_equal(const struct desc_struct *d1,
 511                               const struct desc_struct *d2)
 512 {
 513         return !memcmp(d1, d2, sizeof(*d1));
 514 }
 515 
 516 static void load_TLS_descriptor(struct thread_struct *t,
 517                                 unsigned int cpu, unsigned int i)
 518 {
 519         struct desc_struct *shadow = &per_cpu(shadow_tls_desc, cpu).desc[i];
 520         struct desc_struct *gdt;
 521         xmaddr_t maddr;
 522         struct multicall_space mc;
 523 
 524         if (desc_equal(shadow, &t->tls_array[i]))
 525                 return;
 526 
 527         *shadow = t->tls_array[i];
 528 
 529         gdt = get_cpu_gdt_rw(cpu);
 530         maddr = arbitrary_virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]);
 531         mc = __xen_mc_entry(0);
 532 
 533         MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]);
 534 }
 535 
 536 static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
 537 {
 538         /*
 539          * XXX sleazy hack: If we're being called in a lazy-cpu zone
 540          * and lazy gs handling is enabled, it means we're in a
 541          * context switch, and %gs has just been saved.  This means we
 542          * can zero it out to prevent faults on exit from the
 543          * hypervisor if the next process has no %gs.  Either way, it
 544          * has been saved, and the new value will get loaded properly.
 545          * This will go away as soon as Xen has been modified to not
 546          * save/restore %gs for normal hypercalls.
 547          *
 548          * On x86_64, this hack is not used for %gs, because gs points
 549          * to KERNEL_GS_BASE (and uses it for PDA references), so we
 550          * must not zero %gs on x86_64
 551          *
 552          * For x86_64, we need to zero %fs, otherwise we may get an
 553          * exception between the new %fs descriptor being loaded and
 554          * %fs being effectively cleared at __switch_to().
 555          */
 556         if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) {
 557 #ifdef CONFIG_X86_32
 558                 lazy_load_gs(0);
 559 #else
 560                 loadsegment(fs, 0);
 561 #endif
 562         }
 563 
 564         xen_mc_batch();
 565 
 566         load_TLS_descriptor(t, cpu, 0);
 567         load_TLS_descriptor(t, cpu, 1);
 568         load_TLS_descriptor(t, cpu, 2);
 569 
 570         xen_mc_issue(PARAVIRT_LAZY_CPU);
 571 }
 572 
 573 #ifdef CONFIG_X86_64
 574 static void xen_load_gs_index(unsigned int idx)
 575 {
 576         if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx))
 577                 BUG();
 578 }
 579 #endif
 580 
 581 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
 582                                 const void *ptr)
 583 {
 584         xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]);
 585         u64 entry = *(u64 *)ptr;
 586 
 587         trace_xen_cpu_write_ldt_entry(dt, entrynum, entry);
 588 
 589         preempt_disable();
 590 
 591         xen_mc_flush();
 592         if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry))
 593                 BUG();
 594 
 595         preempt_enable();
 596 }
 597 
 598 #ifdef CONFIG_X86_64
 599 struct trap_array_entry {
 600         void (*orig)(void);
 601         void (*xen)(void);
 602         bool ist_okay;
 603 };
 604 
 605 static struct trap_array_entry trap_array[] = {
 606         { debug,                       xen_xendebug,                    true },
 607         { double_fault,                xen_double_fault,                true },
 608 #ifdef CONFIG_X86_MCE
 609         { machine_check,               xen_machine_check,               true },
 610 #endif
 611         { nmi,                         xen_xennmi,                      true },
 612         { int3,                        xen_int3,                        false },
 613         { overflow,                    xen_overflow,                    false },
 614 #ifdef CONFIG_IA32_EMULATION
 615         { entry_INT80_compat,          xen_entry_INT80_compat,          false },
 616 #endif
 617         { page_fault,                  xen_page_fault,                  false },
 618         { divide_error,                xen_divide_error,                false },
 619         { bounds,                      xen_bounds,                      false },
 620         { invalid_op,                  xen_invalid_op,                  false },
 621         { device_not_available,        xen_device_not_available,        false },
 622         { coprocessor_segment_overrun, xen_coprocessor_segment_overrun, false },
 623         { invalid_TSS,                 xen_invalid_TSS,                 false },
 624         { segment_not_present,         xen_segment_not_present,         false },
 625         { stack_segment,               xen_stack_segment,               false },
 626         { general_protection,          xen_general_protection,          false },
 627         { spurious_interrupt_bug,      xen_spurious_interrupt_bug,      false },
 628         { coprocessor_error,           xen_coprocessor_error,           false },
 629         { alignment_check,             xen_alignment_check,             false },
 630         { simd_coprocessor_error,      xen_simd_coprocessor_error,      false },
 631 };
 632 
 633 static bool __ref get_trap_addr(void **addr, unsigned int ist)
 634 {
 635         unsigned int nr;
 636         bool ist_okay = false;
 637 
 638         /*
 639          * Replace trap handler addresses by Xen specific ones.
