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 /* 38 * nop stub, which must not clobber anything *including the stack* to 39 * avoid confusing the entry prologues. 40 */ 41 DEFINE_PARAVIRT_ASM(_paravirt_nop, "", .entry.text); 42 43 /* stub always returning 0. */ 44 DEFINE_PARAVIRT_ASM(paravirt_ret0, "xor %eax,%eax", .entry.text); 45 46 void __init default_banner(void) 47 { 48 printk(KERN_INFO "Booting paravirtualized kernel on %s\n", 49 pv_info.name); 50 } 51 52 /* Undefined instruction for dealing with missing ops pointers. */ 53 noinstr void paravirt_BUG(void) 54 { 55 BUG(); 56 } 57 58 static unsigned paravirt_patch_call(void *insn_buff, const void *target, 59 unsigned long addr, unsigned len) 60 { 61 __text_gen_insn(insn_buff, CALL_INSN_OPCODE, 62 (void *)addr, target, CALL_INSN_SIZE); 63 return CALL_INSN_SIZE; 64 } 65 66 #ifdef CONFIG_PARAVIRT_XXL 67 DEFINE_PARAVIRT_ASM(_paravirt_ident_64, "mov %rdi, %rax", .text); 68 DEFINE_PARAVIRT_ASM(pv_native_save_fl, "pushf; pop %rax", .noinstr.text); 69 DEFINE_PARAVIRT_ASM(pv_native_irq_disable, "cli", .noinstr.text); 70 DEFINE_PARAVIRT_ASM(pv_native_irq_enable, "sti", .noinstr.text); 71 DEFINE_PARAVIRT_ASM(pv_native_read_cr2, "mov %cr2, %rax", .noinstr.text); 72 #endif 73 74 DEFINE_STATIC_KEY_TRUE(virt_spin_lock_key); 75 76 void __init native_pv_lock_init(void) 77 { 78 if (IS_ENABLED(CONFIG_PARAVIRT_SPINLOCKS) && 79 !boot_cpu_has(X86_FEATURE_HYPERVISOR)) 80 static_branch_disable(&virt_spin_lock_key); 81 } 82 83 static void native_tlb_remove_table(struct mmu_gather *tlb, void *table) 84 { 85 tlb_remove_page(tlb, table); 86 } 87 88 unsigned int paravirt_patch(u8 type, void *insn_buff, unsigned long addr, 89 unsigned int len) 90 { 91 /* 92 * Neat trick to map patch type back to the call within the 93 * corresponding structure. 94 */ 95 void *opfunc = *((void **)&pv_ops + type); 96 unsigned ret; 97 98 if (opfunc == NULL) 99 /* If there's no function, patch it with paravirt_BUG() */ 100 ret = paravirt_patch_call(insn_buff, paravirt_BUG, addr, len); 101 else if (opfunc == _paravirt_nop) 102 ret = 0; 103 else 104 /* Otherwise call the function. */ 105 ret = paravirt_patch_call(insn_buff, opfunc, addr, len); 106 107 return ret; 108 } 109 110 struct static_key paravirt_steal_enabled; 111 struct static_key paravirt_steal_rq_enabled; 112 113 static u64 native_steal_clock(int cpu) 114 { 115 return 0; 116 } 117 118 DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock); 119 DEFINE_STATIC_CALL(pv_sched_clock, native_sched_clock); 120 121 void paravirt_set_sched_clock(u64 (*func)(void)) 122 { 123 static_call_update(pv_sched_clock, func); 124 } 125 126 /* These are in entry.S */ 127 static struct resource reserve_ioports = { 128 .start = 0, 129 .end = IO_SPACE_LIMIT, 130 .name = "paravirt-ioport", 131 .flags = IORESOURCE_IO | IORESOURCE_BUSY, 132 }; 133 134 /* 135 * Reserve the whole legacy IO space to prevent any legacy drivers 136 * from wasting time probing for their hardware. This is a fairly 137 * brute-force approach to disabling all non-virtual drivers. 138 * 139 * Note that this must be called very early to have any effect. 