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/memblock.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/edd.h>
35 #include <linux/objtool.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>
48 #include <xen/hvc-console.h>
51 #include <asm/paravirt.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>
65 #include <asm/pgalloc.h>
66 #include <asm/tlbflush.h>
67 #include <asm/reboot.h>
68 #include <asm/stackprotector.h>
69 #include <asm/hypervisor.h>
70 #include <asm/mach_traps.h>
71 #include <asm/mwait.h>
72 #include <asm/pci_x86.h>
74 #ifdef CONFIG_X86_IOPL_IOPERM
75 #include <asm/io_bitmap.h>
79 #include <linux/acpi.h>
81 #include <acpi/pdc_intel.h>
82 #include <acpi/processor.h>
83 #include <xen/interface/platform.h>
89 #include "multicalls.h"
92 #include "../kernel/cpu/cpu.h" /* get_cpu_cap() */
94 void *xen_initial_gdt;
96 static int xen_cpu_up_prepare_pv(unsigned int cpu);
97 static int xen_cpu_dead_pv(unsigned int cpu);
100 struct desc_struct desc[3];
104 * Updating the 3 TLS descriptors in the GDT on every task switch is
105 * surprisingly expensive so we avoid updating them if they haven't
106 * changed. Since Xen writes different descriptors than the one
107 * passed in the update_descriptor hypercall we keep shadow copies to
110 static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc);
112 static void __init xen_banner(void)
114 unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL);
115 struct xen_extraversion extra;
116 HYPERVISOR_xen_version(XENVER_extraversion, &extra);
118 pr_info("Booting paravirtualized kernel on %s\n", pv_info.name);
119 pr_info("Xen version: %d.%d%s (preserve-AD)\n",
120 version >> 16, version & 0xffff, extra.extraversion);
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 pte = pfn_pte(pfn, prot);
357 * Careful: update_va_mapping() will fail if the virtual address
358 * we're poking isn't populated in the page tables. We don't
359 * need to worry about the direct map (that's always in the page
360 * tables), but we need to be careful about vmap space. In
361 * particular, the top level page table can lazily propagate
362 * entries between processes, so if we've switched mms since we
363 * vmapped the target in the first place, we might not have the
364 * top-level page table entry populated.
366 * We disable preemption because we want the same mm active when
367 * we probe the target and when we issue the hypercall. We'll
368 * have the same nominal mm, but if we're a kernel thread, lazy
369 * mm dropping could change our pgd.
371 * Out of an abundance of caution, this uses __get_user() to fault
372 * in the target address just in case there's some obscure case
373 * in which the target address isn't readable.
378 copy_from_kernel_nofault(&dummy, v, 1);
380 if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0))
383 va = __va(PFN_PHYS(pfn));
385 if (va != v && HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0))
391 static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries)
393 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
397 * We need to mark the all aliases of the LDT pages RO. We
398 * don't need to call vm_flush_aliases(), though, since that's
399 * only responsible for flushing aliases out the TLBs, not the
400 * page tables, and Xen will flush the TLB for us if needed.
402 * To avoid confusing future readers: none of this is necessary
403 * to load the LDT. The hypervisor only checks this when the
404 * LDT is faulted in due to subsequent descriptor access.
407 for (i = 0; i < entries; i += entries_per_page)
408 set_aliased_prot(ldt + i, PAGE_KERNEL_RO);
411 static void xen_free_ldt(struct desc_struct *ldt, unsigned entries)
413 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
416 for (i = 0; i < entries; i += entries_per_page)
417 set_aliased_prot(ldt + i, PAGE_KERNEL);
420 static void xen_set_ldt(const void *addr, unsigned entries)
422 struct mmuext_op *op;
423 struct multicall_space mcs = xen_mc_entry(sizeof(*op));
425 trace_xen_cpu_set_ldt(addr, entries);
428 op->cmd = MMUEXT_SET_LDT;
429 op->arg1.linear_addr = (unsigned long)addr;
430 op->arg2.nr_ents = entries;
432 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
434 xen_mc_issue(PARAVIRT_LAZY_CPU);
437 static void xen_load_gdt(const struct desc_ptr *dtr)
439 unsigned long va = dtr->address;
440 unsigned int size = dtr->size + 1;
441 unsigned long pfn, mfn;
446 /* @size should be at most GDT_SIZE which is smaller than PAGE_SIZE. */
447 BUG_ON(size > PAGE_SIZE);
448 BUG_ON(va & ~PAGE_MASK);
451 * The GDT is per-cpu and is in the percpu data area.