 640          * Check for known traps using IST and whitelist them.
 641          * The debugger ones are the only ones we care about.
 642          * Xen will handle faults like double_fault, * so we should never see
 643          * them.  Warn if there's an unexpected IST-using fault handler.
 644          */
 645         for (nr = 0; nr < ARRAY_SIZE(trap_array); nr++) {
 646                 struct trap_array_entry *entry = trap_array + nr;
 647 
 648                 if (*addr == entry->orig) {
 649                         *addr = entry->xen;
 650                         ist_okay = entry->ist_okay;
 651                         break;
 652                 }
 653         }
 654 
 655         if (nr == ARRAY_SIZE(trap_array) &&
 656             *addr >= (void *)early_idt_handler_array[0] &&
 657             *addr < (void *)early_idt_handler_array[NUM_EXCEPTION_VECTORS]) {
 658                 nr = (*addr - (void *)early_idt_handler_array[0]) /
 659                      EARLY_IDT_HANDLER_SIZE;
 660                 *addr = (void *)xen_early_idt_handler_array[nr];
 661         }
 662 
 663         if (WARN_ON(ist != 0 && !ist_okay))
 664                 return false;
 665 
 666         return true;
 667 }
 668 #endif
 669 
 670 static int cvt_gate_to_trap(int vector, const gate_desc *val,
 671                             struct trap_info *info)
 672 {
 673         unsigned long addr;
 674 
 675         if (val->bits.type != GATE_TRAP && val->bits.type != GATE_INTERRUPT)
 676                 return 0;
 677 
 678         info->vector = vector;
 679 
 680         addr = gate_offset(val);
 681 #ifdef CONFIG_X86_64
 682         if (!get_trap_addr((void **)&addr, val->bits.ist))
 683                 return 0;
 684 #endif  /* CONFIG_X86_64 */
 685         info->address = addr;
 686 
 687         info->cs = gate_segment(val);
 688         info->flags = val->bits.dpl;
 689         /* interrupt gates clear IF */
 690         if (val->bits.type == GATE_INTERRUPT)
 691                 info->flags |= 1 << 2;
 692 
 693         return 1;
 694 }
 695 
 696 /* Locations of each CPU's IDT */
 697 static DEFINE_PER_CPU(struct desc_ptr, idt_desc);
 698 
 699 /* Set an IDT entry.  If the entry is part of the current IDT, then
 700    also update Xen. */
 701 static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g)
 702 {
 703         unsigned long p = (unsigned long)&dt[entrynum];
 704         unsigned long start, end;
 705 
 706         trace_xen_cpu_write_idt_entry(dt, entrynum, g);
 707 
 708         preempt_disable();
 709 
 710         start = __this_cpu_read(idt_desc.address);
 711         end = start + __this_cpu_read(idt_desc.size) + 1;
 712 
 713         xen_mc_flush();
 714 
 715         native_write_idt_entry(dt, entrynum, g);
 716 
 717         if (p >= start && (p + 8) <= end) {
 718                 struct trap_info info[2];
 719 
 720                 info[1].address = 0;
 721 
 722                 if (cvt_gate_to_trap(entrynum, g, &info[0]))
 723                         if (HYPERVISOR_set_trap_table(info))
 724                                 BUG();
 725         }
 726 
 727         preempt_enable();
 728 }
 729 
 730 static void xen_convert_trap_info(const struct desc_ptr *desc,
 731                                   struct trap_info *traps)
 732 {
 733         unsigned in, out, count;
 734 
 735         count = (desc->size+1) / sizeof(gate_desc);
 736         BUG_ON(count > 256);
 737 
 738         for (in = out = 0; in < count; in++) {
 739                 gate_desc *entry = (gate_desc *)(desc->address) + in;
 740 
 741                 if (cvt_gate_to_trap(in, entry, &traps[out]))
 742                         out++;
 743         }
 744         traps[out].address = 0;
 745 }
 746 
 747 void xen_copy_trap_info(struct trap_info *traps)
 748 {
