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 void *xen_initial_gdt;
93 static int xen_cpu_up_prepare_pv(unsigned int cpu);
94 static int xen_cpu_dead_pv(unsigned int cpu);
97 struct desc_struct desc[3];
101 * Updating the 3 TLS descriptors in the GDT on every task switch is
102 * surprisingly expensive so we avoid updating them if they haven't
103 * changed. Since Xen writes different descriptors than the one
104 * passed in the update_descriptor hypercall we keep shadow copies to
107 static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc);
109 static void __init xen_banner(void)
111 unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL);
112 struct xen_extraversion extra;
113 HYPERVISOR_xen_version(XENVER_extraversion, &extra);
115 pr_info("Booting paravirtualized kernel on %s\n", pv_info.name);
116 printk(KERN_INFO "Xen version: %d.%d%s%s\n",
117 version >> 16, version & 0xffff, extra.extraversion,
118 xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : "");
120 /* Check if running on Xen version (major, minor) or later */
122 xen_running_on_version_or_later(unsigned int major, unsigned int minor)
124 unsigned int version;
129 version = HYPERVISOR_xen_version(XENVER_version, NULL);
130 if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) ||
131 ((version >> 16) > major))
136 static __read_mostly unsigned int cpuid_leaf5_ecx_val;
137 static __read_mostly unsigned int cpuid_leaf5_edx_val;
139 static void xen_cpuid(unsigned int *ax, unsigned int *bx,
140 unsigned int *cx, unsigned int *dx)
142 unsigned maskebx = ~0;
145 * Mask out inconvenient features, to try and disable as many
146 * unsupported kernel subsystems as possible.
149 case CPUID_MWAIT_LEAF:
150 /* Synthesize the values.. */
153 *cx = cpuid_leaf5_ecx_val;
154 *dx = cpuid_leaf5_edx_val;
158 /* Suppress extended topology stuff */
163 asm(XEN_EMULATE_PREFIX "cpuid"
168 : "0" (*ax), "2" (*cx));
172 STACK_FRAME_NON_STANDARD(xen_cpuid); /* XEN_EMULATE_PREFIX */
174 static bool __init xen_check_mwait(void)
177 struct xen_platform_op op = {
178 .cmd = XENPF_set_processor_pminfo,
179 .u.set_pminfo.id = -1,
180 .u.set_pminfo.type = XEN_PM_PDC,
183 unsigned int ax, bx, cx, dx;
184 unsigned int mwait_mask;
186 /* We need to determine whether it is OK to expose the MWAIT
187 * capability to the kernel to harvest deeper than C3 states from ACPI
188 * _CST using the processor_harvest_xen.c module. For this to work, we
189 * need to gather the MWAIT_LEAF values (which the cstate.c code
190 * checks against). The hypervisor won't expose the MWAIT flag because
191 * it would break backwards compatibility; so we will find out directly
192 * from the hardware and hypercall.
194 if (!xen_initial_domain())
198 * When running under platform earlier than Xen4.2, do not expose
199 * mwait, to avoid the risk of loading native acpi pad driver
201 if (!xen_running_on_version_or_later(4, 2))
207 native_cpuid(&ax, &bx, &cx, &dx);
209 mwait_mask = (1 << (X86_FEATURE_EST % 32)) |
210 (1 << (X86_FEATURE_MWAIT % 32));
212 if ((cx & mwait_mask) != mwait_mask)
215 /* We need to emulate the MWAIT_LEAF and for that we need both
216 * ecx and edx. The hypercall provides only partial information.
219 ax = CPUID_MWAIT_LEAF;
224 native_cpuid(&ax, &bx, &cx, &dx);
226 /* Ask the Hypervisor whether to clear ACPI_PDC_C_C2C3_FFH. If so,
227 * don't expose MWAIT_LEAF and let ACPI pick the IOPORT version of C3.
229 buf[0] = ACPI_PDC_REVISION_ID;
231 buf[2] = (ACPI_PDC_C_CAPABILITY_SMP | ACPI_PDC_EST_CAPABILITY_SWSMP);
233 set_xen_guest_handle(op.u.set_pminfo.pdc, buf);
235 if ((HYPERVISOR_platform_op(&op) == 0) &&
236 (buf[2] & (ACPI_PDC_C_C1_FFH | ACPI_PDC_C_C2C3_FFH))) {
237 cpuid_leaf5_ecx_val = cx;
238 cpuid_leaf5_edx_val = dx;
246 static bool __init xen_check_xsave(void)
248 unsigned int cx, xsave_mask;
252 xsave_mask = (1 << (X86_FEATURE_XSAVE % 32)) |
253 (1 << (X86_FEATURE_OSXSAVE % 32));
255 /* Xen will set CR4.OSXSAVE if supported and not disabled by force */
256 return (cx & xsave_mask) == xsave_mask;
259 static void __init xen_init_capabilities(void)
261 setup_force_cpu_cap(X86_FEATURE_XENPV);
262 setup_clear_cpu_cap(X86_FEATURE_DCA);
263 setup_clear_cpu_cap(X86_FEATURE_APERFMPERF);
264 setup_clear_cpu_cap(X86_FEATURE_MTRR);
265 setup_clear_cpu_cap(X86_FEATURE_ACC);
266 setup_clear_cpu_cap(X86_FEATURE_X2APIC);
267 setup_clear_cpu_cap(X86_FEATURE_SME);
270 * Xen PV would need some work to support PCID: CR3 handling as well
271 * as xen_flush_tlb_others() would need updating.
