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_TRUE(virt_spin_lock_key);
  55
  56 void __init native_pv_lock_init(void)
  57 {
  58         if (IS_ENABLED(CONFIG_PARAVIRT_SPINLOCKS) &&
  59             !boot_cpu_has(X86_FEATURE_HYPERVISOR))
  60                 static_branch_disable(&virt_spin_lock_key);
  61 }
  62
  63 static void native_tlb_remove_table(struct mmu_gather *tlb, void *table)
  64 {
  65         tlb_remove_page(tlb, table);
  66 }
  67
  68 struct static_key paravirt_steal_enabled;
  69 struct static_key paravirt_steal_rq_enabled;
  70
  71 static u64 native_steal_clock(int cpu)
  72 {
  73         return 0;
  74 }
  75
  76 DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock);
  77 DEFINE_STATIC_CALL(pv_sched_clock, native_sched_clock);
  78
  79 void paravirt_set_sched_clock(u64 (*func)(void))
  80 {
  81         static_call_update(pv_sched_clock, func);
  82 }
  83
  84 /* These are in entry.S */
  85 static struct resource reserve_ioports = {
  86         .start = 0,
  87         .end = IO_SPACE_LIMIT,
  88         .name = "paravirt-ioport",
  89         .flags = IORESOURCE_IO | IORESOURCE_BUSY,
  90 };
  91
  92 /*
  93  * Reserve the whole legacy IO space to prevent any legacy drivers
  94  * from wasting time probing for their hardware.  This is a fairly
  95  * brute-force approach to disabling all non-virtual drivers.
  96  *
  97  * Note that this must be called very early to have any effect.
  98  */
  99 int paravirt_disable_iospace(void)
 100 {
 101         return request_resource(&ioport_resource, &reserve_ioports);
 102 }
 103
 104 #ifdef CONFIG_PARAVIRT_XXL
 105 static noinstr void pv_native_write_cr2(unsigned long val)
 106 {
 107         native_write_cr2(val);
 108 }
 109
 110 static noinstr unsigned long pv_native_get_debugreg(int regno)
 111 {
 112         return native_get_debugreg(regno);
 113 }
 114
 115 static noinstr void pv_native_set_debugreg(int regno, unsigned long val)
 116 {
 117         native_set_debugreg(regno, val);
 118 }
 119
 120 noinstr void pv_native_wbinvd(void)
 121 {
 122         native_wbinvd();
 123 }
 124
 125 static noinstr void pv_native_safe_halt(void)
 126 {
 127         native_safe_halt();
 128 }
 129 #endif
 130
 131 struct pv_info pv_info = {
 132         .name = "bare hardware",
 133 #ifdef CONFIG_PARAVIRT_XXL
 134         .extra_user_64bit_cs = __USER_CS,
 135 #endif
 136 };
 137
 138 /* 64-bit pagetable entries */
 139 #define PTE_IDENT       __PV_IS_CALLEE_SAVE(_paravirt_ident_64)
 140
 141 struct paravirt_patch_template pv_ops = {
 142         /* Cpu ops. */
 143         .cpu.io_delay           = native_io_delay,
 144
 145 #ifdef CONFIG_PARAVIRT_XXL
 146         .cpu.cpuid              = native_cpuid,
 147         .cpu.get_debugreg       = pv_native_get_debugreg,
 148         .cpu.set_debugreg       = pv_native_set_debugreg,
 149         .cpu.read_cr0           = native_read_cr0,
 150         .cpu.write_cr0          = native_write_cr0,
 151         .cpu.write_cr4          = native_write_cr4,
 152         .cpu.wbinvd             = pv_native_wbinvd,
 153         .cpu.read_msr           = native_read_msr,
 154         .cpu.write_msr          = native_write_msr,
 155         .cpu.read_msr_safe      = native_read_msr_safe,
 156         .cpu.write_msr_safe     = native_write_msr_safe,
 157         .cpu.read_pmc           = native_read_pmc,
 158         .cpu.load_tr_desc       = native_load_tr_desc,
 159         .cpu.set_ldt            = native_set_ldt,
 160         .cpu.load_gdt           = native_load_gdt,
 161         .cpu.load_idt           = native_load_idt,
 162         .cpu.store_tr           = native_store_tr,
 163         .cpu.load_tls           = native_load_tls,
 164         .cpu.load_gs_index      = native_load_gs_index,
 165         .cpu.write_ldt_entry    = native_write_ldt_entry,
 166         .cpu.write_gdt_entry    = native_write_gdt_entry,
 167         .cpu.write_idt_entry    = native_write_idt_entry,
 168
 169         .cpu.alloc_ldt          = paravirt_nop,
 170         .cpu.free_ldt           = paravirt_nop,
 171
 172         .cpu.load_sp0           = native_load_sp0,
 173
 174 #ifdef CONFIG_X86_IOPL_IOPERM