 749         const struct desc_ptr *desc = this_cpu_ptr(&idt_desc);
 750 
 751         xen_convert_trap_info(desc, traps);
 752 }
 753 
 754 /* Load a new IDT into Xen.  In principle this can be per-CPU, so we
 755    hold a spinlock to protect the static traps[] array (static because
 756    it avoids allocation, and saves stack space). */
 757 static void xen_load_idt(const struct desc_ptr *desc)
 758 {
 759         static DEFINE_SPINLOCK(lock);
 760         static struct trap_info traps[257];
 761 
 762         trace_xen_cpu_load_idt(desc);
 763 
 764         spin_lock(&lock);
 765 
 766         memcpy(this_cpu_ptr(&idt_desc), desc, sizeof(idt_desc));
 767 
 768         xen_convert_trap_info(desc, traps);
 769 
 770         xen_mc_flush();
 771         if (HYPERVISOR_set_trap_table(traps))
 772                 BUG();
 773 
 774         spin_unlock(&lock);
 775 }
 776 
 777 /* Write a GDT descriptor entry.  Ignore LDT descriptors, since
 778    they're handled differently. */
 779 static void xen_write_gdt_entry(struct desc_struct *dt, int entry,
 780                                 const void *desc, int type)
 781 {
 782         trace_xen_cpu_write_gdt_entry(dt, entry, desc, type);
 783 
 784         preempt_disable();
 785 
 786         switch (type) {
 787         case DESC_LDT:
 788         case DESC_TSS:
 789                 /* ignore */
 790                 break;
 791 
 792         default: {
 793                 xmaddr_t maddr = arbitrary_virt_to_machine(&dt[entry]);
 794 
 795                 xen_mc_flush();
 796                 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
 797                         BUG();
 798         }
 799 
 800         }
 801 
 802         preempt_enable();
 803 }
 804 
 805 /*
 806  * Version of write_gdt_entry for use at early boot-time needed to
 807  * update an entry as simply as possible.
 808  */
 809 static void __init xen_write_gdt_entry_boot(struct desc_struct *dt, int entry,
 810                                             const void *desc, int type)
 811 {
 812         trace_xen_cpu_write_gdt_entry(dt, entry, desc, type);
 813 
 814         switch (type) {
 815         case DESC_LDT:
 816         case DESC_TSS:
 817                 /* ignore */
 818                 break;
 819 
 820         default: {
 821                 xmaddr_t maddr = virt_to_machine(&dt[entry]);
 822 
 823                 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
 824                         dt[entry] = *(struct desc_struct *)desc;
 825         }
 826 
 827         }
 828 }
 829 
 830 static void xen_load_sp0(unsigned long sp0)
 831 {
 832         struct multicall_space mcs;
 833 
 834         mcs = xen_mc_entry(0);
 835         MULTI_stack_switch(mcs.mc, __KERNEL_DS, sp0);
 836         xen_mc_issue(PARAVIRT_LAZY_CPU);
 837         this_cpu_write(cpu_tss_rw.x86_tss.sp0, sp0);
 838 }
 839 
 840 void xen_set_iopl_mask(unsigned mask)
 841 {
 842         struct physdev_set_iopl set_iopl;
 843 
 844         /* Force the change at ring 0. */
 845         set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3;
 846         HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
 847 }
 848 
 849 static void xen_io_delay(void)
 850 {
 851 }
 852 
 853 static DEFINE_PER_CPU(unsigned long, xen_cr0_value);
 854 
 855 static unsigned long xen_read_cr0(void)
 856 {
 857         unsigned long cr0 = this_cpu_read(xen_cr0_value);
 858 
 859         if (unlikely(cr0 == 0)) {
 860                 cr0 = native_read_cr0();
 861                 this_cpu_write(xen_cr0_value, cr0);
 862         }
 863 
 864         return cr0;
 865 }
 866 
 867 static void xen_write_cr0(unsigned long cr0)
 868 {
 869         struct multicall_space mcs;
 870 
 871         this_cpu_write(xen_cr0_value, cr0);
 872 
 873         /* Only pay attention to cr0.TS; everything else is
