arch/x86/kernel/paravirt.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*  Paravirtualization interfaces
   3     Copyright (C) 2006 Rusty Russell IBM Corporation
   4
   5
   6     2007 - x86_64 support added by Glauber de Oliveira Costa, Red Hat Inc
   7 */
   8
   9 #include <linux/errno.h>
  10 #include <linux/init.h>
  11 #include <linux/export.h>
  12 #include <linux/efi.h>
  13 #include <linux/bcd.h>
  14 #include <linux/highmem.h>
  15 #include <linux/kprobes.h>
  16 #include <linux/pgtable.h>
  17 #include <linux/static_call.h>
  18
  19 #include <asm/bug.h>
  20 #include <asm/paravirt.h>
  21 #include <asm/debugreg.h>
  22 #include <asm/desc.h>
  23 #include <asm/setup.h>
  24 #include <asm/time.h>
  25 #include <asm/pgalloc.h>
  26 #include <asm/irq.h>
  27 #include <asm/delay.h>
  28 #include <asm/fixmap.h>
  29 #include <asm/apic.h>
  30 #include <asm/tlbflush.h>
  31 #include <asm/timer.h>
  32 #include <asm/special_insns.h>
  33 #include <asm/tlb.h>
  34 #include <asm/io_bitmap.h>
  35 #include <asm/gsseg.h>
  36
  37 /* stub always returning 0. */
  38 DEFINE_ASM_FUNC(paravirt_ret0, "xor %eax,%eax", .entry.text);
  39
  40 void __init default_banner(void)
  41 {
  42         printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
  43                pv_info.name);
  44 }
  45
  46 #ifdef CONFIG_PARAVIRT_XXL
  47 DEFINE_ASM_FUNC(_paravirt_ident_64, "mov %rdi, %rax", .text);
  48 DEFINE_ASM_FUNC(pv_native_save_fl, "pushf; pop %rax", .noinstr.text);
  49 DEFINE_ASM_FUNC(pv_native_irq_disable, "cli", .noinstr.text);
  50 DEFINE_ASM_FUNC(pv_native_irq_enable, "sti", .noinstr.text);
  51 DEFINE_ASM_FUNC(pv_native_read_cr2, "mov %cr2, %rax", .noinstr.text);
  52 #endif
  53
  54 DEFINE_STATIC_KEY_FALSE(virt_spin_lock_key);
  55
  56 void __init native_pv_lock_init(void)
  57 {
  58         if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
  59                 static_branch_enable(&virt_spin_lock_key);
  60 }
  61
  62 static void native_tlb_remove_table(struct mmu_gather *tlb, void *table)
  63 {
  64         tlb_remove_page(tlb, table);
  65 }
  66
  67 struct static_key paravirt_steal_enabled;
  68 struct static_key paravirt_steal_rq_enabled;
  69
  70 static u64 native_steal_clock(int cpu)
  71 {
  72         return 0;
  73 }
  74
  75 DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock);
  76 DEFINE_STATIC_CALL(pv_sched_clock, native_sched_clock);
  77
  78 void paravirt_set_sched_clock(u64 (*func)(void))
  79 {
  80         static_call_update(pv_sched_clock, func);
  81 }
  82
  83 /* These are in entry.S */
  84 static struct resource reserve_ioports = {
  85         .start = 0,
  86         .end = IO_SPACE_LIMIT,
  87         .name = "paravirt-ioport",
  88         .flags = IORESOURCE_IO | IORESOURCE_BUSY,
  89 };
  90
  91 /*
  92  * Reserve the whole legacy IO space to prevent any legacy drivers
  93  * from wasting time probing for their hardware.  This is a fairly
  94  * brute-force approach to disabling all non-virtual drivers.
  95  *
  96  * Note that this must be called very early to have any effect.