 175         .cpu.invalidate_io_bitmap       = native_tss_invalidate_io_bitmap,
 176         .cpu.update_io_bitmap           = native_tss_update_io_bitmap,
 177 #endif
 178
 179         .cpu.start_context_switch       = paravirt_nop,
 180         .cpu.end_context_switch         = paravirt_nop,
 181
 182         /* Irq ops. */
 183         .irq.save_fl            = __PV_IS_CALLEE_SAVE(pv_native_save_fl),
 184         .irq.irq_disable        = __PV_IS_CALLEE_SAVE(pv_native_irq_disable),
 185         .irq.irq_enable         = __PV_IS_CALLEE_SAVE(pv_native_irq_enable),
 186         .irq.safe_halt          = pv_native_safe_halt,
 187         .irq.halt               = native_halt,
 188 #endif /* CONFIG_PARAVIRT_XXL */
 189
 190         /* Mmu ops. */
 191         .mmu.flush_tlb_user     = native_flush_tlb_local,
 192         .mmu.flush_tlb_kernel   = native_flush_tlb_global,
 193         .mmu.flush_tlb_one_user = native_flush_tlb_one_user,
 194         .mmu.flush_tlb_multi    = native_flush_tlb_multi,
 195         .mmu.tlb_remove_table   = native_tlb_remove_table,
 196
 197         .mmu.exit_mmap          = paravirt_nop,
 198         .mmu.notify_page_enc_status_changed     = paravirt_nop,
 199
 200 #ifdef CONFIG_PARAVIRT_XXL
 201         .mmu.read_cr2           = __PV_IS_CALLEE_SAVE(pv_native_read_cr2),
 202         .mmu.write_cr2          = pv_native_write_cr2,
 203         .mmu.read_cr3           = __native_read_cr3,
 204         .mmu.write_cr3          = native_write_cr3,
 205
 206         .mmu.pgd_alloc          = __paravirt_pgd_alloc,
 207         .mmu.pgd_free           = paravirt_nop,
 208
 209         .mmu.alloc_pte          = paravirt_nop,
 210         .mmu.alloc_pmd          = paravirt_nop,
 211         .mmu.alloc_pud          = paravirt_nop,
 212         .mmu.alloc_p4d          = paravirt_nop,
 213         .mmu.release_pte        = paravirt_nop,
 214         .mmu.release_pmd        = paravirt_nop,
 215         .mmu.release_pud        = paravirt_nop,
 216         .mmu.release_p4d        = paravirt_nop,
 217
 218         .mmu.set_pte            = native_set_pte,
 219         .mmu.set_pmd            = native_set_pmd,
 220
 221         .mmu.ptep_modify_prot_start     = __ptep_modify_prot_start,
 222         .mmu.ptep_modify_prot_commit    = __ptep_modify_prot_commit,
 223
 224         .mmu.set_pud            = native_set_pud,
 225
 226         .mmu.pmd_val            = PTE_IDENT,
 227         .mmu.make_pmd           = PTE_IDENT,
 228
 229         .mmu.pud_val            = PTE_IDENT,
 230         .mmu.make_pud           = PTE_IDENT,
 231
 232         .mmu.set_p4d            = native_set_p4d,
 233
 234 #if CONFIG_PGTABLE_LEVELS >= 5
 235         .mmu.p4d_val            = PTE_IDENT,
 236         .mmu.make_p4d           = PTE_IDENT,
 237
 238         .mmu.set_pgd            = native_set_pgd,
 239 #endif /* CONFIG_PGTABLE_LEVELS >= 5 */
 240
 241         .mmu.pte_val            = PTE_IDENT,
 242         .mmu.pgd_val            = PTE_IDENT,
 243
 244         .mmu.make_pte           = PTE_IDENT,
 245         .mmu.make_pgd           = PTE_IDENT,
 246
 247         .mmu.enter_mmap         = paravirt_nop,
 248
 249         .mmu.lazy_mode = {
 250                 .enter          = paravirt_nop,
 251                 .leave          = paravirt_nop,
 252                 .flush          = paravirt_nop,
 253         },
 254
 255         .mmu.set_fixmap         = native_set_fixmap,
 256 #endif /* CONFIG_PARAVIRT_XXL */
 257
 258 #if defined(CONFIG_PARAVIRT_SPINLOCKS)
 259         /* Lock ops. */
 260 #ifdef CONFIG_SMP
 261         .lock.queued_spin_lock_slowpath = native_queued_spin_lock_slowpath,
 262         .lock.queued_spin_unlock        =
 263                                 PV_CALLEE_SAVE(__native_queued_spin_unlock),
 264         .lock.wait                      = paravirt_nop,
 265         .lock.kick                      = paravirt_nop,
 266         .lock.vcpu_is_preempted         =
 267                                 PV_CALLEE_SAVE(__native_vcpu_is_preempted),
 268 #endif /* SMP */
 269 #endif
 270 };
 271
 272 #ifdef CONFIG_PARAVIRT_XXL
 273 NOKPROBE_SYMBOL(native_load_idt);
 274 #endif
 275
 276 EXPORT_SYMBOL(pv_ops);
 277 EXPORT_SYMBOL_GPL(pv_info);