273 setup_clear_cpu_cap(X86_FEATURE_PCID);
275 if (!xen_initial_domain())
276 setup_clear_cpu_cap(X86_FEATURE_ACPI);
278 if (xen_check_mwait())
279 setup_force_cpu_cap(X86_FEATURE_MWAIT);
281 setup_clear_cpu_cap(X86_FEATURE_MWAIT);
283 if (!xen_check_xsave()) {
284 setup_clear_cpu_cap(X86_FEATURE_XSAVE);
285 setup_clear_cpu_cap(X86_FEATURE_OSXSAVE);
289 static void xen_set_debugreg(int reg, unsigned long val)
291 HYPERVISOR_set_debugreg(reg, val);
294 static unsigned long xen_get_debugreg(int reg)
296 return HYPERVISOR_get_debugreg(reg);
299 static void xen_end_context_switch(struct task_struct *next)
302 paravirt_end_context_switch(next);
305 static unsigned long xen_store_tr(void)
311 * Set the page permissions for a particular virtual address. If the
312 * address is a vmalloc mapping (or other non-linear mapping), then
313 * find the linear mapping of the page and also set its protections to
316 static void set_aliased_prot(void *v, pgprot_t prot)
325 ptep = lookup_address((unsigned long)v, &level);
326 BUG_ON(ptep == NULL);
328 pfn = pte_pfn(*ptep);
329 page = pfn_to_page(pfn);
331 pte = pfn_pte(pfn, prot);
334 * Careful: update_va_mapping() will fail if the virtual address
335 * we're poking isn't populated in the page tables. We don't
336 * need to worry about the direct map (that's always in the page
337 * tables), but we need to be careful about vmap space. In
338 * particular, the top level page table can lazily propagate
339 * entries between processes, so if we've switched mms since we
340 * vmapped the target in the first place, we might not have the
341 * top-level page table entry populated.
343 * We disable preemption because we want the same mm active when
344 * we probe the target and when we issue the hypercall. We'll
345 * have the same nominal mm, but if we're a kernel thread, lazy
346 * mm dropping could change our pgd.
348 * Out of an abundance of caution, this uses __get_user() to fault
349 * in the target address just in case there's some obscure case
350 * in which the target address isn't readable.
355 probe_kernel_read(&dummy, v, 1);
357 if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0))
360 if (!PageHighMem(page)) {
361 void *av = __va(PFN_PHYS(pfn));
364 if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0))
372 static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries)
374 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
378 * We need to mark the all aliases of the LDT pages RO. We
379 * don't need to call vm_flush_aliases(), though, since that's
380 * only responsible for flushing aliases out the TLBs, not the
381 * page tables, and Xen will flush the TLB for us if needed.
383 * To avoid confusing future readers: none of this is necessary
384 * to load the LDT. The hypervisor only checks this when the
385 * LDT is faulted in due to subsequent descriptor access.
388 for (i = 0; i < entries; i += entries_per_page)
389 set_aliased_prot(ldt + i, PAGE_KERNEL_RO);
392 static void xen_free_ldt(struct desc_struct *ldt, unsigned entries)
394 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
397 for (i = 0; i < entries; i += entries_per_page)
398 set_aliased_prot(ldt + i, PAGE_KERNEL);
401 static void xen_set_ldt(const void *addr, unsigned entries)
403 struct mmuext_op *op;
404 struct multicall_space mcs = xen_mc_entry(sizeof(*op));
406 trace_xen_cpu_set_ldt(addr, entries);
409 op->cmd = MMUEXT_SET_LDT;
410 op->arg1.linear_addr = (unsigned long)addr;
411 op->arg2.nr_ents = entries;
413 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
415 xen_mc_issue(PARAVIRT_LAZY_CPU);
418 static void xen_load_gdt(const struct desc_ptr *dtr)
420 unsigned long va = dtr->address;
421 unsigned int size = dtr->size + 1;
422 unsigned pages = DIV_ROUND_UP(size, PAGE_SIZE);
423 unsigned long frames[pages];
427 * A GDT can be up to 64k in size, which corresponds to 8192
428 * 8-byte entries, or 16 4k pages..