452 * That can be virtually mapped, so we need to do a
453 * page-walk to get the underlying MFN for the
454 * hypercall. The page can also be in the kernel's
455 * linear range, so we need to RO that mapping too.
457 ptep = lookup_address(va, &level);
458 BUG_ON(ptep == NULL);
460 pfn = pte_pfn(*ptep);
461 mfn = pfn_to_mfn(pfn);
462 virt = __va(PFN_PHYS(pfn));
464 make_lowmem_page_readonly((void *)va);
465 make_lowmem_page_readonly(virt);
467 if (HYPERVISOR_set_gdt(&mfn, size / sizeof(struct desc_struct)))
472 * load_gdt for early boot, when the gdt is only mapped once
474 static void __init xen_load_gdt_boot(const struct desc_ptr *dtr)
476 unsigned long va = dtr->address;
477 unsigned int size = dtr->size + 1;
478 unsigned long pfn, mfn;
481 /* @size should be at most GDT_SIZE which is smaller than PAGE_SIZE. */
482 BUG_ON(size > PAGE_SIZE);
483 BUG_ON(va & ~PAGE_MASK);
485 pfn = virt_to_pfn(va);
486 mfn = pfn_to_mfn(pfn);
488 pte = pfn_pte(pfn, PAGE_KERNEL_RO);
490 if (HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0))
493 if (HYPERVISOR_set_gdt(&mfn, size / sizeof(struct desc_struct)))
497 static inline bool desc_equal(const struct desc_struct *d1,
498 const struct desc_struct *d2)
500 return !memcmp(d1, d2, sizeof(*d1));
503 static void load_TLS_descriptor(struct thread_struct *t,
504 unsigned int cpu, unsigned int i)
506 struct desc_struct *shadow = &per_cpu(shadow_tls_desc, cpu).desc[i];
507 struct desc_struct *gdt;
509 struct multicall_space mc;
511 if (desc_equal(shadow, &t->tls_array[i]))
514 *shadow = t->tls_array[i];
516 gdt = get_cpu_gdt_rw(cpu);
517 maddr = arbitrary_virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]);
518 mc = __xen_mc_entry(0);
520 MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]);
523 static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
526 * In lazy mode we need to zero %fs, otherwise we may get an
527 * exception between the new %fs descriptor being loaded and
528 * %fs being effectively cleared at __switch_to().
530 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU)
535 load_TLS_descriptor(t, cpu, 0);
536 load_TLS_descriptor(t, cpu, 1);
537 load_TLS_descriptor(t, cpu, 2);
539 xen_mc_issue(PARAVIRT_LAZY_CPU);
542 static void xen_load_gs_index(unsigned int idx)
544 if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx))
548 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
551 xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]);
552 u64 entry = *(u64 *)ptr;
554 trace_xen_cpu_write_ldt_entry(dt, entrynum, entry);
559 if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry))
565 void noist_exc_debug(struct pt_regs *regs);
567 DEFINE_IDTENTRY_RAW(xenpv_exc_nmi)
569 /* On Xen PV, NMI doesn't use IST. The C part is the same as native. */
573 DEFINE_IDTENTRY_RAW_ERRORCODE(xenpv_exc_double_fault)
575 /* On Xen PV, DF doesn't use IST. The C part is the same as native. */
576 exc_double_fault(regs, error_code);
579 DEFINE_IDTENTRY_RAW(xenpv_exc_debug)
582 * There's no IST on Xen PV, but we still need to dispatch
583 * to the correct handler.
586 noist_exc_debug(regs);
591 DEFINE_IDTENTRY_RAW(exc_xen_unknown_trap)
593 /* This should never happen and there is no way to handle it. */
594 instrumentation_begin();
595 pr_err("Unknown trap in Xen PV mode.");
597 instrumentation_end();
600 #ifdef CONFIG_X86_MCE
601 DEFINE_IDTENTRY_RAW(xenpv_exc_machine_check)
604 * There's no IST on Xen PV, but we still need to dispatch
605 * to the correct handler.
