1 // SPDX-License-Identifier: GPL-2.0
3 * Core of Xen paravirt_ops implementation.
5 * This file contains the xen_paravirt_ops structure itself, and the
7 * - privileged instructions
12 * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
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/bootmem.h>
27 #include <linux/export.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/memblock.h>
35 #include <linux/edd.h>
36 #include <linux/frame.h>
39 #include <xen/events.h>
40 #include <xen/interface/xen.h>
41 #include <xen/interface/version.h>
42 #include <xen/interface/physdev.h>
43 #include <xen/interface/vcpu.h>
44 #include <xen/interface/memory.h>
45 #include <xen/interface/nmi.h>
46 #include <xen/interface/xen-mca.h>
47 #include <xen/features.h>
49 #include <xen/hvc-console.h>
52 #include <asm/paravirt.h>
55 #include <asm/xen/pci.h>
56 #include <asm/xen/hypercall.h>
57 #include <asm/xen/hypervisor.h>
58 #include <asm/xen/cpuid.h>
59 #include <asm/fixmap.h>
60 #include <asm/processor.h>
61 #include <asm/proto.h>
62 #include <asm/msr-index.h>
63 #include <asm/traps.h>
64 #include <asm/setup.h>
66 #include <asm/pgalloc.h>
67 #include <asm/pgtable.h>
68 #include <asm/tlbflush.h>
69 #include <asm/reboot.h>
70 #include <asm/stackprotector.h>
71 #include <asm/hypervisor.h>
72 #include <asm/mach_traps.h>
73 #include <asm/mwait.h>
74 #include <asm/pci_x86.h>
78 #include <linux/acpi.h>
80 #include <acpi/pdc_intel.h>
81 #include <acpi/processor.h>
82 #include <xen/interface/platform.h>
88 #include "multicalls.h"
91 #include "../kernel/cpu/cpu.h" /* get_cpu_cap() */
93 void *xen_initial_gdt;
95 static int xen_cpu_up_prepare_pv(unsigned int cpu);
96 static int xen_cpu_dead_pv(unsigned int cpu);
99 struct desc_struct desc[3];
103 * Updating the 3 TLS descriptors in the GDT on every task switch is
104 * surprisingly expensive so we avoid updating them if they haven't
105 * changed. Since Xen writes different descriptors than the one
106 * passed in the update_descriptor hypercall we keep shadow copies to
109 static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc);
111 static void __init xen_banner(void)
113 unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL);
114 struct xen_extraversion extra;
115 HYPERVISOR_xen_version(XENVER_extraversion, &extra);
117 pr_info("Booting paravirtualized kernel on %s\n", pv_info.name);
118 printk(KERN_INFO "Xen version: %d.%d%s%s\n",
119 version >> 16, version & 0xffff, extra.extraversion,
120 xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : "");
123 static void __init xen_pv_init_platform(void)
125 populate_extra_pte(fix_to_virt(FIX_PARAVIRT_BOOTMAP));
127 set_fixmap(FIX_PARAVIRT_BOOTMAP, xen_start_info->shared_info);
128 HYPERVISOR_shared_info = (void *)fix_to_virt(FIX_PARAVIRT_BOOTMAP);
130 /* xen clock uses per-cpu vcpu_info, need to init it for boot cpu */
131 xen_vcpu_info_reset(0);
133 /* pvclock is in shared info area */
137 static void __init xen_pv_guest_late_init(void)
140 /* Setup shared vcpu info for non-smp configurations */
141 xen_setup_vcpu_info_placement();
145 /* Check if running on Xen version (major, minor) or later */
147 xen_running_on_version_or_later(unsigned int major, unsigned int minor)
149 unsigned int version;
154 version = HYPERVISOR_xen_version(XENVER_version, NULL);
155 if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) ||
156 ((version >> 16) > major))
161 static __read_mostly unsigned int cpuid_leaf5_ecx_val;
162 static __read_mostly unsigned int cpuid_leaf5_edx_val;
164 static void xen_cpuid(unsigned int *ax, unsigned int *bx,
165 unsigned int *cx, unsigned int *dx)
167 unsigned maskebx = ~0;
170 * Mask out inconvenient features, to try and disable as many
171 * unsupported kernel subsystems as possible.
174 case CPUID_MWAIT_LEAF:
175 /* Synthesize the values.. */
178 *cx = cpuid_leaf5_ecx_val;
179 *dx = cpuid_leaf5_edx_val;
183 /* Suppress extended topology stuff */
188 asm(XEN_EMULATE_PREFIX "cpuid"
193 : "0" (*ax), "2" (*cx));
197 STACK_FRAME_NON_STANDARD(xen_cpuid); /* XEN_EMULATE_PREFIX */
199 static bool __init xen_check_mwait(void)
202 struct xen_platform_op op = {
203 .cmd = XENPF_set_processor_pminfo,
204 .u.set_pminfo.id = -1,
205 .u.set_pminfo.type = XEN_PM_PDC,
208 unsigned int ax, bx, cx, dx;
209 unsigned int mwait_mask;
211 /* We need to determine whether it is OK to expose the MWAIT
212 * capability to the kernel to harvest deeper than C3 states from ACPI
213 * _CST using the processor_harvest_xen.c module. For this to work, we
214 * need to gather the MWAIT_LEAF values (which the cstate.c code
215 * checks against). The hypervisor won't expose the MWAIT flag because
216 * it would break backwards compatibility; so we will find out directly
217 * from the hardware and hypercall.