431 BUG_ON(size > 65536);
432 BUG_ON(va & ~PAGE_MASK);
434 for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) {
437 unsigned long pfn, mfn;
441 * The GDT is per-cpu and is in the percpu data area.
442 * That can be virtually mapped, so we need to do a
443 * page-walk to get the underlying MFN for the
444 * hypercall. The page can also be in the kernel's
445 * linear range, so we need to RO that mapping too.
447 ptep = lookup_address(va, &level);
448 BUG_ON(ptep == NULL);
450 pfn = pte_pfn(*ptep);
451 mfn = pfn_to_mfn(pfn);
452 virt = __va(PFN_PHYS(pfn));
456 make_lowmem_page_readonly((void *)va);
457 make_lowmem_page_readonly(virt);
460 if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct)))
465 * load_gdt for early boot, when the gdt is only mapped once
467 static void __init xen_load_gdt_boot(const struct desc_ptr *dtr)
469 unsigned long va = dtr->address;
470 unsigned int size = dtr->size + 1;
471 unsigned pages = DIV_ROUND_UP(size, PAGE_SIZE);
472 unsigned long frames[pages];
476 * A GDT can be up to 64k in size, which corresponds to 8192
477 * 8-byte entries, or 16 4k pages..
480 BUG_ON(size > 65536);
481 BUG_ON(va & ~PAGE_MASK);
483 for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) {
485 unsigned long pfn, mfn;
487 pfn = virt_to_pfn(va);
488 mfn = pfn_to_mfn(pfn);
490 pte = pfn_pte(pfn, PAGE_KERNEL_RO);
492 if (HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0))
498 if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct)))
502 static inline bool desc_equal(const struct desc_struct *d1,
503 const struct desc_struct *d2)
505 return !memcmp(d1, d2, sizeof(*d1));
508 static void load_TLS_descriptor(struct thread_struct *t,
509 unsigned int cpu, unsigned int i)
511 struct desc_struct *shadow = &per_cpu(shadow_tls_desc, cpu).desc[i];
512 struct desc_struct *gdt;
514 struct multicall_space mc;
516 if (desc_equal(shadow, &t->tls_array[i]))
519 *shadow = t->tls_array[i];
521 gdt = get_cpu_gdt_rw(cpu);
522 maddr = arbitrary_virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]);
523 mc = __xen_mc_entry(0);
525 MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]);
528 static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
531 * XXX sleazy hack: If we're being called in a lazy-cpu zone
532 * and lazy gs handling is enabled, it means we're in a
533 * context switch, and %gs has just been saved. This means we
534 * can zero it out to prevent faults on exit from the
535 * hypervisor if the next process has no %gs. Either way, it
536 * has been saved, and the new value will get loaded properly.
537 * This will go away as soon as Xen has been modified to not
538 * save/restore %gs for normal hypercalls.
540 * On x86_64, this hack is not used for %gs, because gs points
541 * to KERNEL_GS_BASE (and uses it for PDA references), so we
542 * must not zero %gs on x86_64
544 * For x86_64, we need to zero %fs, otherwise we may get an
545 * exception between the new %fs descriptor being loaded and
546 * %fs being effectively cleared at __switch_to().
548 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) {
558 load_TLS_descriptor(t, cpu, 0);
559 load_TLS_descriptor(t, cpu, 1);
560 load_TLS_descriptor(t, cpu, 2);
562 xen_mc_issue(PARAVIRT_LAZY_CPU);
566 static void xen_load_gs_index(unsigned int idx)
568 if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx))
573 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
576 xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]);
577 u64 entry = *(u64 *)ptr;
579 trace_xen_cpu_write_ldt_entry(dt, entrynum, entry);
584 if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry))
591 struct trap_array_entry {
597 static struct trap_array_entry trap_array[] = {
598 { debug, xen_xendebug, true },
599 { int3, xen_xenint3, true },
600 { double_fault, xen_double_fault, true },
601 #ifdef CONFIG_X86_MCE
602 { machine_check, xen_machine_check, true },
604 { nmi, xen_nmi, true },
605 { overflow, xen_overflow, false },
606 #ifdef CONFIG_IA32_EMULATION
607 { entry_INT80_compat, xen_entry_INT80_compat, false },
609 { page_fault, xen_page_fault, false },
610 { divide_error, xen_divide_error, false },
611 { bounds, xen_bounds, false },
612 { invalid_op, xen_invalid_op, false },
613 { device_not_available, xen_device_not_available, false },
614 { coprocessor_segment_overrun, xen_coprocessor_segment_overrun, false },
615 { invalid_TSS, xen_invalid_TSS, false },
616 { segment_not_present, xen_segment_not_present, false },
617 { stack_segment, xen_stack_segment, false },
618 { general_protection, xen_general_protection, false },
619 { spurious_interrupt_bug, xen_spurious_interrupt_bug, false },
620 { coprocessor_error, xen_coprocessor_error, false },
621 { alignment_check, xen_alignment_check, false },
622 { simd_coprocessor_error, xen_simd_coprocessor_error, false },
625 static bool get_trap_addr(void **addr, unsigned int ist)
628 bool ist_okay = false;
631 * Replace trap handler addresses by Xen specific ones.