 874            ignored. */
 875         mcs = xen_mc_entry(0);
 876 
 877         MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0);
 878 
 879         xen_mc_issue(PARAVIRT_LAZY_CPU);
 880 }
 881 
 882 static void xen_write_cr4(unsigned long cr4)
 883 {
 884         cr4 &= ~(X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PCE);
 885 
 886         native_write_cr4(cr4);
 887 }
 888 
 889 static u64 xen_read_msr_safe(unsigned int msr, int *err)
 890 {
 891         u64 val;
 892 
 893         if (pmu_msr_read(msr, &val, err))
 894                 return val;
 895 
 896         val = native_read_msr_safe(msr, err);
 897         switch (msr) {
 898         case MSR_IA32_APICBASE:
 899                 val &= ~X2APIC_ENABLE;
 900                 break;
 901         }
 902         return val;
 903 }
 904 
 905 static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
 906 {
 907         int ret;
 908 #ifdef CONFIG_X86_64
 909         unsigned int which;
 910         u64 base;
 911 #endif
 912 
 913         ret = 0;
 914 
 915         switch (msr) {
 916 #ifdef CONFIG_X86_64
 917         case MSR_FS_BASE:               which = SEGBASE_FS; goto set;
 918         case MSR_KERNEL_GS_BASE:        which = SEGBASE_GS_USER; goto set;
 919         case MSR_GS_BASE:               which = SEGBASE_GS_KERNEL; goto set;
 920 
 921         set:
 922                 base = ((u64)high << 32) | low;
 923                 if (HYPERVISOR_set_segment_base(which, base) != 0)
 924                         ret = -EIO;
 925                 break;
 926 #endif
 927 
 928         case MSR_STAR:
 929         case MSR_CSTAR:
 930         case MSR_LSTAR:
 931         case MSR_SYSCALL_MASK:
 932         case MSR_IA32_SYSENTER_CS:
 933         case MSR_IA32_SYSENTER_ESP:
 934         case MSR_IA32_SYSENTER_EIP:
 935                 /* Fast syscall setup is all done in hypercalls, so
 936                    these are all ignored.  Stub them out here to stop
 937                    Xen console noise. */
 938                 break;
 939 
 940         default:
 941                 if (!pmu_msr_write(msr, low, high, &ret))
 942                         ret = native_write_msr_safe(msr, low, high);
 943         }
 944 
 945         return ret;
 946 }
 947 
 948 static u64 xen_read_msr(unsigned int msr)
 949 {
 950         /*
 951          * This will silently swallow a #GP from RDMSR.  It may be worth
 952          * changing that.
 953          */
 954         int err;
 955 
 956         return xen_read_msr_safe(msr, &err);
 957 }
 958 
 959 static void xen_write_msr(unsigned int msr, unsigned low, unsigned high)
 960 {
 961         /*
 962          * This will silently swallow a #GP from WRMSR.  It may be worth
 963          * changing that.
 964          */
 965         xen_write_msr_safe(msr, low, high);
 966 }
 967 
 968 /* This is called once we have the cpu_possible_mask */
 969 void __init xen_setup_vcpu_info_placement(void)
 970 {
 971         int cpu;
 972 
 973         for_each_possible_cpu(cpu) {
 974                 /* Set up direct vCPU id mapping for PV guests. */
 975                 per_cpu(xen_vcpu_id, cpu) = cpu;
 976 
 977                 /*
 978                  * xen_vcpu_setup(cpu) can fail  -- in which case it
 979                  * falls back to the shared_info version for cpus
 980                  * where xen_vcpu_nr(cpu) < MAX_VIRT_CPUS.
 981                  *
 982                  * xen_cpu_up_prepare_pv() handles the rest by failing
 983                  * them in hotplug.
 984                  */
 985                 (void) xen_vcpu_setup(cpu);
 986         }
 987 
 988         /*
 989          * xen_vcpu_setup managed to place the vcpu_info within the
 990          * percpu area for all cpus, so make use of it.
