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 (!boot_cpu_has(X86_FEATURE_HYPERVISOR)) 79 static_branch_disable(&virt_spin_lock_key); 80 } 81 82 unsigned int paravirt_patch(u8 type, void *insn_buff, unsigned long addr, 83 unsigned int len) 84 { 85 /* 86 * Neat trick to map patch type back to the call within the 87 * corresponding structure. 88 */ 89 void *opfunc = *((void **)&pv_ops + type); 90 unsigned ret; 91 92 if (opfunc == NULL) 93 /* If there's no function, patch it with paravirt_BUG() */ 94 ret = paravirt_patch_call(insn_buff, paravirt_BUG, addr, len); 95 else if (opfunc == _paravirt_nop) 96 ret = 0; 97 else 98 /* Otherwise call the function. */ 99 ret = paravirt_patch_call(insn_buff, opfunc, addr, len); 100 101 return ret; 102 } 103 104 struct static_key paravirt_steal_enabled; 105 struct static_key paravirt_steal_rq_enabled; 106 107 static u64 native_steal_clock(int cpu) 108 { 109 return 0; 110 } 111 112 DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock); 113 DEFINE_STATIC_CALL(pv_sched_clock, native_sched_clock); 114 115 void paravirt_set_sched_clock(u64 (*func)(void)) 116 { 117 static_call_update(pv_sched_clock, func); 118 } 119 120 /* These are in entry.S */ 121 static struct resource reserve_ioports = { 122 .start = 0, 123 .end = IO_SPACE_LIMIT, 124 .name = "paravirt-ioport", 125 .flags = IORESOURCE_IO | IORESOURCE_BUSY, 126 }; 127 128 /* 129 * Reserve the whole legacy IO space to prevent any legacy drivers 130 * from wasting time probing for their hardware. This is a fairly 131 * brute-force approach to disabling all non-virtual drivers. 132 * 133 * Note that this must be called very early to have any effect. 134 */ 135 int paravirt_disable_iospace(void) 136 { 137 return request_resource(&ioport_resource, &reserve_ioports); 138 } 139 140 static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE; 141 142 static inline void enter_lazy(enum paravirt_lazy_mode mode) 143 { 144 BUG_ON(this_cpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE); 145 146 this_cpu_write(paravirt_lazy_mode, mode); 147 } 148 149 static void leave_lazy(enum paravirt_lazy_mode mode) 150 { 151 BUG_ON(this_cpu_read(paravirt_lazy_mode) != mode); 152 153 this_cpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE); 154 } 155 156 void paravirt_enter_lazy_mmu(void) 157 { 158 enter_lazy(PARAVIRT_LAZY_MMU); 159 } 160 161 void paravirt_leave_lazy_mmu(void) 162 { 163 leave_lazy(PARAVIRT_LAZY_MMU); 164 } 165 166 void paravirt_flush_lazy_mmu(void) 167 { 168 preempt_disable(); 169 170 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) { 171 arch_leave_lazy_mmu_mode(); 172 arch_enter_lazy_mmu_mode(); 173 } 174 175 preempt_enable(); 176 } 177 178 #ifdef CONFIG_PARAVIRT_XXL 179 void paravirt_start_context_switch(struct task_struct *prev) 180 { 181 BUG_ON(preemptible()); 182 183 if (this_cpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) { 184 arch_leave_lazy_mmu_mode(); 185 set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES); 186 } 187 enter_lazy(PARAVIRT_LAZY_CPU); 188 } 189 190 void paravirt_end_context_switch(struct task_struct *next) 191 { 192 BUG_ON(preemptible()); 193 194 leave_lazy(PARAVIRT_LAZY_CPU); 195 196 if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES)) 197 arch_enter_lazy_mmu_mode(); 198 } 199 200 static noinstr void pv_native_write_cr2(unsigned long val) 201 { 202 native_write_cr2(val); 203 } 204 205 static noinstr unsigned long pv_native_get_debugreg(int regno) 206 { 207 return native_get_debugreg(regno); 208 } 209 210 static noinstr void pv_native_set_debugreg(int regno, unsigned long val) 211 { 212 native_set_debugreg(regno, val); 213 } 214 215 noinstr void pv_native_wbinvd(void) 216 { 217 native_wbinvd(); 218 } 219 220 static noinstr void pv_native_safe_halt(void) 221 { 222 native_safe_halt(); 223 } 224 #endif 225 226 enum paravirt_lazy_mode paravirt_get_lazy_mode(void) 227 { 228 if (in_interrupt()) 229 return PARAVIRT_LAZY_NONE; 230 231 return this_cpu_read(paravirt_lazy_mode); 232 } 233 234 struct pv_info pv_info = { 235 .name = "bare hardware", 236 #ifdef CONFIG_PARAVIRT_XXL 237 .extra_user_64bit_cs = __USER_CS, 238 #endif 239 }; 240 241 /* 64-bit pagetable entries */ 242 #define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_64) 243 244 struct