219 if (!xen_initial_domain())
223 * When running under platform earlier than Xen4.2, do not expose
224 * mwait, to avoid the risk of loading native acpi pad driver
226 if (!xen_running_on_version_or_later(4, 2))
232 native_cpuid(&ax, &bx, &cx, &dx);
234 mwait_mask = (1 << (X86_FEATURE_EST % 32)) |
235 (1 << (X86_FEATURE_MWAIT % 32));
237 if ((cx & mwait_mask) != mwait_mask)
240 /* We need to emulate the MWAIT_LEAF and for that we need both
241 * ecx and edx. The hypercall provides only partial information.
244 ax = CPUID_MWAIT_LEAF;
249 native_cpuid(&ax, &bx, &cx, &dx);
251 /* Ask the Hypervisor whether to clear ACPI_PDC_C_C2C3_FFH. If so,
252 * don't expose MWAIT_LEAF and let ACPI pick the IOPORT version of C3.
254 buf[0] = ACPI_PDC_REVISION_ID;
256 buf[2] = (ACPI_PDC_C_CAPABILITY_SMP | ACPI_PDC_EST_CAPABILITY_SWSMP);
258 set_xen_guest_handle(op.u.set_pminfo.pdc, buf);
260 if ((HYPERVISOR_platform_op(&op) == 0) &&
261 (buf[2] & (ACPI_PDC_C_C1_FFH | ACPI_PDC_C_C2C3_FFH))) {
262 cpuid_leaf5_ecx_val = cx;
263 cpuid_leaf5_edx_val = dx;
271 static bool __init xen_check_xsave(void)
273 unsigned int cx, xsave_mask;
277 xsave_mask = (1 << (X86_FEATURE_XSAVE % 32)) |
278 (1 << (X86_FEATURE_OSXSAVE % 32));
280 /* Xen will set CR4.OSXSAVE if supported and not disabled by force */
281 return (cx & xsave_mask) == xsave_mask;
284 static void __init xen_init_capabilities(void)
286 setup_force_cpu_cap(X86_FEATURE_XENPV);
287 setup_clear_cpu_cap(X86_FEATURE_DCA);
288 setup_clear_cpu_cap(X86_FEATURE_APERFMPERF);
289 setup_clear_cpu_cap(X86_FEATURE_MTRR);
290 setup_clear_cpu_cap(X86_FEATURE_ACC);
291 setup_clear_cpu_cap(X86_FEATURE_X2APIC);
292 setup_clear_cpu_cap(X86_FEATURE_SME);
295 * Xen PV would need some work to support PCID: CR3 handling as well
296 * as xen_flush_tlb_others() would need updating.
298 setup_clear_cpu_cap(X86_FEATURE_PCID);
300 if (!xen_initial_domain())
301 setup_clear_cpu_cap(X86_FEATURE_ACPI);
303 if (xen_check_mwait())
304 setup_force_cpu_cap(X86_FEATURE_MWAIT);
306 setup_clear_cpu_cap(X86_FEATURE_MWAIT);
308 if (!xen_check_xsave()) {
309 setup_clear_cpu_cap(X86_FEATURE_XSAVE);
310 setup_clear_cpu_cap(X86_FEATURE_OSXSAVE);
314 static void xen_set_debugreg(int reg, unsigned long val)
316 HYPERVISOR_set_debugreg(reg, val);
319 static unsigned long xen_get_debugreg(int reg)
321 return HYPERVISOR_get_debugreg(reg);
324 static void xen_end_context_switch(struct task_struct *next)
327 paravirt_end_context_switch(next);
330 static unsigned long xen_store_tr(void)
336 * Set the page permissions for a particular virtual address. If the
337 * address is a vmalloc mapping (or other non-linear mapping), then
338 * find the linear mapping of the page and also set its protections to
341 static void set_aliased_prot(void *v, pgprot_t prot)
350 ptep = lookup_address((unsigned long)v, &level);
351 BUG_ON(ptep == NULL);
353 pfn = pte_pfn(*ptep);
354 page = pfn_to_page(pfn);
356 pte = pfn_pte(pfn, prot);
359 * Careful: update_va_mapping() will fail if the virtual address
360 * we're poking isn't populated in the page tables. We don't
361 * need to worry about the direct map (that's always in the page
362 * tables), but we need to be careful about vmap space. In
363 * particular, the top level page table can lazily propagate
364 * entries between processes, so if we've switched mms since we
365 * vmapped the target in the first place, we might not have the
366 * top-level page table entry populated.
368 * We disable preemption because we want the same mm active when
369 * we probe the target and when we issue the hypercall. We'll
370 * have the same nominal mm, but if we're a kernel thread, lazy
371 * mm dropping could change our pgd.