 991          */
 992         if (xen_have_vcpu_info_placement) {
 993                 pv_ops.irq.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct);
 994                 pv_ops.irq.restore_fl =
 995                         __PV_IS_CALLEE_SAVE(xen_restore_fl_direct);
 996                 pv_ops.irq.irq_disable =
 997                         __PV_IS_CALLEE_SAVE(xen_irq_disable_direct);
 998                 pv_ops.irq.irq_enable =
 999                         __PV_IS_CALLEE_SAVE(xen_irq_enable_direct);
1000                 pv_ops.mmu.read_cr2 =
1001                         __PV_IS_CALLEE_SAVE(xen_read_cr2_direct);
1002         }
1003 }
1004 
1005 static const struct pv_info xen_info __initconst = {
1006         .shared_kernel_pmd = 0,
1007 
1008 #ifdef CONFIG_X86_64
1009         .extra_user_64bit_cs = FLAT_USER_CS64,
1010 #endif
1011         .name = "Xen",
1012 };
1013 
1014 static const struct pv_cpu_ops xen_cpu_ops __initconst = {
1015         .cpuid = xen_cpuid,
1016 
1017         .set_debugreg = xen_set_debugreg,
1018         .get_debugreg = xen_get_debugreg,
1019 
1020         .read_cr0 = xen_read_cr0,
1021         .write_cr0 = xen_write_cr0,
1022 
1023         .write_cr4 = xen_write_cr4,
1024 
1025         .wbinvd = native_wbinvd,
1026 
1027         .read_msr = xen_read_msr,
1028         .write_msr = xen_write_msr,
1029 
1030         .read_msr_safe = xen_read_msr_safe,
1031         .write_msr_safe = xen_write_msr_safe,
1032 
1033         .read_pmc = xen_read_pmc,
1034 
1035         .iret = xen_iret,
1036 #ifdef CONFIG_X86_64
1037         .usergs_sysret64 = xen_sysret64,
1038 #endif
1039 
1040         .load_tr_desc = paravirt_nop,
1041         .set_ldt = xen_set_ldt,
1042         .load_gdt = xen_load_gdt,
1043         .load_idt = xen_load_idt,
1044         .load_tls = xen_load_tls,
1045 #ifdef CONFIG_X86_64
1046         .load_gs_index = xen_load_gs_index,
1047 #endif
1048 
1049         .alloc_ldt = xen_alloc_ldt,
1050         .free_ldt = xen_free_ldt,
1051 
1052         .store_tr = xen_store_tr,
1053 
1054         .write_ldt_entry = xen_write_ldt_entry,
1055         .write_gdt_entry = xen_write_gdt_entry,
1056         .write_idt_entry = xen_write_idt_entry,
1057         .load_sp0 = xen_load_sp0,
1058 
1059         .set_iopl_mask = xen_set_iopl_mask,
1060         .io_delay = xen_io_delay,
1061 
1062         /* Xen takes care of %gs when switching to usermode for us */
1063         .swapgs = paravirt_nop,
1064 
1065         .start_context_switch = paravirt_start_context_switch,
1066         .end_context_switch = xen_end_context_switch,
1067 };
1068 
1069 static void xen_restart(char *msg)
1070 {
1071         xen_reboot(SHUTDOWN_reboot);
1072 }
1073 
1074 static void xen_machine_halt(void)
1075 {
1076         xen_reboot(SHUTDOWN_poweroff);
1077 }
1078 
1079 static void xen_machine_power_off(void)
1080 {
1081         if (pm_power_off)
1082                 pm_power_off();
1083         xen_reboot(SHUTDOWN_poweroff);
1084 }
1085 
1086 static void xen_crash_shutdown(struct pt_regs *regs)
1087 {
1088         xen_reboot(SHUTDOWN_crash);
1089 }
1090 
1091 static const struct machine_ops xen_machine_ops __initconst = {
1092         .restart = xen_restart,
1093         .halt = xen_machine_halt,
1094         .power_off = xen_machine_power_off,
1095         .shutdown = xen_machine_halt,
1096         .crash_shutdown = xen_crash_shutdown,
1097         .emergency_restart = xen_emergency_restart,
1098 };
1099 
1100 static unsigned char xen_get_nmi_reason(void)
1101 {
1102         unsigned char reason = 0;
1103 
1104         /* Construct a value which looks like it came from port 0x61. */
1105         if (test_bit(_XEN_NMIREASON_io_error,
1106                      &HYPERVISOR_shared_info->arch.nmi_reason))
1107                 reason |= NMI_REASON_IOCHK;
1108         if (test_bit(_XEN_NMIREASON_pci_serr,
1109                      &HYPERVISOR_shared_info->arch.nmi_reason))
1110                 reason |= NMI_REASON_SERR;
1111 
1112         return reason;
1113 }
1114 
1115 static void __init xen_boot_params_init_edd(void)
1116 {
1117 #if IS_ENABLED(CONFIG_EDD)
1118         struct xen_platform_op op;
1119         struct edd_info *edd_info;
1120         u32 *mbr_signature;
1121         unsigned nr;
1122         int ret;
1123 
1124         edd_info = boot_params.eddbuf;