140 */ 141 int paravirt_disable_iospace(void) 142 { 143 return request_resource(&ioport_resource, &reserve_ioports); 144 } 145 146 static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE; 147 148 static inline void enter_lazy(enum paravirt_lazy_mode mode) 149 { 150 BUG_ON(this_cpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE); 151 152 this_cpu_write(paravirt_lazy_mode, mode); 153 } 154 155 static void leave_lazy(enum paravirt_lazy_mode mode) 156 { 157 BUG_ON(this_cpu_read(paravirt_lazy_mode) != mode); 158 159 this_cpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE); 160 } 161 162 void paravirt_enter_lazy_mmu(void) 163 { 164 enter_lazy(PARAVIRT_LAZY_MMU); 165 } 166 167 void paravirt_leave_lazy_mmu(void) 168 { 169 leave_lazy(PARAVIRT_LAZY_MMU); 170 } 171 172 void paravirt_flush_lazy_mmu(void) 173 { 174 preempt_disable(); 175 176 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) { 177 arch_leave_lazy_mmu_mode(); 178 arch_enter_lazy_mmu_mode(); 179 } 180 181 preempt_enable(); 182 } 183 184 #ifdef CONFIG_PARAVIRT_XXL 185 void paravirt_start_context_switch(struct task_struct *prev) 186 { 187 BUG_ON(preemptible()); 188 189 if (this_cpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) { 190 arch_leave_lazy_mmu_mode(); 191 set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES); 192 } 193 enter_lazy(PARAVIRT_LAZY_CPU); 194 } 195 196 void paravirt_end_context_switch(struct task_struct *next) 197 { 198 BUG_ON(preemptible()); 199 200 leave_lazy(PARAVIRT_LAZY_CPU); 201 202 if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES)) 203 arch_enter_lazy_mmu_mode(); 204 } 205 206 static noinstr void pv_native_write_cr2(unsigned long val) 207 { 208 native_write_cr2(val); 209 } 210 211 static noinstr unsigned long pv_native_get_debugreg(int regno) 212 { 213 return native_get_debugreg(regno); 214 } 215 216 static noinstr void pv_native_set_debugreg(int regno, unsigned long val) 217 { 218 native_set_debugreg(regno, val); 219 } 220 221 noinstr void pv_native_wbinvd(void) 222 { 223 native_wbinvd(); 224 } 225 226 static noinstr void pv_native_safe_halt(void) 227 { 228 native_safe_halt(); 229 } 230 #endif 231 232 enum paravirt_lazy_mode paravirt_get_lazy_mode(void) 233 { 234 if (in_interrupt()) 235 return PARAVIRT_LAZY_NONE; 236 237 return this_cpu_read(paravirt_lazy_mode); 238 } 239 240 struct pv_info pv_info = { 241 .name = "bare hardware", 242 #ifdef CONFIG_PARAVIRT_XXL 243 .extra_user_64bit_cs = __USER_CS, 244 #endif 245 }; 246 247 /* 64-bit pagetable entries */ 248 #define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_64) 249 250 struct paravirt_patch_template pv_ops = { 251 /* Cpu ops. */ 252 .cpu.io_delay = native_io_delay, 253 254 #ifdef CONFIG_PARAVIRT_XXL 255 .cpu.cpuid = native_cpuid, 256 .cpu.get_debugreg = pv_native_get_debugreg, 257 .cpu.set_debugreg = pv_native_set_debugreg, 258 .cpu.read_cr0 = native_read_cr0, 259 .cpu.write_cr0 = native_write_cr0, 260 .cpu.write_cr4 = native_write_cr4, 261 .cpu.wbinvd = pv_native_wbinvd, 262 .cpu.read_msr = native_read_msr, 263 .cpu.write_msr = native_write_msr, 264 .cpu.read_msr_safe = native_read_msr_safe, 265 .cpu.write_msr_safe = native_write_msr_safe, 266 .cpu.read_pmc = native_read_pmc, 267 .cpu.load_tr_desc = native_load_tr_desc, 268 .cpu.set_ldt = native_set_ldt, 269 .cpu.load_gdt = native_load_gdt, 270 .cpu.load_idt = native_load_idt, 271 .cpu.store_tr = native_store_tr, 272 .cpu.load_tls = native_load_tls, 273 .cpu.load_gs_index = native_load_gs_index, 274 .cpu.write_ldt_entry = native_write_ldt_entry, 275 .cpu.write_gdt_entry = native_write_gdt_entry, 276 .cpu.write_idt_entry = native_write_idt_entry, 277 278 .cpu.alloc_ldt = paravirt_nop, 279 .cpu.free_ldt = paravirt_nop, 280 281 .cpu.load_sp0 = native_load_sp0, 282 283 #ifdef CONFIG_X86_IOPL_IOPERM 284 .cpu.invalidate_io_bitmap = native_tss_invalidate_io_bitmap, 285 .cpu.update_io_bitmap = native_tss_update_io_bitmap, 286 #endif 287 288 .cpu.start_context_switch = paravirt_nop, 289 .cpu.end_context_switch = paravirt_nop, 290 291 /* Irq ops. */ 292 .irq.save_fl = __PV_IS_CALLEE_SAVE(pv_native_save_fl), 293 .irq.irq_disable = __PV_IS_CALLEE_SAVE(pv_native_irq_disable), 294 .irq.irq_enable = __PV_IS_CALLEE_SAVE(pv_native_irq_enable), 295 .irq.safe_halt = pv_native_safe_halt, 296 .irq.halt = native_halt, 297 #endif /* CONFIG_PARAVIRT_XXL */ 298 299 /* Mmu ops. */ 300 .mmu.flush_tlb_user = native_flush_tlb_local, 301 .mmu.flush_tlb_kernel = native_flush_tlb_global, 302 .mmu.flush_tlb_one_user = native_flush_tlb_one_user, 303 .mmu.flush_tlb_multi = native_flush_tlb_multi, 304 .mmu.tlb_remove_table = native_tlb_remove_table, 305 306 .mmu.exit_mmap = paravirt_nop, 307 .mmu.notify_page_enc_status_changed = paravirt_nop, 308 309 #ifdef CONFIG_PARAVIRT_XXL 310 .mmu.read_cr2 = __PV_IS_CALLEE_SAVE(pv_native_read_cr2), 311 .mmu.write_cr2 = pv_native_write_cr2, 312 .mmu.read_cr3 = __native_read_cr3, 313 .mmu.write_cr3 = native_write_cr3, 314 315 .mmu.pgd_alloc = __paravirt_pgd_alloc, 316 .mmu.pgd_free = paravirt_nop, 317 318 .mmu.alloc_pte = paravirt_nop, 319 .mmu.alloc_pmd = paravirt_nop, 320 .mmu.alloc_pud = paravirt_nop, 321 .mmu.alloc_p4d = paravirt_nop, 322 .mmu.release_pte = paravirt_nop, 323 .mmu.release_pmd = paravirt_nop, 324 .mmu.release_pud = paravirt_nop, 325 .mmu.release_p4d = paravirt_nop, 326 327 .mmu.set_pte = native_set_pte, 328 .mmu.set_pmd = native_set_pmd, 329 330 .mmu.ptep_modify_prot_start = __ptep_modify_prot_start, 331 .mmu.ptep_modify_prot_commit = __ptep_modify_prot_commit, 332 333 .mmu.set_pud = native_set_pud, 334 335 .mmu.pmd_val = PTE_IDENT, 336 .mmu.make_pmd = PTE_IDENT, 337 338 .mmu.pud_val = PTE_IDENT, 339 .mmu.make_pud = PTE_IDENT, 340 341 .mmu.set_p4d = native_set_p4d, 342 343 #if CONFIG_PGTABLE_LEVELS >= 5 344 .mmu.p4d_val = PTE_IDENT, 345 .mmu.make_p4d = PTE_IDENT, 346 347 .mmu.set_pgd = native_set_pgd, 348 #endif /* CONFIG_PGTABLE_LEVELS >= 5 */ 349 350 .mmu.pte_val = PTE_IDENT, 351 .mmu.pgd_val = PTE_IDENT, 352 353 .mmu.make_pte = PTE_IDENT, 354 .mmu.make_pgd = PTE_IDENT, 355 356 .mmu.enter_mmap = paravirt_nop, 357 358 .mmu.lazy_mode = { 359 .enter = paravirt_nop, 360 .leave = paravirt_nop, 361 .flush = paravirt_nop, 362 }, 363 364 .mmu.set_fixmap = native_set_fixmap, 365 #endif /* CONFIG_PARAVIRT_XXL */ 366 367 #if defined(CONFIG_PARAVIRT_SPINLOCKS) 368 /* Lock ops. */ 369 #ifdef CONFIG_SMP 370 .lock.queued_spin_lock_slowpath = native_queued_spin_lock_slowpath, 371 .lock.queued_spin_unlock = 372 PV_CALLEE_SAVE(__native_queued_spin_unlock), 373 .lock.wait = paravirt_nop, 374 .lock.kick = paravirt_nop, 375 .lock.vcpu_is_preempted = 376 PV_CALLEE_SAVE(__native_vcpu_is_preempted), 377 #endif /* SMP */ 378 #endif 379 }; 380 381 #ifdef CONFIG_PARAVIRT_XXL 382 NOKPROBE_SYMBOL(native_load_idt); 383 #endif 384 385 EXPORT_SYMBOL(pv_ops); 386 EXPORT_SYMBOL_GPL(pv_info); 387