608 noist_exc_machine_check(regs);
610 exc_machine_check(regs);
614 struct trap_array_entry {
620 #define TRAP_ENTRY(func, ist_ok) { \
621 .orig = asm_##func, \
622 .xen = xen_asm_##func, \
625 #define TRAP_ENTRY_REDIR(func, ist_ok) { \
626 .orig = asm_##func, \
627 .xen = xen_asm_xenpv_##func, \
630 static struct trap_array_entry trap_array[] = {
631 TRAP_ENTRY_REDIR(exc_debug, true ),
632 TRAP_ENTRY_REDIR(exc_double_fault, true ),
633 #ifdef CONFIG_X86_MCE
634 TRAP_ENTRY_REDIR(exc_machine_check, true ),
636 TRAP_ENTRY_REDIR(exc_nmi, true ),
637 TRAP_ENTRY(exc_int3, false ),
638 TRAP_ENTRY(exc_overflow, false ),
639 #ifdef CONFIG_IA32_EMULATION
640 { entry_INT80_compat, xen_entry_INT80_compat, false },
642 TRAP_ENTRY(exc_page_fault, false ),
643 TRAP_ENTRY(exc_divide_error, false ),
644 TRAP_ENTRY(exc_bounds, false ),
645 TRAP_ENTRY(exc_invalid_op, false ),
646 TRAP_ENTRY(exc_device_not_available, false ),
647 TRAP_ENTRY(exc_coproc_segment_overrun, false ),
648 TRAP_ENTRY(exc_invalid_tss, false ),
649 TRAP_ENTRY(exc_segment_not_present, false ),
650 TRAP_ENTRY(exc_stack_segment, false ),
651 TRAP_ENTRY(exc_general_protection, false ),
652 TRAP_ENTRY(exc_spurious_interrupt_bug, false ),
653 TRAP_ENTRY(exc_coprocessor_error, false ),
654 TRAP_ENTRY(exc_alignment_check, false ),
655 TRAP_ENTRY(exc_simd_coprocessor_error, false ),
658 static bool __ref get_trap_addr(void **addr, unsigned int ist)
661 bool ist_okay = false;
665 * Replace trap handler addresses by Xen specific ones.
666 * Check for known traps using IST and whitelist them.
667 * The debugger ones are the only ones we care about.
668 * Xen will handle faults like double_fault, so we should never see
669 * them. Warn if there's an unexpected IST-using fault handler.
671 for (nr = 0; nr < ARRAY_SIZE(trap_array); nr++) {
672 struct trap_array_entry *entry = trap_array + nr;
674 if (*addr == entry->orig) {
676 ist_okay = entry->ist_okay;
682 if (nr == ARRAY_SIZE(trap_array) &&
683 *addr >= (void *)early_idt_handler_array[0] &&
684 *addr < (void *)early_idt_handler_array[NUM_EXCEPTION_VECTORS]) {
685 nr = (*addr - (void *)early_idt_handler_array[0]) /
686 EARLY_IDT_HANDLER_SIZE;
687 *addr = (void *)xen_early_idt_handler_array[nr];
692 *addr = (void *)xen_asm_exc_xen_unknown_trap;
694 if (WARN_ON(found && ist != 0 && !ist_okay))
700 static int cvt_gate_to_trap(int vector, const gate_desc *val,
701 struct trap_info *info)
705 if (val->bits.type != GATE_TRAP && val->bits.type != GATE_INTERRUPT)
708 info->vector = vector;
710 addr = gate_offset(val);
711 if (!get_trap_addr((void **)&addr, val->bits.ist))
713 info->address = addr;
715 info->cs = gate_segment(val);
716 info->flags = val->bits.dpl;
717 /* interrupt gates clear IF */
718 if (val->bits.type == GATE_INTERRUPT)
719 info->flags |= 1 << 2;
724 /* Locations of each CPU's IDT */
725 static DEFINE_PER_CPU(struct desc_ptr, idt_desc);
727 /* Set an IDT entry. If the entry is part of the current IDT, then