632 * Check for known traps using IST and whitelist them.
633 * The debugger ones are the only ones we care about.
634 * Xen will handle faults like double_fault, * so we should never see
635 * them. Warn if there's an unexpected IST-using fault handler.
637 for (nr = 0; nr < ARRAY_SIZE(trap_array); nr++) {
638 struct trap_array_entry *entry = trap_array + nr;
640 if (*addr == entry->orig) {
642 ist_okay = entry->ist_okay;
647 if (WARN_ON(ist != 0 && !ist_okay))
654 static int cvt_gate_to_trap(int vector, const gate_desc *val,
655 struct trap_info *info)
659 if (val->bits.type != GATE_TRAP && val->bits.type != GATE_INTERRUPT)
662 info->vector = vector;
664 addr = gate_offset(val);
666 if (!get_trap_addr((void **)&addr, val->bits.ist))
668 #endif /* CONFIG_X86_64 */
669 info->address = addr;
671 info->cs = gate_segment(val);
672 info->flags = val->bits.dpl;
673 /* interrupt gates clear IF */
674 if (val->bits.type == GATE_INTERRUPT)
675 info->flags |= 1 << 2;
680 /* Locations of each CPU's IDT */
681 static DEFINE_PER_CPU(struct desc_ptr, idt_desc);
683 /* Set an IDT entry. If the entry is part of the current IDT, then
685 static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g)
687 unsigned long p = (unsigned long)&dt[entrynum];
688 unsigned long start, end;
690 trace_xen_cpu_write_idt_entry(dt, entrynum, g);
694 start = __this_cpu_read(idt_desc.address);
695 end = start + __this_cpu_read(idt_desc.size) + 1;
699 native_write_idt_entry(dt, entrynum, g);
701 if (p >= start && (p + 8) <= end) {
702 struct trap_info info[2];
706 if (cvt_gate_to_trap(entrynum, g, &info[0]))
707 if (HYPERVISOR_set_trap_table(info))
714 static void xen_convert_trap_info(const struct desc_ptr *desc,
715 struct trap_info *traps)
717 unsigned in, out, count;
719 count = (desc->size+1) / sizeof(gate_desc);
722 for (in = out = 0; in < count; in++) {
723 gate_desc *entry = (gate_desc *)(desc->address) + in;
725 if (cvt_gate_to_trap(in, entry, &traps[out]))
728 traps[out].address = 0;
731 void xen_copy_trap_info(struct trap_info *traps)
733 const struct desc_ptr *desc = this_cpu_ptr(&idt_desc);
735 xen_convert_trap_info(desc, traps);
738 /* Load a new IDT into Xen. In principle this can be per-CPU, so we
739 hold a spinlock to protect the static traps[] array (static because
740 it avoids allocation, and saves stack space). */
741 static void xen_load_idt(const struct desc_ptr *desc)
743 static DEFINE_SPINLOCK(lock);
744 static struct trap_info traps[257];
746 trace_xen_cpu_load_idt(desc);
750 memcpy(this_cpu_ptr(&idt_desc), desc, sizeof(idt_desc));
752 xen_convert_trap_info(desc, traps);
755 if (HYPERVISOR_set_trap_table(traps))
761 /* Write a GDT descriptor entry. Ignore LDT descriptors, since
762 they're handled differently. */
763 static void xen_write_gdt_entry(struct desc_struct *dt, int entry,
764 const void *desc, int type)
766 trace_xen_cpu_write_gdt_entry(dt, entry, desc, type);
777 xmaddr_t maddr = arbitrary_virt_to_machine(&dt[entry]);
780 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
790 * Version of write_gdt_entry for use at early boot-time needed to
791 * update an entry as simply as possible.