373 * Out of an abundance of caution, this uses __get_user() to fault
374 * in the target address just in case there's some obscure case
375 * in which the target address isn't readable.
380 probe_kernel_read(&dummy, v, 1);
382 if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0))
385 if (!PageHighMem(page)) {
386 void *av = __va(PFN_PHYS(pfn));
389 if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0))
397 static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries)
399 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
403 * We need to mark the all aliases of the LDT pages RO. We
404 * don't need to call vm_flush_aliases(), though, since that's
405 * only responsible for flushing aliases out the TLBs, not the
406 * page tables, and Xen will flush the TLB for us if needed.
408 * To avoid confusing future readers: none of this is necessary
409 * to load the LDT. The hypervisor only checks this when the
410 * LDT is faulted in due to subsequent descriptor access.
413 for (i = 0; i < entries; i += entries_per_page)
414 set_aliased_prot(ldt + i, PAGE_KERNEL_RO);
417 static void xen_free_ldt(struct desc_struct *ldt, unsigned entries)
419 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
422 for (i = 0; i < entries; i += entries_per_page)
423 set_aliased_prot(ldt + i, PAGE_KERNEL);
426 static void xen_set_ldt(const void *addr, unsigned entries)
428 struct mmuext_op *op;
429 struct multicall_space mcs = xen_mc_entry(sizeof(*op));
431 trace_xen_cpu_set_ldt(addr, entries);
434 op->cmd = MMUEXT_SET_LDT;
435 op->arg1.linear_addr = (unsigned long)addr;
436 op->arg2.nr_ents = entries;
438 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
440 xen_mc_issue(PARAVIRT_LAZY_CPU);
443 static void xen_load_gdt(const struct desc_ptr *dtr)
445 unsigned long va = dtr->address;
446 unsigned int size = dtr->size + 1;
447 unsigned long pfn, mfn;
452 /* @size should be at most GDT_SIZE which is smaller than PAGE_SIZE. */
453 BUG_ON(size > PAGE_SIZE);
454 BUG_ON(va & ~PAGE_MASK);
457 * The GDT is per-cpu and is in the percpu data area.
458 * That can be virtually mapped, so we need to do a
459 * page-walk to get the underlying MFN for the
460 * hypercall. The page can also be in the kernel's
461 * linear range, so we need to RO that mapping too.
463 ptep = lookup_address(va, &level);
464 BUG_ON(ptep == NULL);
466 pfn = pte_pfn(*ptep);
467 mfn = pfn_to_mfn(pfn);
468 virt = __va(PFN_PHYS(pfn));
470 make_lowmem_page_readonly((void *)va);
471 make_lowmem_page_readonly(virt);
473 if (HYPERVISOR_set_gdt(&mfn, size / sizeof(struct desc_struct)))
478 * load_gdt for early boot, when the gdt is only mapped once
480 static void __init xen_load_gdt_boot(const struct desc_ptr *dtr)
482 unsigned long va = dtr->address;
483 unsigned int size = dtr->size + 1;
484 unsigned long pfn, mfn;
487 /* @size should be at most GDT_SIZE which is smaller than PAGE_SIZE. */
488 BUG_ON(size > PAGE_SIZE);
489 BUG_ON(va & ~PAGE_MASK);
491 pfn = virt_to_pfn(va);
492 mfn = pfn_to_mfn(pfn);
494 pte = pfn_pte(pfn, PAGE_KERNEL_RO);
496 if (HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0))
499 if (HYPERVISOR_set_gdt(&mfn, size / sizeof(struct desc_struct)))
503 static inline bool desc_equal(const struct desc_struct *d1,
504 const struct desc_struct *d2)
506 return !memcmp(d1, d2, sizeof(*d1));
509 static void load_TLS_descriptor(struct thread_struct *t,
510 unsigned int cpu, unsigned int i)
512 struct desc_struct *shadow = &per_cpu(shadow_tls_desc, cpu).desc[i];
513 struct desc_struct *gdt;
515 struct multicall_space mc;
517 if (desc_equal(shadow, &t->tls_array[i]))
520 *shadow = t->tls_array[i];
522 gdt = get_cpu_gdt_rw(cpu);
523 maddr = arbitrary_virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]);
524 mc = __xen_mc_entry(0);
526 MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]);
529 static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
532 * XXX sleazy hack: If we're being called in a lazy-cpu zone
533 * and lazy gs handling is enabled, it means we're in a
534 * context switch, and %gs has just been saved. This means we
535 * can zero it out to prevent faults on exit from the
536 * hypervisor if the next process has no %gs. Either way, it
537 * has been saved, and the new value will get loaded properly.
538 * This will go away as soon as Xen has been modified to not
539 * save/restore %gs for normal hypercalls.
541 * On x86_64, this hack is not used for %gs, because gs points
542 * to KERNEL_GS_BASE (and uses it for PDA references), so we
543 * must not zero %gs on x86_64
545 * For x86_64, we need to zero %fs, otherwise we may get an
546 * exception between the new %fs descriptor being loaded and
547 * %fs being effectively cleared at __switch_to().