729 static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g)
731 unsigned long p = (unsigned long)&dt[entrynum];
732 unsigned long start, end;
734 trace_xen_cpu_write_idt_entry(dt, entrynum, g);
738 start = __this_cpu_read(idt_desc.address);
739 end = start + __this_cpu_read(idt_desc.size) + 1;
743 native_write_idt_entry(dt, entrynum, g);
745 if (p >= start && (p + 8) <= end) {
746 struct trap_info info[2];
750 if (cvt_gate_to_trap(entrynum, g, &info[0]))
751 if (HYPERVISOR_set_trap_table(info))
758 static void xen_convert_trap_info(const struct desc_ptr *desc,
759 struct trap_info *traps)
761 unsigned in, out, count;
763 count = (desc->size+1) / sizeof(gate_desc);
766 for (in = out = 0; in < count; in++) {
767 gate_desc *entry = (gate_desc *)(desc->address) + in;
769 if (cvt_gate_to_trap(in, entry, &traps[out]))
772 traps[out].address = 0;
775 void xen_copy_trap_info(struct trap_info *traps)
777 const struct desc_ptr *desc = this_cpu_ptr(&idt_desc);
779 xen_convert_trap_info(desc, traps);
782 /* Load a new IDT into Xen. In principle this can be per-CPU, so we
783 hold a spinlock to protect the static traps[] array (static because
784 it avoids allocation, and saves stack space). */
785 static void xen_load_idt(const struct desc_ptr *desc)
787 static DEFINE_SPINLOCK(lock);
788 static struct trap_info traps[257];
790 trace_xen_cpu_load_idt(desc);
794 memcpy(this_cpu_ptr(&idt_desc), desc, sizeof(idt_desc));
796 xen_convert_trap_info(desc, traps);
799 if (HYPERVISOR_set_trap_table(traps))
805 /* Write a GDT descriptor entry. Ignore LDT descriptors, since
806 they're handled differently. */
807 static void xen_write_gdt_entry(struct desc_struct *dt, int entry,
808 const void *desc, int type)
810 trace_xen_cpu_write_gdt_entry(dt, entry, desc, type);
821 xmaddr_t maddr = arbitrary_virt_to_machine(&dt[entry]);
824 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
834 * Version of write_gdt_entry for use at early boot-time needed to
835 * update an entry as simply as possible.
837 static void __init xen_write_gdt_entry_boot(struct desc_struct *dt, int entry,
838 const void *desc, int type)
840 trace_xen_cpu_write_gdt_entry(dt, entry, desc, type);
849 xmaddr_t maddr = virt_to_machine(&dt[entry]);
851 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
852 dt[entry] = *(struct desc_struct *)desc;
858 static void xen_load_sp0(unsigned long sp0)
860 struct multicall_space mcs;
862 mcs = xen_mc_entry(0);
863 MULTI_stack_switch(mcs.mc, __KERNEL_DS, sp0);
864 xen_mc_issue(PARAVIRT_LAZY_CPU);
865 this_cpu_write(cpu_tss_rw.x86_tss.sp0, sp0);
868 #ifdef CONFIG_X86_IOPL_IOPERM
869 static void xen_invalidate_io_bitmap(void)
871 struct physdev_set_iobitmap iobitmap = {
876 native_tss_invalidate_io_bitmap();
877 HYPERVISOR_physdev_op(PHYSDEVOP_set_iobitmap, &iobitmap);
880 static void xen_update_io_bitmap(void)
882 struct physdev_set_iobitmap iobitmap;