793 static void __init xen_write_gdt_entry_boot(struct desc_struct *dt, int entry,
794 const void *desc, int type)
796 trace_xen_cpu_write_gdt_entry(dt, entry, desc, type);
805 xmaddr_t maddr = virt_to_machine(&dt[entry]);
807 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
808 dt[entry] = *(struct desc_struct *)desc;
814 static void xen_load_sp0(struct tss_struct *tss,
815 struct thread_struct *thread)
817 struct multicall_space mcs;
819 mcs = xen_mc_entry(0);
820 MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->sp0);
821 xen_mc_issue(PARAVIRT_LAZY_CPU);
822 tss->x86_tss.sp0 = thread->sp0;
825 void xen_set_iopl_mask(unsigned mask)
827 struct physdev_set_iopl set_iopl;
829 /* Force the change at ring 0. */
830 set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3;
831 HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
834 static void xen_io_delay(void)
838 static DEFINE_PER_CPU(unsigned long, xen_cr0_value);
840 static unsigned long xen_read_cr0(void)
842 unsigned long cr0 = this_cpu_read(xen_cr0_value);
844 if (unlikely(cr0 == 0)) {
845 cr0 = native_read_cr0();
846 this_cpu_write(xen_cr0_value, cr0);
852 static void xen_write_cr0(unsigned long cr0)
854 struct multicall_space mcs;
856 this_cpu_write(xen_cr0_value, cr0);
858 /* Only pay attention to cr0.TS; everything else is
860 mcs = xen_mc_entry(0);
862 MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0);
864 xen_mc_issue(PARAVIRT_LAZY_CPU);
867 static void xen_write_cr4(unsigned long cr4)
869 cr4 &= ~(X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PCE);
871 native_write_cr4(cr4);
874 static inline unsigned long xen_read_cr8(void)
878 static inline void xen_write_cr8(unsigned long val)
884 static u64 xen_read_msr_safe(unsigned int msr, int *err)
888 if (pmu_msr_read(msr, &val, err))
891 val = native_read_msr_safe(msr, err);
893 case MSR_IA32_APICBASE:
894 #ifdef CONFIG_X86_X2APIC
895 if (!(cpuid_ecx(1) & (1 << (X86_FEATURE_X2APIC & 31))))
897 val &= ~X2APIC_ENABLE;
903 static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
914 case MSR_FS_BASE: which = SEGBASE_FS; goto set;
915 case MSR_KERNEL_GS_BASE: which = SEGBASE_GS_USER; goto set;
916 case MSR_GS_BASE: which = SEGBASE_GS_KERNEL; goto set;
919 base = ((u64)high << 32) | low;
920 if (HYPERVISOR_set_segment_base(which, base) != 0)
928 case MSR_SYSCALL_MASK:
929 case MSR_IA32_SYSENTER_CS:
930 case MSR_IA32_SYSENTER_ESP:
931 case MSR_IA32_SYSENTER_EIP:
932 /* Fast syscall setup is all done in hypercalls, so
933 these are all ignored. Stub them out here to stop
934 Xen console noise. */
938 if (!pmu_msr_write(msr, low, high, &ret))
939 ret = native_write_msr_safe(msr, low, high);
945 static u64 xen_read_msr(unsigned int msr)
948 * This will silently swallow a #GP from RDMSR. It may be worth
953 return xen_read_msr_safe(msr, &err);
956 static void xen_write_msr(unsigned int msr, unsigned low, unsigned high)
959 * This will silently swallow a #GP from WRMSR. It may be worth
962 xen_write_msr_safe(msr, low, high);
965 void xen_setup_shared_info(void)
967 set_fixmap(FIX_PARAVIRT_BOOTMAP, xen_start_info->shared_info);
969 HYPERVISOR_shared_info =
970 (struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP);
972 xen_setup_mfn_list_list();
974 if (system_state == SYSTEM_BOOTING) {
977 * In UP this is as good a place as any to set up shared info.
978 * Limit this to boot only, at restore vcpu setup is done via
979 * xen_vcpu_restore().
981 xen_setup_vcpu_info_placement();
984 * Now that shared info is set up we can start using routines
985 * that point to pvclock area.
991 /* This is called once we have the cpu_possible_mask */
992 void __ref xen_setup_vcpu_info_placement(void)
996 for_each_possible_cpu(cpu) {
997 /* Set up direct vCPU id mapping for PV guests. */
998 per_cpu(xen_vcpu_id, cpu) = cpu;
1001 * xen_vcpu_setup(cpu) can fail -- in which case it
1002 * falls back to the shared_info version for cpus
1003 * where xen_vcpu_nr(cpu) < MAX_VIRT_CPUS.
1005 * xen_cpu_up_prepare_pv() handles the rest by failing
1008 (void) xen_vcpu_setup(cpu);
1012 * xen_vcpu_setup managed to place the vcpu_info within the
1013 * percpu area for all cpus, so make use of it.