549 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) {
559 load_TLS_descriptor(t, cpu, 0);
560 load_TLS_descriptor(t, cpu, 1);
561 load_TLS_descriptor(t, cpu, 2);
563 xen_mc_issue(PARAVIRT_LAZY_CPU);
567 static void xen_load_gs_index(unsigned int idx)
569 if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx))
574 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
577 xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]);
578 u64 entry = *(u64 *)ptr;
580 trace_xen_cpu_write_ldt_entry(dt, entrynum, entry);
585 if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry))
592 struct trap_array_entry {
598 static struct trap_array_entry trap_array[] = {
599 { debug, xen_xendebug, true },
600 { double_fault, xen_double_fault, true },
601 #ifdef CONFIG_X86_MCE
602 { machine_check, xen_machine_check, true },
604 { nmi, xen_xennmi, true },
605 { int3, xen_int3, false },
606 { overflow, xen_overflow, false },
607 #ifdef CONFIG_IA32_EMULATION
608 { entry_INT80_compat, xen_entry_INT80_compat, false },
610 { page_fault, xen_page_fault, false },
611 { divide_error, xen_divide_error, false },
612 { bounds, xen_bounds, false },
613 { invalid_op, xen_invalid_op, false },
614 { device_not_available, xen_device_not_available, false },
615 { coprocessor_segment_overrun, xen_coprocessor_segment_overrun, false },
616 { invalid_TSS, xen_invalid_TSS, false },
617 { segment_not_present, xen_segment_not_present, false },
618 { stack_segment, xen_stack_segment, false },
619 { general_protection, xen_general_protection, false },
620 { spurious_interrupt_bug, xen_spurious_interrupt_bug, false },
621 { coprocessor_error, xen_coprocessor_error, false },
622 { alignment_check, xen_alignment_check, false },
623 { simd_coprocessor_error, xen_simd_coprocessor_error, false },
626 static bool __ref get_trap_addr(void **addr, unsigned int ist)
629 bool ist_okay = false;
632 * Replace trap handler addresses by Xen specific ones.
633 * Check for known traps using IST and whitelist them.
634 * The debugger ones are the only ones we care about.
635 * Xen will handle faults like double_fault, * so we should never see
636 * them. Warn if there's an unexpected IST-using fault handler.
638 for (nr = 0; nr < ARRAY_SIZE(trap_array); nr++) {
639 struct trap_array_entry *entry = trap_array + nr;
641 if (*addr == entry->orig) {
643 ist_okay = entry->ist_okay;
648 if (nr == ARRAY_SIZE(trap_array) &&
649 *addr >= (void *)early_idt_handler_array[0] &&
650 *addr < (void *)early_idt_handler_array[NUM_EXCEPTION_VECTORS]) {
651 nr = (*addr - (void *)early_idt_handler_array[0]) /
652 EARLY_IDT_HANDLER_SIZE;
653 *addr = (void *)xen_early_idt_handler_array[nr];
656 if (WARN_ON(ist != 0 && !ist_okay))
663 static int cvt_gate_to_trap(int vector, const gate_desc *val,
664 struct trap_info *info)
668 if (val->bits.type != GATE_TRAP && val->bits.type != GATE_INTERRUPT)
671 info->vector = vector;
673 addr = gate_offset(val);
675 if (!get_trap_addr((void **)&addr, val->bits.ist))
677 #endif /* CONFIG_X86_64 */
678 info->address = addr;
680 info->cs = gate_segment(val);
681 info->flags = val->bits.dpl;
682 /* interrupt gates clear IF */
683 if (val->bits.type == GATE_INTERRUPT)
684 info->flags |= 1 << 2;
689 /* Locations of each CPU's IDT */
690 static DEFINE_PER_CPU(struct desc_ptr, idt_desc);
692 /* Set an IDT entry. If the entry is part of the current IDT, then
694 static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g)
696 unsigned long p = (unsigned long)&dt[entrynum];
697 unsigned long start, end;
699 trace_xen_cpu_write_idt_entry(dt, entrynum, g);
703 start = __this_cpu_read(idt_desc.address);
704 end = start + __this_cpu_read(idt_desc.size) + 1;
708 native_write_idt_entry(dt, entrynum, g);
710 if (p >= start && (p + 8) <= end) {
711 struct trap_info info[2];
715 if (cvt_gate_to_trap(entrynum, g, &info[0]))
716 if (HYPERVISOR_set_trap_table(info))
723 static unsigned xen_convert_trap_info(const struct desc_ptr *desc,
724 struct trap_info *traps, bool full)
726 unsigned in, out, count;
728 count = (desc->size+1) / sizeof(gate_desc);
731 for (in = out = 0; in < count; in++) {
732 gate_desc *entry = (gate_desc *)(desc->address) + in;
734 if (cvt_gate_to_trap(in, entry, &traps[out]) || full)
741 void xen_copy_trap_info(struct trap_info *traps)
743 const struct desc_ptr *desc = this_cpu_ptr(&idt_desc);
745 xen_convert_trap_info(desc, traps, true);
748 /* Load a new IDT into Xen. In principle this can be per-CPU, so we
749 hold a spinlock to protect the static traps[] array (static because
750 it avoids allocation, and saves stack space). */
751 static void xen_load_idt(const struct desc_ptr *desc)
753 static DEFINE_SPINLOCK(lock);
754 static struct trap_info traps[257];
757 trace_xen_cpu_load_idt(desc);
761 memcpy(this_cpu_ptr(&idt_desc), desc, sizeof(idt_desc));
763 out = xen_convert_trap_info(desc, traps, false);
764 memset(&traps[out], 0, sizeof(traps[0]));
767 if (HYPERVISOR_set_trap_table(traps))
773 /* Write a GDT descriptor entry. Ignore LDT descriptors, since
774 they're handled differently. */
775 static void xen_write_gdt_entry(struct desc_struct *dt, int entry,
776 const void *desc, int type)
778 trace_xen_cpu_write_gdt_entry(dt, entry, desc, type);
789 xmaddr_t maddr = arbitrary_virt_to_machine(&dt[entry]);
792 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
802 * Version of write_gdt_entry for use at early boot-time needed to
803 * update an entry as simply as possible.