  97  */
  98 int paravirt_disable_iospace(void)
  99 {
 100         return request_resource(&ioport_resource, &reserve_ioports);
 101 }
 102
 103 #ifdef CONFIG_PARAVIRT_XXL
 104 static noinstr void pv_native_write_cr2(unsigned long val)
 105 {
 106         native_write_cr2(val);
 107 }
 108
 109 static noinstr unsigned long pv_native_get_debugreg(int regno)
 110 {
 111         return native_get_debugreg(regno);
 112 }
 113
 114 static noinstr void pv_native_set_debugreg(int regno, unsigned long val)
 115 {
 116         native_set_debugreg(regno, val);
 117 }
 118
 119 noinstr void pv_native_wbinvd(void)
 120 {
 121         native_wbinvd();
 122 }
 123
 124 static noinstr void pv_native_safe_halt(void)
 125 {
 126         native_safe_halt();
 127 }
 128 #endif
 129
 130 struct pv_info pv_info = {
 131         .name = "bare hardware",
 132 #ifdef CONFIG_PARAVIRT_XXL
 133         .extra_user_64bit_cs = __USER_CS,
 134 #endif
 135 };
 136
 137 /* 64-bit pagetable entries */
 138 #define PTE_IDENT       __PV_IS_CALLEE_SAVE(_paravirt_ident_64)
 139
 140 struct paravirt_patch_template pv_ops = {
 141         /* Cpu ops. */
 142         .cpu.io_delay           = native_io_delay,
 143
 144 #ifdef CONFIG_PARAVIRT_XXL
 145         .cpu.cpuid              = native_cpuid,
 146         .cpu.get_debugreg       = pv_native_get_debugreg,
 147         .cpu.set_debugreg       = pv_native_set_debugreg,
 148         .cpu.read_cr0           = native_read_cr0,
 149         .cpu.write_cr0          = native_write_cr0,
 150         .cpu.write_cr4          = native_write_cr4,
 151         .cpu.wbinvd             = pv_native_wbinvd,
 152         .cpu.read_msr           = native_read_msr,
 153         .cpu.write_msr          = native_write_msr,
 154         .cpu.read_msr_safe      = native_read_msr_safe,
 155         .cpu.write_msr_safe     = native_write_msr_safe,
 156         .cpu.read_pmc           = native_read_pmc,
 157         .cpu.load_tr_desc       = native_load_tr_desc,
 158         .cpu.set_ldt            = native_set_ldt,
 159         .cpu.load_gdt           = native_load_gdt,
 160         .cpu.load_idt           = native_load_idt,
 161         .cpu.store_tr           = native_store_tr,
 162         .cpu.load_tls           = native_load_tls,
 163         .cpu.load_gs_index      = native_load_gs_index,
 164         .cpu.write_ldt_entry    = native_write_ldt_entry,
 165         .cpu.write_gdt_entry    = native_write_gdt_entry,
 166         .cpu.write_idt_entry    = native_write_idt_entry,
 167
 168         .cpu.alloc_ldt          = paravirt_nop,
 169         .cpu.free_ldt           = paravirt_nop,
 170
 171         .cpu.load_sp0           = native_load_sp0,
 172
 173 #ifdef CONFIG_X86_IOPL_IOPERM
 174         .cpu.invalidate_io_bitmap       = native_tss_invalidate_io_bitmap,
 175         .cpu.update_io_bitmap           = native_tss_update_io_bitmap,
 176 #endif
 177
 178         .cpu.start_context_switch       = paravirt_nop,
 179         .cpu.end_context_switch         = paravirt_nop,
 180
 181         /* Irq ops. */
 182         .irq.save_fl            = __PV_IS_CALLEE_SAVE(pv_native_save_fl),
 183         .irq.irq_disable        = __PV_IS_CALLEE_SAVE(pv_native_irq_disable),
 184         .irq.irq_enable         = __PV_IS_CALLEE_SAVE(pv_native_irq_enable),
 185         .irq.safe_halt          = pv_native_safe_halt,
 186         .irq.halt               = native_halt,
 187 #endif /* CONFIG_PARAVIRT_XXL */
 188
 189         /* Mmu ops. */