1015 if (xen_have_vcpu_info_placement) {
1016 pv_irq_ops.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct);
1017 pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(xen_restore_fl_direct);
1018 pv_irq_ops.irq_disable = __PV_IS_CALLEE_SAVE(xen_irq_disable_direct);
1019 pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(xen_irq_enable_direct);
1020 pv_mmu_ops.read_cr2 = xen_read_cr2_direct;
1024 static const struct pv_info xen_info __initconst = {
1025 .shared_kernel_pmd = 0,
1027 #ifdef CONFIG_X86_64
1028 .extra_user_64bit_cs = FLAT_USER_CS64,
1033 static const struct pv_cpu_ops xen_cpu_ops __initconst = {
1036 .set_debugreg = xen_set_debugreg,
1037 .get_debugreg = xen_get_debugreg,
1039 .read_cr0 = xen_read_cr0,
1040 .write_cr0 = xen_write_cr0,
1042 .write_cr4 = xen_write_cr4,
1044 #ifdef CONFIG_X86_64
1045 .read_cr8 = xen_read_cr8,
1046 .write_cr8 = xen_write_cr8,
1049 .wbinvd = native_wbinvd,
1051 .read_msr = xen_read_msr,
1052 .write_msr = xen_write_msr,
1054 .read_msr_safe = xen_read_msr_safe,
1055 .write_msr_safe = xen_write_msr_safe,
1057 .read_pmc = xen_read_pmc,
1060 #ifdef CONFIG_X86_64
1061 .usergs_sysret64 = xen_sysret64,
1064 .load_tr_desc = paravirt_nop,
1065 .set_ldt = xen_set_ldt,
1066 .load_gdt = xen_load_gdt,
1067 .load_idt = xen_load_idt,
1068 .load_tls = xen_load_tls,
1069 #ifdef CONFIG_X86_64
1070 .load_gs_index = xen_load_gs_index,
1073 .alloc_ldt = xen_alloc_ldt,
1074 .free_ldt = xen_free_ldt,
1076 .store_tr = xen_store_tr,
1078 .write_ldt_entry = xen_write_ldt_entry,
1079 .write_gdt_entry = xen_write_gdt_entry,
1080 .write_idt_entry = xen_write_idt_entry,
1081 .load_sp0 = xen_load_sp0,
1083 .set_iopl_mask = xen_set_iopl_mask,
1084 .io_delay = xen_io_delay,
1086 /* Xen takes care of %gs when switching to usermode for us */
1087 .swapgs = paravirt_nop,
1089 .start_context_switch = paravirt_start_context_switch,
1090 .end_context_switch = xen_end_context_switch,
1093 static void xen_restart(char *msg)
1095 xen_reboot(SHUTDOWN_reboot);
1098 static void xen_machine_halt(void)
1100 xen_reboot(SHUTDOWN_poweroff);
1103 static void xen_machine_power_off(void)
1107 xen_reboot(SHUTDOWN_poweroff);
1110 static void xen_crash_shutdown(struct pt_regs *regs)
1112 xen_reboot(SHUTDOWN_crash);
1115 static const struct machine_ops xen_machine_ops __initconst = {
1116 .restart = xen_restart,
1117 .halt = xen_machine_halt,
1118 .power_off = xen_machine_power_off,
1119 .shutdown = xen_machine_halt,
1120 .crash_shutdown = xen_crash_shutdown,
1121 .emergency_restart = xen_emergency_restart,
1124 static unsigned char xen_get_nmi_reason(void)
1126 unsigned char reason = 0;
1128 /* Construct a value which looks like it came from port 0x61. */
1129 if (test_bit(_XEN_NMIREASON_io_error,
1130 &HYPERVISOR_shared_info->arch.nmi_reason))
1131 reason |= NMI_REASON_IOCHK;
1132 if (test_bit(_XEN_NMIREASON_pci_serr,
1133 &HYPERVISOR_shared_info->arch.nmi_reason))
1134 reason |= NMI_REASON_SERR;
1139 static void __init xen_boot_params_init_edd(void)
1141 #if IS_ENABLED(CONFIG_EDD)
1142 struct xen_platform_op op;
1143 struct edd_info *edd_info;
1148 edd_info = boot_params.eddbuf;
1149 mbr_signature = boot_params.edd_mbr_sig_buffer;
1151 op.cmd = XENPF_firmware_info;
1153 op.u.firmware_info.type = XEN_FW_DISK_INFO;
1154 for (nr = 0; nr < EDDMAXNR; nr++) {
1155 struct edd_info *info = edd_info + nr;
1157 op.u.firmware_info.index = nr;
1158 info->params.length = sizeof(info->params);
1159 set_xen_guest_handle(op.u.firmware_info.u.disk_info.edd_params,
1161 ret = HYPERVISOR_platform_op(&op);
1165 #define C(x) info->x = op.u.firmware_info.u.disk_info.x
1168 C(interface_support);
1169 C(legacy_max_cylinder);
1171 C(legacy_sectors_per_track);
1174 boot_params.eddbuf_entries = nr;
1176 op.u.firmware_info.type = XEN_FW_DISK_MBR_SIGNATURE;
1177 for (nr = 0; nr < EDD_MBR_SIG_MAX; nr++) {
1178 op.u.firmware_info.index = nr;
1179 ret = HYPERVISOR_platform_op(&op);
1182 mbr_signature[nr] = op.u.firmware_info.u.disk_mbr_signature.mbr_signature;
1184 boot_params.edd_mbr_sig_buf_entries = nr;
1189 * Set up the GDT and segment registers for -fstack-protector. Until
1190 * we do this, we have to be careful not to call any stack-protected
1191 * function, which is most of the kernel.