805 static void __init xen_write_gdt_entry_boot(struct desc_struct *dt, int entry,
806 const void *desc, int type)
808 trace_xen_cpu_write_gdt_entry(dt, entry, desc, type);
817 xmaddr_t maddr = virt_to_machine(&dt[entry]);
819 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
820 dt[entry] = *(struct desc_struct *)desc;
826 static void xen_load_sp0(unsigned long sp0)
828 struct multicall_space mcs;
830 mcs = xen_mc_entry(0);
831 MULTI_stack_switch(mcs.mc, __KERNEL_DS, sp0);
832 xen_mc_issue(PARAVIRT_LAZY_CPU);
833 this_cpu_write(cpu_tss_rw.x86_tss.sp0, sp0);
836 void xen_set_iopl_mask(unsigned mask)
838 struct physdev_set_iopl set_iopl;
840 /* Force the change at ring 0. */
841 set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3;
842 HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
845 static void xen_io_delay(void)
849 static DEFINE_PER_CPU(unsigned long, xen_cr0_value);
851 static unsigned long xen_read_cr0(void)
853 unsigned long cr0 = this_cpu_read(xen_cr0_value);
855 if (unlikely(cr0 == 0)) {
856 cr0 = native_read_cr0();
857 this_cpu_write(xen_cr0_value, cr0);
863 static void xen_write_cr0(unsigned long cr0)
865 struct multicall_space mcs;
867 this_cpu_write(xen_cr0_value, cr0);
869 /* Only pay attention to cr0.TS; everything else is
871 mcs = xen_mc_entry(0);
873 MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0);
875 xen_mc_issue(PARAVIRT_LAZY_CPU);
878 static void xen_write_cr4(unsigned long cr4)
880 cr4 &= ~(X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PCE);
882 native_write_cr4(cr4);
885 static inline unsigned long xen_read_cr8(void)
889 static inline void xen_write_cr8(unsigned long val)
895 static u64 xen_read_msr_safe(unsigned int msr, int *err)
899 if (pmu_msr_read(msr, &val, err))
902 val = native_read_msr_safe(msr, err);
904 case MSR_IA32_APICBASE:
905 val &= ~X2APIC_ENABLE;
911 static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
923 case MSR_FS_BASE: which = SEGBASE_FS; goto set;
924 case MSR_KERNEL_GS_BASE: which = SEGBASE_GS_USER; goto set;
925 case MSR_GS_BASE: which = SEGBASE_GS_KERNEL; goto set;
928 base = ((u64)high << 32) | low;
929 if (HYPERVISOR_set_segment_base(which, base) != 0)
937 case MSR_SYSCALL_MASK:
938 case MSR_IA32_SYSENTER_CS:
939 case MSR_IA32_SYSENTER_ESP:
940 case MSR_IA32_SYSENTER_EIP:
941 /* Fast syscall setup is all done in hypercalls, so
942 these are all ignored. Stub them out here to stop
943 Xen console noise. */
947 if (!pmu_msr_write(msr, low, high, &ret))
948 ret = native_write_msr_safe(msr, low, high);
954 static u64 xen_read_msr(unsigned int msr)
957 * This will silently swallow a #GP from RDMSR. It may be worth
962 return xen_read_msr_safe(msr, &err);
965 static void xen_write_msr(unsigned int msr, unsigned low, unsigned high)
968 * This will silently swallow a #GP from WRMSR. It may be worth
971 xen_write_msr_safe(msr, low, high);
974 /* This is called once we have the cpu_possible_mask */
975 void __init xen_setup_vcpu_info_placement(void)
979 for_each_possible_cpu(cpu) {
980 /* Set up direct vCPU id mapping for PV guests. */
981 per_cpu(xen_vcpu_id, cpu) = cpu;
984 * xen_vcpu_setup(cpu) can fail -- in which case it
985 * falls back to the shared_info version for cpus
986 * where xen_vcpu_nr(cpu) < MAX_VIRT_CPUS.
988 * xen_cpu_up_prepare_pv() handles the rest by failing
991 (void) xen_vcpu_setup(cpu);
995 * xen_vcpu_setup managed to place the vcpu_info within the
996 * percpu area for all cpus, so make use of it.