883 struct tss_struct *tss = this_cpu_ptr(&cpu_tss_rw);
885 native_tss_update_io_bitmap();
887 iobitmap.bitmap = (uint8_t *)(&tss->x86_tss) +
888 tss->x86_tss.io_bitmap_base;
889 if (tss->x86_tss.io_bitmap_base == IO_BITMAP_OFFSET_INVALID)
890 iobitmap.nr_ports = 0;
892 iobitmap.nr_ports = IO_BITMAP_BITS;
894 HYPERVISOR_physdev_op(PHYSDEVOP_set_iobitmap, &iobitmap);
898 static void xen_io_delay(void)
902 static DEFINE_PER_CPU(unsigned long, xen_cr0_value);
904 static unsigned long xen_read_cr0(void)
906 unsigned long cr0 = this_cpu_read(xen_cr0_value);
908 if (unlikely(cr0 == 0)) {
909 cr0 = native_read_cr0();
910 this_cpu_write(xen_cr0_value, cr0);
916 static void xen_write_cr0(unsigned long cr0)
918 struct multicall_space mcs;
920 this_cpu_write(xen_cr0_value, cr0);
922 /* Only pay attention to cr0.TS; everything else is
924 mcs = xen_mc_entry(0);
926 MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0);
928 xen_mc_issue(PARAVIRT_LAZY_CPU);
931 static void xen_write_cr4(unsigned long cr4)
933 cr4 &= ~(X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PCE);
935 native_write_cr4(cr4);
938 static u64 xen_read_msr_safe(unsigned int msr, int *err)
942 if (pmu_msr_read(msr, &val, err))
945 val = native_read_msr_safe(msr, err);
947 case MSR_IA32_APICBASE:
948 val &= ~X2APIC_ENABLE;
954 static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
963 case MSR_FS_BASE: which = SEGBASE_FS; goto set;
964 case MSR_KERNEL_GS_BASE: which = SEGBASE_GS_USER; goto set;
965 case MSR_GS_BASE: which = SEGBASE_GS_KERNEL; goto set;
968 base = ((u64)high << 32) | low;
969 if (HYPERVISOR_set_segment_base(which, base) != 0)
976 case MSR_SYSCALL_MASK:
977 case MSR_IA32_SYSENTER_CS:
978 case MSR_IA32_SYSENTER_ESP:
979 case MSR_IA32_SYSENTER_EIP:
980 /* Fast syscall setup is all done in hypercalls, so
981 these are all ignored. Stub them out here to stop
982 Xen console noise. */
986 if (!pmu_msr_write(msr, low, high, &ret))
987 ret = native_write_msr_safe(msr, low, high);
993 static u64 xen_read_msr(unsigned int msr)
996 * This will silently swallow a #GP from RDMSR. It may be worth
1001 return xen_read_msr_safe(msr, &err);
1004 static void xen_write_msr(unsigned int msr, unsigned low, unsigned high)
1007 * This will silently swallow a #GP from WRMSR. It may be worth
1010 xen_write_msr_safe(msr, low, high);
1013 /* This is called once we have the cpu_possible_mask */
1014 void __init xen_setup_vcpu_info_placement(void)
1018 for_each_possible_cpu(cpu) {
1019 /* Set up direct vCPU id mapping for PV guests. */
1020 per_cpu(xen_vcpu_id, cpu) = cpu;
1023 * xen_vcpu_setup(cpu) can fail -- in which case it
1024 * falls back to the shared_info version for cpus
1025 * where xen_vcpu_nr(cpu) < MAX_VIRT_CPUS.
1027 * xen_cpu_up_prepare_pv() handles the rest by failing
1030 (void) xen_vcpu_setup(cpu);
1034 * xen_vcpu_setup managed to place the vcpu_info within the
1035 * percpu area for all cpus, so make use of it.