 190         .mmu.flush_tlb_user     = native_flush_tlb_local,
 191         .mmu.flush_tlb_kernel   = native_flush_tlb_global,
 192         .mmu.flush_tlb_one_user = native_flush_tlb_one_user,
 193         .mmu.flush_tlb_multi    = native_flush_tlb_multi,
 194         .mmu.tlb_remove_table   = native_tlb_remove_table,
 195
 196         .mmu.exit_mmap          = paravirt_nop,
 197         .mmu.notify_page_enc_status_changed     = paravirt_nop,
 198
 199 #ifdef CONFIG_PARAVIRT_XXL
 200         .mmu.read_cr2           = __PV_IS_CALLEE_SAVE(pv_native_read_cr2),
 201         .mmu.write_cr2          = pv_native_write_cr2,
 202         .mmu.read_cr3           = __native_read_cr3,
 203         .mmu.write_cr3          = native_write_cr3,
 204
 205         .mmu.pgd_alloc          = __paravirt_pgd_alloc,
 206         .mmu.pgd_free           = paravirt_nop,
 207
 208         .mmu.alloc_pte          = paravirt_nop,
 209         .mmu.alloc_pmd          = paravirt_nop,
 210         .mmu.alloc_pud          = paravirt_nop,
 211         .mmu.alloc_p4d          = paravirt_nop,
 212         .mmu.release_pte        = paravirt_nop,
 213         .mmu.release_pmd        = paravirt_nop,
 214         .mmu.release_pud        = paravirt_nop,
 215         .mmu.release_p4d        = paravirt_nop,
 216
 217         .mmu.set_pte            = native_set_pte,
 218         .mmu.set_pmd            = native_set_pmd,
 219
 220         .mmu.ptep_modify_prot_start     = __ptep_modify_prot_start,
 221         .mmu.ptep_modify_prot_commit    = __ptep_modify_prot_commit,
 222
 223         .mmu.set_pud            = native_set_pud,
 224
 225         .mmu.pmd_val            = PTE_IDENT,
 226         .mmu.make_pmd           = PTE_IDENT,
 227
 228         .mmu.pud_val            = PTE_IDENT,
 229         .mmu.make_pud           = PTE_IDENT,
 230
 231         .mmu.set_p4d            = native_set_p4d,
 232
 233 #if CONFIG_PGTABLE_LEVELS >= 5
 234         .mmu.p4d_val            = PTE_IDENT,
 235         .mmu.make_p4d           = PTE_IDENT,
 236
 237         .mmu.set_pgd            = native_set_pgd,
 238 #endif /* CONFIG_PGTABLE_LEVELS >= 5 */
 239
 240         .mmu.pte_val            = PTE_IDENT,
 241         .mmu.pgd_val            = PTE_IDENT,
 242
 243         .mmu.make_pte           = PTE_IDENT,
 244         .mmu.make_pgd           = PTE_IDENT,
 245
 246         .mmu.enter_mmap         = paravirt_nop,
 247
 248         .mmu.lazy_mode = {
 249                 .enter          = paravirt_nop,
 250                 .leave          = paravirt_nop,
 251                 .flush          = paravirt_nop,
 252         },
 253
 254         .mmu.set_fixmap         = native_set_fixmap,
 255 #endif /* CONFIG_PARAVIRT_XXL */
 256
 257 #if defined(CONFIG_PARAVIRT_SPINLOCKS)
 258         /* Lock ops. */
 259 #ifdef CONFIG_SMP
 260         .lock.queued_spin_lock_slowpath = native_queued_spin_lock_slowpath,
 261         .lock.queued_spin_unlock        =
 262                                 PV_CALLEE_SAVE(__native_queued_spin_unlock),
 263         .lock.wait                      = paravirt_nop,
 264         .lock.kick                      = paravirt_nop,
 265         .lock.vcpu_is_preempted         =
 266                                 PV_CALLEE_SAVE(__native_vcpu_is_preempted),
 267 #endif /* SMP */
 268 #endif
 269 };
 270
 271 #ifdef CONFIG_PARAVIRT_XXL
 272 NOKPROBE_SYMBOL(native_load_idt);
 273 #endif
 274
 275 EXPORT_SYMBOL(pv_ops);
 276 EXPORT_SYMBOL_GPL(pv_info);