998 if (xen_have_vcpu_info_placement) {
999 pv_irq_ops.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct);
1000 pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(xen_restore_fl_direct);
1001 pv_irq_ops.irq_disable = __PV_IS_CALLEE_SAVE(xen_irq_disable_direct);
1002 pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(xen_irq_enable_direct);
1003 pv_mmu_ops.read_cr2 = xen_read_cr2_direct;
1007 static const struct pv_info xen_info __initconst = {
1008 .shared_kernel_pmd = 0,
1010 #ifdef CONFIG_X86_64
1011 .extra_user_64bit_cs = FLAT_USER_CS64,
1016 static const struct pv_cpu_ops xen_cpu_ops __initconst = {
1019 .set_debugreg = xen_set_debugreg,
1020 .get_debugreg = xen_get_debugreg,
1022 .read_cr0 = xen_read_cr0,
1023 .write_cr0 = xen_write_cr0,
1025 .write_cr4 = xen_write_cr4,
1027 #ifdef CONFIG_X86_64
1028 .read_cr8 = xen_read_cr8,
1029 .write_cr8 = xen_write_cr8,
1032 .wbinvd = native_wbinvd,
1034 .read_msr = xen_read_msr,
1035 .write_msr = xen_write_msr,
1037 .read_msr_safe = xen_read_msr_safe,
1038 .write_msr_safe = xen_write_msr_safe,
1040 .read_pmc = xen_read_pmc,
1043 #ifdef CONFIG_X86_64
1044 .usergs_sysret64 = xen_sysret64,
1047 .load_tr_desc = paravirt_nop,
1048 .set_ldt = xen_set_ldt,
1049 .load_gdt = xen_load_gdt,
1050 .load_idt = xen_load_idt,
1051 .load_tls = xen_load_tls,
1052 #ifdef CONFIG_X86_64
1053 .load_gs_index = xen_load_gs_index,
1056 .alloc_ldt = xen_alloc_ldt,
1057 .free_ldt = xen_free_ldt,
1059 .store_tr = xen_store_tr,
1061 .write_ldt_entry = xen_write_ldt_entry,
1062 .write_gdt_entry = xen_write_gdt_entry,
1063 .write_idt_entry = xen_write_idt_entry,
1064 .load_sp0 = xen_load_sp0,
1066 .set_iopl_mask = xen_set_iopl_mask,
1067 .io_delay = xen_io_delay,
1069 /* Xen takes care of %gs when switching to usermode for us */
1070 .swapgs = paravirt_nop,
1072 .start_context_switch = paravirt_start_context_switch,
1073 .end_context_switch = xen_end_context_switch,
1076 static void xen_restart(char *msg)
1078 xen_reboot(SHUTDOWN_reboot);
1081 static void xen_machine_halt(void)
1083 xen_reboot(SHUTDOWN_poweroff);
1086 static void xen_machine_power_off(void)
1090 xen_reboot(SHUTDOWN_poweroff);
1093 static void xen_crash_shutdown(struct pt_regs *regs)
1095 xen_reboot(SHUTDOWN_crash);
1098 static const struct machine_ops xen_machine_ops __initconst = {
1099 .restart = xen_restart,
1100 .halt = xen_machine_halt,
1101 .power_off = xen_machine_power_off,
1102 .shutdown = xen_machine_halt,
1103 .crash_shutdown = xen_crash_shutdown,
1104 .emergency_restart = xen_emergency_restart,
1107 static unsigned char xen_get_nmi_reason(void)
1109 unsigned char reason = 0;
1111 /* Construct a value which looks like it came from port 0x61. */
1112 if (test_bit(_XEN_NMIREASON_io_error,
1113 &HYPERVISOR_shared_info->arch.nmi_reason))
1114 reason |= NMI_REASON_IOCHK;
1115 if (test_bit(_XEN_NMIREASON_pci_serr,
1116 &HYPERVISOR_shared_info->arch.nmi_reason))
1117 reason |= NMI_REASON_SERR;
1122 static void __init xen_boot_params_init_edd(void)
1124 #if IS_ENABLED(CONFIG_EDD)
1125 struct xen_platform_op op;
1126 struct edd_info *edd_info;
1131 edd_info = boot_params.eddbuf;
1132 mbr_signature = boot_params.edd_mbr_sig_buffer;
1134 op.cmd = XENPF_firmware_info;
1136 op.u.firmware_info.type = XEN_FW_DISK_INFO;
1137 for (nr = 0; nr < EDDMAXNR; nr++) {
1138 struct edd_info *info = edd_info + nr;
1140 op.u.firmware_info.index = nr;
1141 info->params.length = sizeof(info->params);
1142 set_xen_guest_handle(op.u.firmware_info.u.disk_info.edd_params,
1144 ret = HYPERVISOR_platform_op(&op);
1148 #define C(x) info->x = op.u.firmware_info.u.disk_info.x
1151 C(interface_support);
1152 C(legacy_max_cylinder);
1154 C(legacy_sectors_per_track);
1157 boot_params.eddbuf_entries = nr;
1159 op.u.firmware_info.type = XEN_FW_DISK_MBR_SIGNATURE;
1160 for (nr = 0; nr < EDD_MBR_SIG_MAX; nr++) {
1161 op.u.firmware_info.index = nr;
1162 ret = HYPERVISOR_platform_op(&op);
1165 mbr_signature[nr] = op.u.firmware_info.u.disk_mbr_signature.mbr_signature;
1167 boot_params.edd_mbr_sig_buf_entries = nr;
1172 * Set up the GDT and segment registers for -fstack-protector. Until
1173 * we do this, we have to be careful not to call any stack-protected
1174 * function, which is most of the kernel.