1125         mbr_signature = boot_params.edd_mbr_sig_buffer;
1126 
1127         op.cmd = XENPF_firmware_info;
1128 
1129         op.u.firmware_info.type = XEN_FW_DISK_INFO;
1130         for (nr = 0; nr < EDDMAXNR; nr++) {
1131                 struct edd_info *info = edd_info + nr;
1132 
1133                 op.u.firmware_info.index = nr;
1134                 info->params.length = sizeof(info->params);
1135                 set_xen_guest_handle(op.u.firmware_info.u.disk_info.edd_params,
1136                                      &info->params);
1137                 ret = HYPERVISOR_platform_op(&op);
1138                 if (ret)
1139                         break;
1140 
1141 #define C(x) info->x = op.u.firmware_info.u.disk_info.x
1142                 C(device);
1143                 C(version);
1144                 C(interface_support);
1145                 C(legacy_max_cylinder);
1146                 C(legacy_max_head);
1147                 C(legacy_sectors_per_track);
1148 #undef C
1149         }
1150         boot_params.eddbuf_entries = nr;
1151 
1152         op.u.firmware_info.type = XEN_FW_DISK_MBR_SIGNATURE;
1153         for (nr = 0; nr < EDD_MBR_SIG_MAX; nr++) {
1154                 op.u.firmware_info.index = nr;
1155                 ret = HYPERVISOR_platform_op(&op);
1156                 if (ret)
1157                         break;
1158                 mbr_signature[nr] = op.u.firmware_info.u.disk_mbr_signature.mbr_signature;
1159         }
1160         boot_params.edd_mbr_sig_buf_entries = nr;
1161 #endif
1162 }
1163 
1164 /*
1165  * Set up the GDT and segment registers for -fstack-protector.  Until
1166  * we do this, we have to be careful not to call any stack-protected
1167  * function, which is most of the kernel.
1168  */
1169 static void __init xen_setup_gdt(int cpu)
1170 {
1171         pv_ops.cpu.write_gdt_entry = xen_write_gdt_entry_boot;
1172         pv_ops.cpu.load_gdt = xen_load_gdt_boot;
1173 
1174         setup_stack_canary_segment(cpu);
1175         switch_to_new_gdt(cpu);
1176 
1177         pv_ops.cpu.write_gdt_entry = xen_write_gdt_entry;
1178         pv_ops.cpu.load_gdt = xen_load_gdt;
1179 }
1180 
1181 static void __init xen_dom0_set_legacy_features(void)
1182 {
1183         x86_platform.legacy.rtc = 1;
1184 }
1185 
1186 /* First C function to be called on Xen boot */
1187 asmlinkage __visible void __init xen_start_kernel(void)
1188 {
1189         struct physdev_set_iopl set_iopl;
1190         unsigned long initrd_start = 0;
1191         int rc;
1192 
1193         if (!xen_start_info)
1194                 return;
1195 
1196         xen_domain_type = XEN_PV_DOMAIN;
1197         xen_start_flags = xen_start_info->flags;
1198 
1199         xen_setup_features();
1200 
1201         /* Install Xen paravirt ops */
1202         pv_info = xen_info;
1203         pv_ops.init.patch = paravirt_patch_default;
1204         pv_ops.cpu = xen_cpu_ops;
1205         xen_init_irq_ops();
1206 
1207         /*
1208          * Setup xen_vcpu early because it is needed for
1209          * local_irq_disable(), irqs_disabled(), e.g. in printk().
1210          *
1211          * Don't do the full vcpu_info placement stuff until we have
1212          * the cpu_possible_mask and a non-dummy shared_info.
1213          */
1214         xen_vcpu_info_reset(0);
1215 
1216         x86_platform.get_nmi_reason = xen_get_nmi_reason;
1217 
1218         x86_init.resources.memory_setup = xen_memory_setup;
1219         x86_init.irqs.intr_mode_select  = x86_init_noop;
1220         x86_init.irqs.intr_mode_init    = x86_init_noop;
1221         x86_init.oem.arch_setup = xen_arch_setup;
1222         x86_init.oem.banner = xen_banner;
1223         x86_init.hyper.init_platform = xen_pv_init_platform;
1224         x86_init.hyper.guest_late_init = xen_pv_guest_late_init;
1225 
1226         /*
1227          * Set up some pagetable state before starting to set any ptes.
1228          */
1229 
1230         xen_setup_machphys_mapping();
1231         xen_init_mmu_ops();
1232 
1233         /* Prevent unwanted bits from being set in PTEs. */
1234         __supported_pte_mask &= ~_PAGE_GLOBAL;
1235         __default_kernel_pte_mask &= ~_PAGE_GLOBAL;
1236 
1237         /*
1238          * Prevent page tables from being allocated in highmem, even
1239          * if CONFIG_HIGHPTE is enabled.