1193 static void xen_setup_gdt(int cpu)
1195 pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry_boot;
1196 pv_cpu_ops.load_gdt = xen_load_gdt_boot;
1198 setup_stack_canary_segment(0);
1199 switch_to_new_gdt(0);
1201 pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry;
1202 pv_cpu_ops.load_gdt = xen_load_gdt;
1205 static void __init xen_dom0_set_legacy_features(void)
1207 x86_platform.legacy.rtc = 1;
1210 /* First C function to be called on Xen boot */
1211 asmlinkage __visible void __init xen_start_kernel(void)
1213 struct physdev_set_iopl set_iopl;
1214 unsigned long initrd_start = 0;
1217 if (!xen_start_info)
1220 xen_domain_type = XEN_PV_DOMAIN;
1222 xen_setup_features();
1224 xen_setup_machphys_mapping();
1226 /* Install Xen paravirt ops */
1228 pv_init_ops.patch = paravirt_patch_default;
1229 pv_cpu_ops = xen_cpu_ops;
1231 x86_platform.get_nmi_reason = xen_get_nmi_reason;
1233 x86_init.resources.memory_setup = xen_memory_setup;
1234 x86_init.oem.arch_setup = xen_arch_setup;
1235 x86_init.oem.banner = xen_banner;
1238 * Set up some pagetable state before starting to set any ptes.
1243 /* Prevent unwanted bits from being set in PTEs. */
1244 __supported_pte_mask &= ~_PAGE_GLOBAL;
1247 * Prevent page tables from being allocated in highmem, even
1248 * if CONFIG_HIGHPTE is enabled.
1250 __userpte_alloc_gfp &= ~__GFP_HIGHMEM;
1252 /* Work out if we support NX */
1256 xen_build_dynamic_phys_to_machine();
1259 * Set up kernel GDT and segment registers, mainly so that
1260 * -fstack-protector code can be executed.
1265 xen_init_capabilities();
1267 #ifdef CONFIG_X86_LOCAL_APIC
1269 * set up the basic apic ops.
1274 if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) {
1275 pv_mmu_ops.ptep_modify_prot_start = xen_ptep_modify_prot_start;
1276 pv_mmu_ops.ptep_modify_prot_commit = xen_ptep_modify_prot_commit;
1279 machine_ops = xen_machine_ops;
1282 * The only reliable way to retain the initial address of the
1283 * percpu gdt_page is to remember it here, so we can go and
1284 * mark it RW later, when the initial percpu area is freed.
1286 xen_initial_gdt = &per_cpu(gdt_page, 0);
1290 #ifdef CONFIG_ACPI_NUMA
1292 * The pages we from Xen are not related to machine pages, so
1293 * any NUMA information the kernel tries to get from ACPI will
1294 * be meaningless. Prevent it from trying.
1298 /* Let's presume PV guests always boot on vCPU with id 0. */
1299 per_cpu(xen_vcpu_id, 0) = 0;
1302 * Setup xen_vcpu early because start_kernel needs it for
1303 * local_irq_disable(), irqs_disabled().
1305 * Don't do the full vcpu_info placement stuff until we have
1306 * the cpu_possible_mask and a non-dummy shared_info.
