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 36 /* 37 * nop stub, which must not clobber anything *including the stack* to 38 * avoid confusing the entry prologues. 39 */ 40 extern void _paravirt_nop(void); 41 asm (".pushsection .entry.text, \"ax\"\n" 42 ".global _paravirt_nop\n" 43 "_paravirt_nop:\n\t" 44 ASM_ENDBR 45 ASM_RET 46 ".size _paravirt_nop, . - _paravirt_nop\n\t" 47 ".type _paravirt_nop, @function\n\t" 48 ".popsection"); 49 50 /* stub always returning 0. */ 51 asm (".pushsection .entry.text, \"ax\"\n" 52 ".global paravirt_ret0\n" 53 "paravirt_ret0:\n\t" 54 ASM_ENDBR 55 "xor %" _ASM_AX ", %" _ASM_AX ";\n\t" 56 ASM_RET 57 ".size paravirt_ret0, . - paravirt_ret0\n\t" 58 ".type paravirt_ret0, @function\n\t" 59 ".popsection"); 60 61 62 void __init default_banner(void) 63 { 64 printk(KERN_INFO "Booting paravirtualized kernel on %s\n", 65 pv_info.name); 66 } 67 68 /* Undefined instruction for dealing with missing ops pointers. */ 69 noinstr void paravirt_BUG(void) 70 { 71 BUG(); 72 } 73 74 static unsigned paravirt_patch_call(void *insn_buff, const void *target, 75 unsigned long addr, unsigned len) 76 { 77 __text_gen_insn(insn_buff, CALL_INSN_OPCODE, 78 (void *)addr, target, CALL_INSN_SIZE); 79 return CALL_INSN_SIZE; 80 } 81 82 #ifdef CONFIG_PARAVIRT_XXL 83 /* identity function, which can be inlined */ 84 u64 notrace _paravirt_ident_64(u64 x) 85 { 86 return x; 87 } 88 #endif 89 90 DEFINE_STATIC_KEY_TRUE(virt_spin_lock_key); 91 92 void __init native_pv_lock_init(void) 93 { 94 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR)) 95 static_branch_disable(&virt_spin_lock_key); 96 } 97 98 unsigned int paravirt_patch(u8 type, void *insn_buff, unsigned long addr, 99 unsigned int len) 100 { 101 /* 102 * Neat trick to map patch type back to the call within the 103 * corresponding structure. 104 */ 105 void *opfunc = *((void **)&pv_ops + type); 106 unsigned ret; 107 108 if (opfunc == NULL) 109 /* If there's no function, patch it with paravirt_BUG() */ 110 ret = paravirt_patch_call(insn_buff, paravirt_BUG, addr, len); 111 else if (opfunc == _paravirt_nop) 112 ret = 0; 113 else 114 /* Otherwise call the function. */ 115 ret = paravirt_patch_call(insn_buff, opfunc, addr, len); 116 117 return ret; 118 } 119 120 struct static_key paravirt_steal_enabled; 121 struct static_key paravirt_steal_rq_enabled; 122 123 static u64 native_steal_clock(int cpu) 124 { 125 return 0; 126 } 127 128 DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock); 129 DEFINE_STATIC_CALL(pv_sched_clock, native_sched_clock); 130 131 void paravirt_set_sched_clock(u64 (*func)(void)) 132 { 133 static_call_update(pv_sched_clock, func); 134 } 135 136 /* These are in entry.S */ 137 static struct resource reserve_ioports = { 138 .start = 0, 139 .end = IO_SPACE_LIMIT, 140 .name = "paravirt-ioport", 141 .flags = IORESOURCE_IO | IORESOURCE_BUSY, 142 }; 143 144 /* 145 * Reserve the whole legacy IO space to prevent any legacy drivers 146 * from wasting time probing for their hardware. This is a fairly 147 * brute-force approach to disabling all non-virtual drivers. 148 * 149 * Note that this must be called very early to have any effect. 