paravirt_patch_template pv_ops = { 245 /* Cpu ops. */ 246 .cpu.io_delay = native_io_delay, 247 248 #ifdef CONFIG_PARAVIRT_XXL 249 .cpu.cpuid = native_cpuid, 250 .cpu.get_debugreg = pv_native_get_debugreg, 251 .cpu.set_debugreg = pv_native_set_debugreg, 252 .cpu.read_cr0 = native_read_cr0, 253 .cpu.write_cr0 = native_write_cr0, 254 .cpu.write_cr4 = native_write_cr4, 255 .cpu.wbinvd = pv_native_wbinvd, 256 .cpu.read_msr = native_read_msr, 257 .cpu.write_msr = native_write_msr, 258 .cpu.read_msr_safe = native_read_msr_safe, 259 .cpu.write_msr_safe = native_write_msr_safe, 260 .cpu.read_pmc = native_read_pmc, 261 .cpu.load_tr_desc = native_load_tr_desc, 262 .cpu.set_ldt = native_set_ldt, 263 .cpu.load_gdt = native_load_gdt, 264 .cpu.load_idt = native_load_idt, 265 .cpu.store_tr = native_store_tr, 266 .cpu.load_tls = native_load_tls, 267 .cpu.load_gs_index = native_load_gs_index, 268 .cpu.write_ldt_entry = native_write_ldt_entry, 269 .cpu.write_gdt_entry = native_write_gdt_entry, 270 .cpu.write_idt_entry = native_write_idt_entry, 271 272 .cpu.alloc_ldt = paravirt_nop, 273 .cpu.free_ldt = paravirt_nop, 274 275 .cpu.load_sp0 = native_load_sp0, 276 277 #ifdef CONFIG_X86_IOPL_IOPERM 278 .cpu.invalidate_io_bitmap = native_tss_invalidate_io_bitmap, 279 .cpu.update_io_bitmap = native_tss_update_io_bitmap, 280 #endif 281 282 .cpu.start_context_switch = paravirt_nop, 283 .cpu.end_context_switch = paravirt_nop, 284 285 /* Irq ops. */ 286 .irq.save_fl = __PV_IS_CALLEE_SAVE(pv_native_save_fl), 287 .irq.irq_disable = __PV_IS_CALLEE_SAVE(pv_native_irq_disable), 288 .irq.irq_enable = __PV_IS_CALLEE_SAVE(pv_native_irq_enable), 289 .irq.safe_halt = pv_native_safe_halt, 290 .irq.halt = native_halt, 291 #endif /* CONFIG_PARAVIRT_XXL */ 292 293 /* Mmu ops. */ 294 .mmu.flush_tlb_user = native_flush_tlb_local, 295 .mmu.flush_tlb_kernel = native_flush_tlb_global, 296 .mmu.flush_tlb_one_user = native_flush_tlb_one_user, 297 .mmu.flush_tlb_multi = native_flush_tlb_multi, 298 .mmu.tlb_remove_table = 299 (void (*)(struct mmu_gather *, void *))tlb_remove_page, 300 301 .mmu.exit_mmap = paravirt_nop, 302 .mmu.notify_page_enc_status_changed = paravirt_nop, 303 304 #ifdef CONFIG_PARAVIRT_XXL 305 .mmu.read_cr2 = __PV_IS_CALLEE_SAVE(pv_native_read_cr2), 306 .mmu.write_cr2 = pv_native_write_cr2, 307 .mmu.read_cr3 = __native_read_cr3, 308 .mmu.write_cr3 = native_write_cr3, 309 310 .mmu.pgd_alloc = __paravirt_pgd_alloc, 311 .mmu.pgd_free = paravirt_nop, 312 313 .mmu.alloc_pte = paravirt_nop, 314 .mmu.alloc_pmd = paravirt_nop, 315 .mmu.alloc_pud = paravirt_nop, 316 .mmu.alloc_p4d = paravirt_nop, 317 .mmu.release_pte = paravirt_nop, 318 .mmu.release_pmd = paravirt_nop, 319 .mmu.release_pud = paravirt_nop, 320 .mmu.release_p4d = paravirt_nop, 321 322 .mmu.set_pte = native_set_pte, 323 .mmu.set_pmd = native_set_pmd, 324 325 .mmu.ptep_modify_prot_start = __ptep_modify_prot_start, 326 .mmu.ptep_modify_prot_commit = __ptep_modify_prot_commit, 327 328 .mmu.set_pud = native_set_pud, 329 330 .mmu.pmd_val = PTE_IDENT, 331 .mmu.make_pmd = PTE_IDENT, 332 333 .mmu.pud_val = PTE_IDENT, 334 .mmu.make_pud = PTE_IDENT, 335 336 .mmu.set_p4d = native_set_p4d, 337 338 #if CONFIG_PGTABLE_LEVELS >= 5 339 .mmu.p4d_val = PTE_IDENT, 340 .mmu.make_p4d = PTE_IDENT, 341 342 .mmu.set_pgd = native_set_pgd, 343 #endif /* CONFIG_PGTABLE_LEVELS >= 5 */ 344 345 .mmu.pte_val = PTE_IDENT, 346 .mmu.pgd_val = PTE_IDENT, 347 348 .mmu.make_pte = PTE_IDENT, 349 .mmu.make_pgd = PTE_IDENT, 350 351 .mmu.enter_mmap = paravirt_nop, 352 353 .mmu.lazy_mode = { 354 .enter = paravirt_nop, 355 .leave = paravirt_nop, 356 .flush = paravirt_nop, 357 }, 358 359 .mmu.set_fixmap = native_set_fixmap, 360 #endif /* CONFIG_PARAVIRT_XXL */ 361 362 #if defined(CONFIG_PARAVIRT_SPINLOCKS) 363 /* Lock ops. */ 364 #ifdef CONFIG_SMP 365 .lock.queued_spin_lock_slowpath = native_queued_spin_lock_slowpath, 366 .lock.queued_spin_unlock = 367 PV_CALLEE_SAVE(__native_queued_spin_unlock), 368 .lock.wait = paravirt_nop, 369 .lock.kick = paravirt_nop, 370 .lock.vcpu_is_preempted = 371 PV_CALLEE_SAVE(__native_vcpu_is_preempted), 372 #endif /* SMP */ 373 #endif 374 }; 375 376 #ifdef CONFIG_PARAVIRT_XXL 377 NOKPROBE_SYMBOL(native_load_idt); 378 #endif 379 380 EXPORT_SYMBOL(pv_ops); 381 EXPORT_SYMBOL_GPL(pv_info); 382