1176 static void __init xen_setup_gdt(int cpu)
1178 pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry_boot;
1179 pv_cpu_ops.load_gdt = xen_load_gdt_boot;
1181 setup_stack_canary_segment(cpu);
1182 switch_to_new_gdt(cpu);
1184 pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry;
1185 pv_cpu_ops.load_gdt = xen_load_gdt;
1188 static void __init xen_dom0_set_legacy_features(void)
1190 x86_platform.legacy.rtc = 1;
1193 static void __init xen_domu_set_legacy_features(void)
1195 x86_platform.legacy.rtc = 0;
1198 /* First C function to be called on Xen boot */
1199 asmlinkage __visible void __init xen_start_kernel(void)
1201 struct physdev_set_iopl set_iopl;
1202 unsigned long initrd_start = 0;
1205 if (!xen_start_info)
1208 xen_domain_type = XEN_PV_DOMAIN;
1209 xen_start_flags = xen_start_info->flags;
1211 xen_setup_features();
1213 /* Install Xen paravirt ops */
1215 pv_init_ops.patch = paravirt_patch_default;
1216 pv_cpu_ops = xen_cpu_ops;
1220 * Setup xen_vcpu early because it is needed for
1221 * local_irq_disable(), irqs_disabled(), e.g. in printk().
1223 * Don't do the full vcpu_info placement stuff until we have
1224 * the cpu_possible_mask and a non-dummy shared_info.
1226 xen_vcpu_info_reset(0);
1228 x86_platform.get_nmi_reason = xen_get_nmi_reason;
1230 x86_init.resources.memory_setup = xen_memory_setup;
1231 x86_init.irqs.intr_mode_init = x86_init_noop;
1232 x86_init.oem.arch_setup = xen_arch_setup;
1233 x86_init.oem.banner = xen_banner;
1234 x86_init.hyper.init_platform = xen_pv_init_platform;
1235 x86_init.hyper.guest_late_init = xen_pv_guest_late_init;
1238 * Set up some pagetable state before starting to set any ptes.
1241 xen_setup_machphys_mapping();
1244 /* Prevent unwanted bits from being set in PTEs. */
1245 __supported_pte_mask &= ~_PAGE_GLOBAL;
1246 __default_kernel_pte_mask &= ~_PAGE_GLOBAL;
1249 * Prevent page tables from being allocated in highmem, even
1250 * if CONFIG_HIGHPTE is enabled.
1252 __userpte_alloc_gfp &= ~__GFP_HIGHMEM;
1255 xen_build_dynamic_phys_to_machine();
1258 * Set up kernel GDT and segment registers, mainly so that
1259 * -fstack-protector code can be executed.
1263 /* Work out if we support NX */
1264 get_cpu_cap(&boot_cpu_data);
1267 /* Determine virtual and physical address sizes */
1268 get_cpu_address_sizes(&boot_cpu_data);
1270 /* Let's presume PV guests always boot on vCPU with id 0. */
1271 per_cpu(xen_vcpu_id, 0) = 0;
1273 idt_setup_early_handler();
1275 xen_init_capabilities();
1277 #ifdef CONFIG_X86_LOCAL_APIC
1279 * set up the basic apic ops.
1284 if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) {
1285 pv_mmu_ops.ptep_modify_prot_start = xen_ptep_modify_prot_start;
1286 pv_mmu_ops.ptep_modify_prot_commit = xen_ptep_modify_prot_commit;
1289 machine_ops = xen_machine_ops;
1292 * The only reliable way to retain the initial address of the
1293 * percpu gdt_page is to remember it here, so we can go and
1294 * mark it RW later, when the initial percpu area is freed.
1296 xen_initial_gdt = &per_cpu(gdt_page, 0);
1300 #ifdef CONFIG_ACPI_NUMA
1302 * The pages we from Xen are not related to machine pages, so
1303 * any NUMA information the kernel tries to get from ACPI will
1304 * be meaningless. Prevent it from trying.