1308 xen_vcpu_info_reset(0);
1310 WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_pv, xen_cpu_dead_pv));
1312 local_irq_disable();
1313 early_boot_irqs_disabled = true;
1315 xen_raw_console_write("mapping kernel into physical memory\n");
1316 xen_setup_kernel_pagetable((pgd_t *)xen_start_info->pt_base,
1317 xen_start_info->nr_pages);
1318 xen_reserve_special_pages();
1320 /* keep using Xen gdt for now; no urgent need to change it */
1322 #ifdef CONFIG_X86_32
1323 pv_info.kernel_rpl = 1;
1324 if (xen_feature(XENFEAT_supervisor_mode_kernel))
1325 pv_info.kernel_rpl = 0;
1327 pv_info.kernel_rpl = 0;
1329 /* set the limit of our address space */
1333 * We used to do this in xen_arch_setup, but that is too late
1334 * on AMD were early_cpu_init (run before ->arch_setup()) calls
1335 * early_amd_init which pokes 0xcf8 port.
1338 rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
1340 xen_raw_printk("physdev_op failed %d\n", rc);
1342 #ifdef CONFIG_X86_32
1343 /* set up basic CPUID stuff */
1344 cpu_detect(&new_cpu_data);
1345 set_cpu_cap(&new_cpu_data, X86_FEATURE_FPU);
1346 new_cpu_data.x86_capability[CPUID_1_EDX] = cpuid_edx(1);
1349 if (xen_start_info->mod_start) {
1350 if (xen_start_info->flags & SIF_MOD_START_PFN)
1351 initrd_start = PFN_PHYS(xen_start_info->mod_start);
1353 initrd_start = __pa(xen_start_info->mod_start);
1356 /* Poke various useful things into boot_params */
1357 boot_params.hdr.type_of_loader = (9 << 4) | 0;
1358 boot_params.hdr.ramdisk_image = initrd_start;
1359 boot_params.hdr.ramdisk_size = xen_start_info->mod_len;
1360 boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line);
1361 boot_params.hdr.hardware_subarch = X86_SUBARCH_XEN;
1363 if (!xen_initial_domain()) {
1364 add_preferred_console("xenboot", 0, NULL);
1365 add_preferred_console("tty", 0, NULL);
1366 add_preferred_console("hvc", 0, NULL);
1368 x86_init.pci.arch_init = pci_xen_init;
1370 const struct dom0_vga_console_info *info =
1371 (void *)((char *)xen_start_info +
1372 xen_start_info->console.dom0.info_off);
1373 struct xen_platform_op op = {
1374 .cmd = XENPF_firmware_info,
1375 .interface_version = XENPF_INTERFACE_VERSION,
1376 .u.firmware_info.type = XEN_FW_KBD_SHIFT_FLAGS,
1379 x86_platform.set_legacy_features =
1380 xen_dom0_set_legacy_features;
1381 xen_init_vga(info, xen_start_info->console.dom0.info_size);
1382 xen_start_info->console.domU.mfn = 0;
1383 xen_start_info->console.domU.evtchn = 0;
1385 if (HYPERVISOR_platform_op(&op) == 0)
1386 boot_params.kbd_status = op.u.firmware_info.u.kbd_shift_flags;
1388 /* Make sure ACS will be enabled */
1391 xen_acpi_sleep_register();
1393 /* Avoid searching for BIOS MP tables */
1394 x86_init.mpparse.find_smp_config = x86_init_noop;
1395 x86_init.mpparse.get_smp_config = x86_init_uint_noop;
1397 xen_boot_params_init_edd();
1400 /* PCI BIOS service won't work from a PV guest. */
1401 pci_probe &= ~PCI_PROBE_BIOS;
1403 xen_raw_console_write("about to get started...\n");
1405 /* We need this for printk timestamps */
1406 xen_setup_runstate_info(0);
1410 /* Start the world */
1411 #ifdef CONFIG_X86_32
1412 i386_start_kernel();
1414 cr4_init_shadow(); /* 32b kernel does this in i386_start_kernel() */
1415 x86_64_start_reservations((char *)__pa_symbol(&boot_params));
1419 static int xen_cpu_up_prepare_pv(unsigned int cpu)
1423 if (per_cpu(xen_vcpu, cpu) == NULL)
1426 xen_setup_timer(cpu);
1428 rc = xen_smp_intr_init(cpu);
1430 WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
1435 rc = xen_smp_intr_init_pv(cpu);
1437 WARN(1, "xen_smp_intr_init_pv() for CPU %d failed: %d\n",
1445 static int xen_cpu_dead_pv(unsigned int cpu)
1447 xen_smp_intr_free(cpu);
1448 xen_smp_intr_free_pv(cpu);
1450 xen_teardown_timer(cpu);
1455 static uint32_t __init xen_platform_pv(void)
1457 if (xen_pv_domain())
1458 return xen_cpuid_base();
1463 const struct hypervisor_x86 x86_hyper_xen_pv = {
1465 .detect = xen_platform_pv,
1466 .pin_vcpu = xen_pin_vcpu,
1468 EXPORT_SYMBOL(x86_hyper_xen_pv);