150 */ 151 int paravirt_disable_iospace(void) 152 { 153 return request_resource(&ioport_resource, &reserve_ioports); 154 } 155 156 static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE; 157 158 static inline void enter_lazy(enum paravirt_lazy_mode mode) 159 { 160 BUG_ON(this_cpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE); 161 162 this_cpu_write(paravirt_lazy_mode, mode); 163 } 164 165 static void leave_lazy(enum paravirt_lazy_mode mode) 166 { 167 BUG_ON(this_cpu_read(paravirt_lazy_mode) != mode); 168 169 this_cpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE); 170 } 171 172 void paravirt_enter_lazy_mmu(void) 173 { 174 enter_lazy(PARAVIRT_LAZY_MMU); 175 } 176 177 void paravirt_leave_lazy_mmu(void) 178 { 179 leave_lazy(PARAVIRT_LAZY_MMU); 180 } 181 182 void paravirt_flush_lazy_mmu(void) 183 { 184 preempt_disable(); 185 186 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) { 187 arch_leave_lazy_mmu_mode(); 188 arch_enter_lazy_mmu_mode(); 189 } 190 191 preempt_enable(); 192 } 193 194 #ifdef CONFIG_PARAVIRT_XXL 195 void paravirt_start_context_switch(struct task_struct *prev) 196 { 197 BUG_ON(preemptible()); 198 199 if (this_cpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) { 200 arch_leave_lazy_mmu_mode(); 201 set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES); 202 } 203 enter_lazy(PARAVIRT_LAZY_CPU); 204 } 205 206 void paravirt_end_context_switch(struct task_struct *next) 207 { 208 BUG_ON(preemptible()); 209 210 leave_lazy(PARAVIRT_LAZY_CPU); 211 212 if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES)) 213 arch_enter_lazy_mmu_mode(); 214 } 215 216 static noinstr unsigned long pv_native_read_cr2(void) 217 { 218 return native_read_cr2(); 219 } 220 221 static noinstr void pv_native_write_cr2(unsigned long val) 222 { 223 native_write_cr2(val); 224 } 225 226 static noinstr unsigned long pv_native_get_debugreg(int regno) 227 { 228 return native_get_debugreg(regno); 229 } 230 231 static noinstr void pv_native_set_debugreg(int regno, unsigned long val) 232 { 233 native_set_debugreg(regno, val); 234 } 235 236 static noinstr void pv_native_irq_enable(void) 237 { 238 native_irq_enable(); 239 } 240 241 static noinstr void pv_native_irq_disable(void) 242 { 243 native_irq_disable(); 244 } 245 #endif 246 247 enum paravirt_lazy_mode paravirt_get_lazy_mode(void) 248 { 249 if (in_interrupt()) 250 return PARAVIRT_LAZY_NONE; 251 252 return this_cpu_read(paravirt_lazy_mode); 253 } 254 255 struct pv_info pv_info = { 256 .name = "bare hardware", 257 #ifdef CONFIG_PARAVIRT_XXL 258 .extra_user_64bit_cs = __USER_CS, 259 #endif 260 }; 261 262 /* 64-bit pagetable entries */ 263 #define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_64) 264 265 struct paravirt_patch_template pv_ops = { 266 /* Cpu ops. */ 267 .cpu.io_delay = native_io_delay, 268 269 #ifdef CONFIG_PARAVIRT_XXL 270 .cpu.cpuid = native_cpuid, 271 .cpu.get_debugreg = pv_native_get_debugreg, 272 .cpu.set_debugreg = pv_native_set_debugreg, 273 .cpu.read_cr0 = native_read_cr0, 274 .cpu.write_cr0 = native_write_cr0, 275 .cpu.write_cr4 = native_write_cr4, 276 .cpu.wbinvd = native_wbinvd, 277 .cpu.read_msr = native_read_msr, 278 .cpu.write_msr = native_write_msr, 279 .cpu.read_msr_safe = native_read_msr_safe, 280 .cpu.write_msr_safe = native_write_msr_safe, 281 .cpu.read_pmc = native_read_pmc, 282 .cpu.load_tr_desc = native_load_tr_desc, 283 .cpu.set_ldt = native_set_ldt, 284 .cpu.load_gdt = native_load_gdt, 285 .cpu.load_idt = native_load_idt, 286 .cpu.store_tr = native_store_tr, 287 .cpu.load_tls = native_load_tls, 288 .cpu.load_gs_index = native_load_gs_index, 289 .cpu.write_ldt_entry = native_write_ldt_entry, 290 .cpu.write_gdt_entry = native_write_gdt_entry, 291 .cpu.write_idt_entry = native_write_idt_entry, 292 293 .cpu.alloc_ldt = paravirt_nop, 294 .cpu.free_ldt = paravirt_nop, 295 296 .cpu.load_sp0 = native_load_sp0, 297 298 #ifdef CONFIG_X86_IOPL_IOPERM 299 .cpu.invalidate_io_bitmap = native_tss_invalidate_io_bitmap, 300 .cpu.update_io_bitmap = native_tss_update_io_bitmap, 301 #endif 302 303 .cpu.start_context_switch = paravirt_nop, 304 .cpu.end_context_switch = paravirt_nop, 305 306 /* Irq ops. */ 307 .irq.save_fl = __PV_IS_CALLEE_SAVE(native_save_fl), 308 .irq.irq_disable = __PV_IS_CALLEE_SAVE(pv_native_irq_disable), 309 .irq.irq_enable = __PV_IS_CALLEE_SAVE(pv_native_irq_enable), 310 .irq.safe_halt = native_safe_halt, 311 .irq.halt = native_halt, 312 #endif /* CONFIG_PARAVIRT_XXL */ 313 314 /* Mmu ops. */ 315 .mmu.flush_tlb_user = native_flush_tlb_local, 316 .mmu.flush_tlb_kernel = native_flush_tlb_global, 317 .mmu.flush_tlb_one_user = native_flush_tlb_one_user, 318 .mmu.flush_tlb_multi = native_flush_tlb_multi, 319 .mmu.tlb_remove_table = 320 (void (*)(struct mmu_gather *, void *))tlb_remove_page, 321 322 .mmu.exit_mmap = paravirt_nop, 323 .mmu.notify_page_enc_status_changed = paravirt_nop, 324 325 #ifdef CONFIG_PARAVIRT_XXL 326 .mmu.read_cr2 = __PV_IS_CALLEE_SAVE(pv_native_read_cr2), 327 .mmu.write_cr2 = pv_native_write_cr2, 328 .mmu.read_cr3 = __native_read_cr3, 329 .mmu.write_cr3 = native_write_cr3, 330 331 .mmu.pgd_alloc = __paravirt_pgd_alloc, 332 .mmu.pgd_free = paravirt_nop, 333 334 .mmu.alloc_pte = paravirt_nop, 335 .mmu.alloc_pmd = paravirt_nop, 336 .mmu.alloc_pud = paravirt_nop, 337 .mmu.alloc_p4d = paravirt_nop, 338 .mmu.release_pte = paravirt_nop, 339 .mmu.release_pmd = paravirt_nop, 340 .mmu.release_pud = paravirt_nop, 341 .mmu.release_p4d = paravirt_nop, 342 343 .mmu.set_pte = native_set_pte, 344 .mmu.set_pmd = native_set_pmd, 345 346 .mmu.ptep_modify_prot_start = __ptep_modify_prot_start, 347 .mmu.ptep_modify_prot_commit = __ptep_modify_prot_commit, 348 349 .mmu.set_pud = native_set_pud, 350 351 .mmu.pmd_val = PTE_IDENT, 352 .mmu.make_pmd = PTE_IDENT, 353 354 .mmu.pud_val = PTE_IDENT, 355 .mmu.make_pud = PTE_IDENT, 356 357 .mmu.set_p4d = native_set_p4d, 358 359 #if CONFIG_PGTABLE_LEVELS >= 5 360 .mmu.p4d_val = PTE_IDENT, 361 .mmu.make_p4d = PTE_IDENT, 362 363 .mmu.set_pgd = native_set_pgd, 364 #endif /* CONFIG_PGTABLE_LEVELS >= 5 */ 365 366 .mmu.pte_val = PTE_IDENT, 367 .mmu.pgd_val = PTE_IDENT, 368 369 .mmu.make_pte = PTE_IDENT, 370 .mmu.make_pgd = PTE_IDENT, 371 372 .mmu.dup_mmap = paravirt_nop, 373 .mmu.activate_mm = paravirt_nop, 374 375 .mmu.lazy_mode = { 376 .enter = paravirt_nop, 377 .leave = paravirt_nop, 378 .flush = paravirt_nop, 379 }, 380 381 .mmu.set_fixmap = native_set_fixmap, 382 #endif /* CONFIG_PARAVIRT_XXL */ 383 384 #if defined(CONFIG_PARAVIRT_SPINLOCKS) 385 /* Lock ops. */ 386 #ifdef CONFIG_SMP 387 .lock.queued_spin_lock_slowpath = native_queued_spin_lock_slowpath, 388 .lock.queued_spin_unlock = 389 PV_CALLEE_SAVE(__native_queued_spin_unlock), 390 .lock.wait = paravirt_nop, 391 .lock.kick = paravirt_nop, 392 .lock.vcpu_is_preempted = 393 PV_CALLEE_SAVE(__native_vcpu_is_preempted), 394 #endif /* SMP */ 395 #endif 396 }; 397 398 #ifdef CONFIG_PARAVIRT_XXL 399 NOKPROBE_SYMBOL(native_load_idt); 400 #endif 401 402 EXPORT_SYMBOL(pv_ops); 403 EXPORT_SYMBOL_GPL(pv_info); 404