1037 if (xen_have_vcpu_info_placement) {
1038 pv_ops.irq.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct);
1039 pv_ops.irq.irq_disable =
1040 __PV_IS_CALLEE_SAVE(xen_irq_disable_direct);
1041 pv_ops.irq.irq_enable =
1042 __PV_IS_CALLEE_SAVE(xen_irq_enable_direct);
1043 pv_ops.mmu.read_cr2 =
1044 __PV_IS_CALLEE_SAVE(xen_read_cr2_direct);
1048 static const struct pv_info xen_info __initconst = {
1049 .extra_user_64bit_cs = FLAT_USER_CS64,
1053 static const struct pv_cpu_ops xen_cpu_ops __initconst = {
1056 .set_debugreg = xen_set_debugreg,
1057 .get_debugreg = xen_get_debugreg,
1059 .read_cr0 = xen_read_cr0,
1060 .write_cr0 = xen_write_cr0,
1062 .write_cr4 = xen_write_cr4,
1064 .wbinvd = native_wbinvd,
1066 .read_msr = xen_read_msr,
1067 .write_msr = xen_write_msr,
1069 .read_msr_safe = xen_read_msr_safe,
1070 .write_msr_safe = xen_write_msr_safe,
1072 .read_pmc = xen_read_pmc,
1074 .load_tr_desc = paravirt_nop,
1075 .set_ldt = xen_set_ldt,
1076 .load_gdt = xen_load_gdt,
1077 .load_idt = xen_load_idt,
1078 .load_tls = xen_load_tls,
1079 .load_gs_index = xen_load_gs_index,
1081 .alloc_ldt = xen_alloc_ldt,
1082 .free_ldt = xen_free_ldt,
1084 .store_tr = xen_store_tr,
1086 .write_ldt_entry = xen_write_ldt_entry,
1087 .write_gdt_entry = xen_write_gdt_entry,
1088 .write_idt_entry = xen_write_idt_entry,
1089 .load_sp0 = xen_load_sp0,
1091 #ifdef CONFIG_X86_IOPL_IOPERM
1092 .invalidate_io_bitmap = xen_invalidate_io_bitmap,
1093 .update_io_bitmap = xen_update_io_bitmap,
1095 .io_delay = xen_io_delay,
1097 .start_context_switch = paravirt_start_context_switch,
1098 .end_context_switch = xen_end_context_switch,
1101 static void xen_restart(char *msg)
1103 xen_reboot(SHUTDOWN_reboot);
1106 static void xen_machine_halt(void)
1108 xen_reboot(SHUTDOWN_poweroff);
1111 static void xen_machine_power_off(void)
1115 xen_reboot(SHUTDOWN_poweroff);
1118 static void xen_crash_shutdown(struct pt_regs *regs)
1120 xen_reboot(SHUTDOWN_crash);
1123 static const struct machine_ops xen_machine_ops __initconst = {
1124 .restart = xen_restart,
1125 .halt = xen_machine_halt,
1126 .power_off = xen_machine_power_off,
1127 .shutdown = xen_machine_halt,
1128 .crash_shutdown = xen_crash_shutdown,
1129 .emergency_restart = xen_emergency_restart,
1132 static unsigned char xen_get_nmi_reason(void)
1134 unsigned char reason = 0;
1136 /* Construct a value which looks like it came from port 0x61. */
1137 if (test_bit(_XEN_NMIREASON_io_error,
1138 &HYPERVISOR_shared_info->arch.nmi_reason))
1139 reason |= NMI_REASON_IOCHK;
1140 if (test_bit(_XEN_NMIREASON_pci_serr,
1141 &HYPERVISOR_shared_info->arch.nmi_reason))
1142 reason |= NMI_REASON_SERR;
1147 static void __init xen_boot_params_init_edd(void)
1149 #if IS_ENABLED(CONFIG_EDD)
1150 struct xen_platform_op op;
1151 struct edd_info *edd_info;
1156 edd_info = boot_params.eddbuf;
1157 mbr_signature = boot_params.edd_mbr_sig_buffer;
1159 op.cmd = XENPF_firmware_info;
1161 op.u.firmware_info.type = XEN_FW_DISK_INFO;
1162 for (nr = 0; nr < EDDMAXNR; nr++) {
1163 struct edd_info *info = edd_info + nr;
1165 op.u.firmware_info.index = nr;
1166 info->params.length = sizeof(info->params);
1167 set_xen_guest_handle(op.u.firmware_info.u.disk_info.edd_params,
1169 ret = HYPERVISOR_platform_op(&op);
1173 #define C(x) info->x = op.u.firmware_info.u.disk_info.x
1176 C(interface_support);
1177 C(legacy_max_cylinder);
1179 C(legacy_sectors_per_track);
1182 boot_params.eddbuf_entries = nr;
1184 op.u.firmware_info.type = XEN_FW_DISK_MBR_SIGNATURE;
1185 for (nr = 0; nr < EDD_MBR_SIG_MAX; nr++) {
1186 op.u.firmware_info.index = nr;
1187 ret = HYPERVISOR_platform_op(&op);
1190 mbr_signature[nr] = op.u.firmware_info.u.disk_mbr_signature.mbr_signature;
1192 boot_params.edd_mbr_sig_buf_entries = nr;
1197 * Set up the GDT and segment registers for -fstack-protector. Until
1198 * we do this, we have to be careful not to call any stack-protected
1199 * function, which is most of the kernel.