1308 WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_pv, xen_cpu_dead_pv));
1310 local_irq_disable();
1311 early_boot_irqs_disabled = true;
1313 xen_raw_console_write("mapping kernel into physical memory\n");
1314 xen_setup_kernel_pagetable((pgd_t *)xen_start_info->pt_base,
1315 xen_start_info->nr_pages);
1316 xen_reserve_special_pages();
1318 /* keep using Xen gdt for now; no urgent need to change it */
1320 #ifdef CONFIG_X86_32
1321 pv_info.kernel_rpl = 1;
1322 if (xen_feature(XENFEAT_supervisor_mode_kernel))
1323 pv_info.kernel_rpl = 0;
1325 pv_info.kernel_rpl = 0;
1327 /* set the limit of our address space */
1331 * We used to do this in xen_arch_setup, but that is too late
1332 * on AMD were early_cpu_init (run before ->arch_setup()) calls
1333 * early_amd_init which pokes 0xcf8 port.
1336 rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
1338 xen_raw_printk("physdev_op failed %d\n", rc);
1340 #ifdef CONFIG_X86_32
1341 /* set up basic CPUID stuff */
1342 cpu_detect(&new_cpu_data);
1343 set_cpu_cap(&new_cpu_data, X86_FEATURE_FPU);
1344 new_cpu_data.x86_capability[CPUID_1_EDX] = cpuid_edx(1);
1347 if (xen_start_info->mod_start) {
1348 if (xen_start_info->flags & SIF_MOD_START_PFN)
1349 initrd_start = PFN_PHYS(xen_start_info->mod_start);
1351 initrd_start = __pa(xen_start_info->mod_start);
1354 /* Poke various useful things into boot_params */
1355 boot_params.hdr.type_of_loader = (9 << 4) | 0;
1356 boot_params.hdr.ramdisk_image = initrd_start;
1357 boot_params.hdr.ramdisk_size = xen_start_info->mod_len;
1358 boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line);
1359 boot_params.hdr.hardware_subarch = X86_SUBARCH_XEN;
1361 if (!xen_initial_domain()) {
1362 add_preferred_console("xenboot", 0, NULL);
1364 x86_init.pci.arch_init = pci_xen_init;
1365 x86_platform.set_legacy_features =
1366 xen_domu_set_legacy_features;
1368 const struct dom0_vga_console_info *info =
1369 (void *)((char *)xen_start_info +
1370 xen_start_info->console.dom0.info_off);
1371 struct xen_platform_op op = {
1372 .cmd = XENPF_firmware_info,
1373 .interface_version = XENPF_INTERFACE_VERSION,
1374 .u.firmware_info.type = XEN_FW_KBD_SHIFT_FLAGS,
1377 x86_platform.set_legacy_features =
1378 xen_dom0_set_legacy_features;
1379 xen_init_vga(info, xen_start_info->console.dom0.info_size);
1380 xen_start_info->console.domU.mfn = 0;
1381 xen_start_info->console.domU.evtchn = 0;
1383 if (HYPERVISOR_platform_op(&op) == 0)
1384 boot_params.kbd_status = op.u.firmware_info.u.kbd_shift_flags;
1386 /* Make sure ACS will be enabled */
1389 xen_acpi_sleep_register();
1391 /* Avoid searching for BIOS MP tables */
1392 x86_init.mpparse.find_smp_config = x86_init_noop;
1393 x86_init.mpparse.get_smp_config = x86_init_uint_noop;
1395 xen_boot_params_init_edd();
1399 * Disable selecting "Firmware First mode" for correctable
1400 * memory errors, as this is the duty of the hypervisor to
1403 acpi_disable_cmcff = 1;
1407 if (!boot_params.screen_info.orig_video_isVGA)
1408 add_preferred_console("tty", 0, NULL);
1409 add_preferred_console("hvc", 0, NULL);
1410 if (boot_params.screen_info.orig_video_isVGA)
1411 add_preferred_console("tty", 0, NULL);
1414 /* PCI BIOS service won't work from a PV guest. */
1415 pci_probe &= ~PCI_PROBE_BIOS;
1417 xen_raw_console_write("about to get started...\n");
1419 /* We need this for printk timestamps */
1420 xen_setup_runstate_info(0);
1422 xen_efi_init(&boot_params);
1424 /* Start the world */
1425 #ifdef CONFIG_X86_32
1426 i386_start_kernel();
1428 cr4_init_shadow(); /* 32b kernel does this in i386_start_kernel() */
1429 x86_64_start_reservations((char *)__pa_symbol(&boot_params));
1433 static int xen_cpu_up_prepare_pv(unsigned int cpu)
1437 if (per_cpu(xen_vcpu, cpu) == NULL)
1440 xen_setup_timer(cpu);
1442 rc = xen_smp_intr_init(cpu);
1444 WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
1449 rc = xen_smp_intr_init_pv(cpu);
1451 WARN(1, "xen_smp_intr_init_pv() for CPU %d failed: %d\n",
1459 static int xen_cpu_dead_pv(unsigned int cpu)
1461 xen_smp_intr_free(cpu);
1462 xen_smp_intr_free_pv(cpu);
1464 xen_teardown_timer(cpu);
1469 static uint32_t __init xen_platform_pv(void)
1471 if (xen_pv_domain())
1472 return xen_cpuid_base();
1477 const __initconst struct hypervisor_x86 x86_hyper_xen_pv = {
1479 .detect = xen_platform_pv,
1480 .type = X86_HYPER_XEN_PV,
1481 .runtime.pin_vcpu = xen_pin_vcpu,