1240          */
1241         __userpte_alloc_gfp &= ~__GFP_HIGHMEM;
1242 
1243         /* Get mfn list */
1244         xen_build_dynamic_phys_to_machine();
1245 
1246         /*
1247          * Set up kernel GDT and segment registers, mainly so that
1248          * -fstack-protector code can be executed.
1249          */
1250         xen_setup_gdt(0);
1251 
1252         /* Work out if we support NX */
1253         get_cpu_cap(&boot_cpu_data);
1254         x86_configure_nx();
1255 
1256         /* Determine virtual and physical address sizes */
1257         get_cpu_address_sizes(&boot_cpu_data);
1258 
1259         /* Let's presume PV guests always boot on vCPU with id 0. */
1260         per_cpu(xen_vcpu_id, 0) = 0;
1261 
1262         idt_setup_early_handler();
1263 
1264         xen_init_capabilities();
1265 
1266 #ifdef CONFIG_X86_LOCAL_APIC
1267         /*
1268          * set up the basic apic ops.
1269          */
1270         xen_init_apic();
1271 #endif
1272 
1273         if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) {
1274                 pv_ops.mmu.ptep_modify_prot_start =
1275                         xen_ptep_modify_prot_start;
1276                 pv_ops.mmu.ptep_modify_prot_commit =
1277                         xen_ptep_modify_prot_commit;
1278         }
1279 
1280         machine_ops = xen_machine_ops;
1281 
1282         /*
1283          * The only reliable way to retain the initial address of the
1284          * percpu gdt_page is to remember it here, so we can go and
1285          * mark it RW later, when the initial percpu area is freed.
1286          */
1287         xen_initial_gdt = &per_cpu(gdt_page, 0);
1288 
1289         xen_smp_init();
1290 
1291 #ifdef CONFIG_ACPI_NUMA
1292         /*
1293          * The pages we from Xen are not related to machine pages, so
1294          * any NUMA information the kernel tries to get from ACPI will
1295          * be meaningless.  Prevent it from trying.
1296          */
1297         acpi_numa = -1;
1298 #endif
1299         WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_pv, xen_cpu_dead_pv));
1300 
1301         local_irq_disable();
1302         early_boot_irqs_disabled = true;
1303 
1304         xen_raw_console_write("mapping kernel into physical memory\n");
1305         xen_setup_kernel_pagetable((pgd_t *)xen_start_info->pt_base,
1306                                    xen_start_info->nr_pages);
1307         xen_reserve_special_pages();
1308 
1309         /* keep using Xen gdt for now; no urgent need to change it */
1310 
1311 #ifdef CONFIG_X86_32
1312         pv_info.kernel_rpl = 1;
1313         if (xen_feature(XENFEAT_supervisor_mode_kernel))
1314                 pv_info.kernel_rpl = 0;
1315 #else
1316         pv_info.kernel_rpl = 0;
1317 #endif
1318         /* set the limit of our address space */
1319         xen_reserve_top();
1320 
1321         /*
1322          * We used to do this in xen_arch_setup, but that is too late
1323          * on AMD were early_cpu_init (run before ->arch_setup()) calls
1324          * early_amd_init which pokes 0xcf8 port.