1201 static void __init xen_setup_gdt(int cpu)
1203 pv_ops.cpu.write_gdt_entry = xen_write_gdt_entry_boot;
1204 pv_ops.cpu.load_gdt = xen_load_gdt_boot;
1206 switch_to_new_gdt(cpu);
1208 pv_ops.cpu.write_gdt_entry = xen_write_gdt_entry;
1209 pv_ops.cpu.load_gdt = xen_load_gdt;
1212 static void __init xen_dom0_set_legacy_features(void)
1214 x86_platform.legacy.rtc = 1;
1217 /* First C function to be called on Xen boot */
1218 asmlinkage __visible void __init xen_start_kernel(void)
1220 struct physdev_set_iopl set_iopl;
1221 unsigned long initrd_start = 0;
1224 if (!xen_start_info)
1227 xen_domain_type = XEN_PV_DOMAIN;
1228 xen_start_flags = xen_start_info->flags;
1230 xen_setup_features();
1232 /* Install Xen paravirt ops */
1234 pv_ops.cpu = xen_cpu_ops;
1235 paravirt_iret = xen_iret;
1239 * Setup xen_vcpu early because it is needed for
1240 * local_irq_disable(), irqs_disabled(), e.g. in printk().
1242 * Don't do the full vcpu_info placement stuff until we have
1243 * the cpu_possible_mask and a non-dummy shared_info.
1245 xen_vcpu_info_reset(0);
1247 x86_platform.get_nmi_reason = xen_get_nmi_reason;
1249 x86_init.resources.memory_setup = xen_memory_setup;
1250 x86_init.irqs.intr_mode_select = x86_init_noop;
1251 x86_init.irqs.intr_mode_init = x86_init_noop;
1252 x86_init.oem.arch_setup = xen_arch_setup;
1253 x86_init.oem.banner = xen_banner;
1254 x86_init.hyper.init_platform = xen_pv_init_platform;
1255 x86_init.hyper.guest_late_init = xen_pv_guest_late_init;
1258 * Set up some pagetable state before starting to set any ptes.
1261 xen_setup_machphys_mapping();
1264 /* Prevent unwanted bits from being set in PTEs. */
1265 __supported_pte_mask &= ~_PAGE_GLOBAL;
1266 __default_kernel_pte_mask &= ~_PAGE_GLOBAL;
1269 * Prevent page tables from being allocated in highmem, even
1270 * if CONFIG_HIGHPTE is enabled.
1272 __userpte_alloc_gfp &= ~__GFP_HIGHMEM;
1275 xen_build_dynamic_phys_to_machine();
1277 /* Work out if we support NX */
1278 get_cpu_cap(&boot_cpu_data);
1282 * Set up kernel GDT and segment registers, mainly so that
1283 * -fstack-protector code can be executed.
1287 /* Determine virtual and physical address sizes */
1288 get_cpu_address_sizes(&boot_cpu_data);
1290 /* Let's presume PV guests always boot on vCPU with id 0. */
1291 per_cpu(xen_vcpu_id, 0) = 0;
1293 idt_setup_early_handler();
1295 xen_init_capabilities();
1297 #ifdef CONFIG_X86_LOCAL_APIC
1299 * set up the basic apic ops.
1304 machine_ops = xen_machine_ops;
1307 * The only reliable way to retain the initial address of the
1308 * percpu gdt_page is to remember it here, so we can go and
1309 * mark it RW later, when the initial percpu area is freed.
1311 xen_initial_gdt = &per_cpu(gdt_page, 0);
1315 #ifdef CONFIG_ACPI_NUMA
1317 * The pages we from Xen are not related to machine pages, so
1318 * any NUMA information the kernel tries to get from ACPI will
1319 * be meaningless. Prevent it from trying.
1323 WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_pv, xen_cpu_dead_pv));
1325 local_irq_disable();
1326 early_boot_irqs_disabled = true;
1328 xen_raw_console_write("mapping kernel into physical memory\n");
1329 xen_setup_kernel_pagetable((pgd_t *)xen_start_info->pt_base,
1330 xen_start_info->nr_pages);
1331 xen_reserve_special_pages();
1334 * We used to do this in xen_arch_setup, but that is too late
1335 * on AMD were early_cpu_init (run before ->arch_setup()) calls
1336 * early_amd_init which pokes 0xcf8 port.