1325          */
1326         set_iopl.iopl = 1;
1327         rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
1328         if (rc != 0)
1329                 xen_raw_printk("physdev_op failed %d\n", rc);
1330 
1331 #ifdef CONFIG_X86_32
1332         /* set up basic CPUID stuff */
1333         cpu_detect(&new_cpu_data);
1334         set_cpu_cap(&new_cpu_data, X86_FEATURE_FPU);
1335         new_cpu_data.x86_capability[CPUID_1_EDX] = cpuid_edx(1);
1336 #endif
1337 
1338         if (xen_start_info->mod_start) {
1339             if (xen_start_info->flags & SIF_MOD_START_PFN)
1340                 initrd_start = PFN_PHYS(xen_start_info->mod_start);
1341             else
1342                 initrd_start = __pa(xen_start_info->mod_start);
1343         }
1344 
1345         /* Poke various useful things into boot_params */
1346         boot_params.hdr.type_of_loader = (9 << 4) | 0;
1347         boot_params.hdr.ramdisk_image = initrd_start;
1348         boot_params.hdr.ramdisk_size = xen_start_info->mod_len;
1349         boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line);
1350         boot_params.hdr.hardware_subarch = X86_SUBARCH_XEN;
1351 
1352         if (!xen_initial_domain()) {
1353                 add_preferred_console("xenboot", 0, NULL);
1354                 if (pci_xen)
1355                         x86_init.pci.arch_init = pci_xen_init;
1356         } else {
1357                 const struct dom0_vga_console_info *info =
1358                         (void *)((char *)xen_start_info +
1359                                  xen_start_info->console.dom0.info_off);
1360                 struct xen_platform_op op = {
1361                         .cmd = XENPF_firmware_info,
1362                         .interface_version = XENPF_INTERFACE_VERSION,
1363                         .u.firmware_info.type = XEN_FW_KBD_SHIFT_FLAGS,
1364                 };
1365 
1366                 x86_platform.set_legacy_features =
1367                                 xen_dom0_set_legacy_features;
1368                 xen_init_vga(info, xen_start_info->console.dom0.info_size);
1369                 xen_start_info->console.domU.mfn = 0;
1370                 xen_start_info->console.domU.evtchn = 0;
1371 
1372                 if (HYPERVISOR_platform_op(&op) == 0)
1373                         boot_params.kbd_status = op.u.firmware_info.u.kbd_shift_flags;
1374 
1375                 /* Make sure ACS will be enabled */
1376                 pci_request_acs();
1377 
1378                 xen_acpi_sleep_register();
1379 
1380                 /* Avoid searching for BIOS MP tables */
1381                 x86_init.mpparse.find_smp_config = x86_init_noop;
1382                 x86_init.mpparse.get_smp_config = x86_init_uint_noop;
1383 
1384                 xen_boot_params_init_edd();
1385         }
1386 
1387         if (!boot_params.screen_info.orig_video_isVGA)
1388                 add_preferred_console("tty", 0, NULL);
1389         add_preferred_console("hvc", 0, NULL);
1390         if (boot_params.screen_info.orig_video_isVGA)
1391                 add_preferred_console("tty", 0, NULL);
1392 
1393 #ifdef CONFIG_PCI
1394         /* PCI BIOS service won't work from a PV guest. */
1395         pci_probe &= ~PCI_PROBE_BIOS;
1396 #endif
1397         xen_raw_console_write("about to get started...\n");
1398 
1399         /* We need this for printk timestamps */
1400         xen_setup_runstate_info(0);
1401 
1402         xen_efi_init(&boot_params);
1403 
1404         /* Start the world */
1405 #ifdef CONFIG_X86_32
1406         i386_start_kernel();
1407 #else
1408         cr4_init_shadow(); /* 32b kernel does this in i386_start_kernel() */
1409         x86_64_start_reservations((char *)__pa_symbol(&boot_params));
1410 #endif
1411 }
1412 
1413 static int xen_cpu_up_prepare_pv(unsigned int cpu)
1414 {
1415         int rc;
1416 
1417         if (per_cpu(xen_vcpu, cpu) == NULL)
1418                 return -ENODEV;
1419 
1420         xen_setup_timer(cpu);
1421 
1422         rc = xen_smp_intr_init(cpu);
1423         if (rc) {
1424                 WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
1425                      cpu, rc);
1426                 return rc;
1427         }
1428 
1429         rc = xen_smp_intr_init_pv(cpu);
1430         if (rc) {
1431                 WARN(1, "xen_smp_intr_init_pv() for CPU %d failed: %d\n",
1432                      cpu, rc);
1433                 return rc;
1434         }
1435 
1436         return 0;
1437 }
1438 
1439 static int xen_cpu_dead_pv(unsigned int cpu)
1440 {
1441         xen_smp_intr_free(cpu);
1442         xen_smp_intr_free_pv(cpu);
1443 
1444         xen_teardown_timer(cpu);
1445 
1446         return 0;
1447 }
1448 
1449 static uint32_t __init xen_platform_pv(void)
1450 {
1451         if (xen_pv_domain())
1452                 return xen_cpuid_base();
1453 
1454         return 0;
1455 }
1456 
1457 const __initconst struct hypervisor_x86 x86_hyper_xen_pv = {
1458         .name                   = "Xen PV",
1459         .detect                 = xen_platform_pv,
1460         .type                   = X86_HYPER_XEN_PV,
1461         .runtime.pin_vcpu       = xen_pin_vcpu,
1462         .ignore_nopv            = true,
1463 };
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root/arch/x86/xen/enlighten_pv.c

DEFINITIONS