1339 rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
1341 xen_raw_printk("physdev_op failed %d\n", rc);
1344 if (xen_start_info->mod_start) {
1345 if (xen_start_info->flags & SIF_MOD_START_PFN)
1346 initrd_start = PFN_PHYS(xen_start_info->mod_start);
1348 initrd_start = __pa(xen_start_info->mod_start);
1351 /* Poke various useful things into boot_params */
1352 boot_params.hdr.type_of_loader = (9 << 4) | 0;
1353 boot_params.hdr.ramdisk_image = initrd_start;
1354 boot_params.hdr.ramdisk_size = xen_start_info->mod_len;
1355 boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line);
1356 boot_params.hdr.hardware_subarch = X86_SUBARCH_XEN;
1358 if (!xen_initial_domain()) {
1359 add_preferred_console("xenboot", 0, NULL);
1361 x86_init.pci.arch_init = pci_xen_init;
1363 const struct dom0_vga_console_info *info =
1364 (void *)((char *)xen_start_info +
1365 xen_start_info->console.dom0.info_off);
1366 struct xen_platform_op op = {
1367 .cmd = XENPF_firmware_info,
1368 .interface_version = XENPF_INTERFACE_VERSION,
1369 .u.firmware_info.type = XEN_FW_KBD_SHIFT_FLAGS,
1372 x86_platform.set_legacy_features =
1373 xen_dom0_set_legacy_features;
1374 xen_init_vga(info, xen_start_info->console.dom0.info_size);
1375 xen_start_info->console.domU.mfn = 0;
1376 xen_start_info->console.domU.evtchn = 0;
1378 if (HYPERVISOR_platform_op(&op) == 0)
1379 boot_params.kbd_status = op.u.firmware_info.u.kbd_shift_flags;
1381 /* Make sure ACS will be enabled */
1384 xen_acpi_sleep_register();
1386 /* Avoid searching for BIOS MP tables */
1387 x86_init.mpparse.find_smp_config = x86_init_noop;
1388 x86_init.mpparse.get_smp_config = x86_init_uint_noop;
1390 xen_boot_params_init_edd();
1394 * Disable selecting "Firmware First mode" for correctable
1395 * memory errors, as this is the duty of the hypervisor to
1398 acpi_disable_cmcff = 1;
1402 if (!boot_params.screen_info.orig_video_isVGA)
1403 add_preferred_console("tty", 0, NULL);
1404 add_preferred_console("hvc", 0, NULL);
1405 if (boot_params.screen_info.orig_video_isVGA)
1406 add_preferred_console("tty", 0, NULL);
1409 /* PCI BIOS service won't work from a PV guest. */
1410 pci_probe &= ~PCI_PROBE_BIOS;
1412 xen_raw_console_write("about to get started...\n");
1414 /* We need this for printk timestamps */
1415 xen_setup_runstate_info(0);
1417 xen_efi_init(&boot_params);
1419 /* Start the world */
1420 cr4_init_shadow(); /* 32b kernel does this in i386_start_kernel() */
1421 x86_64_start_reservations((char *)__pa_symbol(&boot_params));
1424 static int xen_cpu_up_prepare_pv(unsigned int cpu)
1428 if (per_cpu(xen_vcpu, cpu) == NULL)
1431 xen_setup_timer(cpu);
1433 rc = xen_smp_intr_init(cpu);
1435 WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
1440 rc = xen_smp_intr_init_pv(cpu);
1442 WARN(1, "xen_smp_intr_init_pv() for CPU %d failed: %d\n",
1450 static int xen_cpu_dead_pv(unsigned int cpu)
1452 xen_smp_intr_free(cpu);
1453 xen_smp_intr_free_pv(cpu);
1455 xen_teardown_timer(cpu);
1460 static uint32_t __init xen_platform_pv(void)
1462 if (xen_pv_domain())
1463 return xen_cpuid_base();
1468 const __initconst struct hypervisor_x86 x86_hyper_xen_pv = {
1470 .detect = xen_platform_pv,
1471 .type = X86_HYPER_XEN_PV,
1472 .runtime.pin_vcpu = xen_pin_vcpu,
1473 .ignore_nopv = true,