1 /* Paravirtualization interfaces
2 Copyright (C) 2006 Rusty Russell IBM Corporation
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 2007 - x86_64 support added by Glauber de Oliveira Costa, Red Hat Inc
21 #include <linux/errno.h>
22 #include <linux/init.h>
23 #include <linux/export.h>
24 #include <linux/efi.h>
25 #include <linux/bcd.h>
26 #include <linux/highmem.h>
27 #include <linux/kprobes.h>
30 #include <asm/paravirt.h>
31 #include <asm/debugreg.h>
33 #include <asm/setup.h>
34 #include <asm/pgtable.h>
36 #include <asm/pgalloc.h>
38 #include <asm/delay.h>
39 #include <asm/fixmap.h>
41 #include <asm/tlbflush.h>
42 #include <asm/timer.h>
43 #include <asm/special_insns.h>
47 * nop stub, which must not clobber anything *including the stack* to
48 * avoid confusing the entry prologues.
50 extern void _paravirt_nop(void);
51 asm (".pushsection .entry.text, \"ax\"\n"
52 ".global _paravirt_nop\n"
55 ".size _paravirt_nop, . - _paravirt_nop\n\t"
56 ".type _paravirt_nop, @function\n\t"
59 void __init default_banner(void)
61 printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
65 /* Undefined instruction for dealing with missing ops pointers. */
66 static const unsigned char ud2a[] = { 0x0f, 0x0b };
71 } __attribute__((packed));
73 static unsigned paravirt_patch_call(void *insnbuf, const void *target,
74 unsigned long addr, unsigned len)
76 struct branch *b = insnbuf;
77 unsigned long delta = (unsigned long)target - (addr+5);
80 #ifdef CONFIG_RETPOLINE
81 WARN_ONCE(1, "Failing to patch indirect CALL in %ps\n", (void *)addr);
83 return len; /* call too long for patch site */
86 b->opcode = 0xe8; /* call */
88 BUILD_BUG_ON(sizeof(*b) != 5);
93 #ifdef CONFIG_PARAVIRT_XXL
94 /* identity function, which can be inlined */
95 u64 notrace _paravirt_ident_64(u64 x)
100 static unsigned paravirt_patch_jmp(void *insnbuf, const void *target,
101 unsigned long addr, unsigned len)
103 struct branch *b = insnbuf;
104 unsigned long delta = (unsigned long)target - (addr+5);
107 #ifdef CONFIG_RETPOLINE
108 WARN_ONCE(1, "Failing to patch indirect JMP in %ps\n", (void *)addr);
110 return len; /* call too long for patch site */
113 b->opcode = 0xe9; /* jmp */
120 DEFINE_STATIC_KEY_TRUE(virt_spin_lock_key);
122 void __init native_pv_lock_init(void)
124 if (!static_cpu_has(X86_FEATURE_HYPERVISOR))
125 static_branch_disable(&virt_spin_lock_key);
128 unsigned paravirt_patch_default(u8 type, void *insnbuf,
129 unsigned long addr, unsigned len)
132 * Neat trick to map patch type back to the call within the
133 * corresponding structure.
135 void *opfunc = *((void **)&pv_ops + type);
139 /* If there's no function, patch it with a ud2a (BUG) */
140 ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a));
141 else if (opfunc == _paravirt_nop)
144 #ifdef CONFIG_PARAVIRT_XXL
145 /* identity functions just return their single argument */
146 else if (opfunc == _paravirt_ident_64)
147 ret = paravirt_patch_ident_64(insnbuf, len);
149 else if (type == PARAVIRT_PATCH(cpu.iret) ||
150 type == PARAVIRT_PATCH(cpu.usergs_sysret64))
151 /* If operation requires a jmp, then jmp */
152 ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len);
155 /* Otherwise call the function. */
156 ret = paravirt_patch_call(insnbuf, opfunc, addr, len);
161 unsigned paravirt_patch_insns(void *insnbuf, unsigned len,
162 const char *start, const char *end)
164 unsigned insn_len = end - start;
166 if (insn_len > len || start == NULL)
169 memcpy(insnbuf, start, insn_len);
174 static void native_flush_tlb(void)
176 __native_flush_tlb();
180 * Global pages have to be flushed a bit differently. Not a real
181 * performance problem because this does not happen often.
183 static void native_flush_tlb_global(void)
185 __native_flush_tlb_global();
188 static void native_flush_tlb_one_user(unsigned long addr)
190 __native_flush_tlb_one_user(addr);
193 struct static_key paravirt_steal_enabled;
194 struct static_key paravirt_steal_rq_enabled;
196 static u64 native_steal_clock(int cpu)
201 /* These are in entry.S */
202 extern void native_iret(void);
203 extern void native_usergs_sysret64(void);
205 static struct resource reserve_ioports = {
207 .end = IO_SPACE_LIMIT,
208 .name = "paravirt-ioport",
209 .flags = IORESOURCE_IO | IORESOURCE_BUSY,
213 * Reserve the whole legacy IO space to prevent any legacy drivers
214 * from wasting time probing for their hardware. This is a fairly
215 * brute-force approach to disabling all non-virtual drivers.
217 * Note that this must be called very early to have any effect.
219 int paravirt_disable_iospace(void)
221 return request_resource(&ioport_resource, &reserve_ioports);
224 static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE;
226 static inline void enter_lazy(enum paravirt_lazy_mode mode)
228 BUG_ON(this_cpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE);
230 this_cpu_write(paravirt_lazy_mode, mode);
233 static void leave_lazy(enum paravirt_lazy_mode mode)
235 BUG_ON(this_cpu_read(paravirt_lazy_mode) != mode);
237 this_cpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE);
240 void paravirt_enter_lazy_mmu(void)
242 enter_lazy(PARAVIRT_LAZY_MMU);
245 void paravirt_leave_lazy_mmu(void)
247 leave_lazy(PARAVIRT_LAZY_MMU);
250 void paravirt_flush_lazy_mmu(void)
254 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
255 arch_leave_lazy_mmu_mode();
256 arch_enter_lazy_mmu_mode();
262 #ifdef CONFIG_PARAVIRT_XXL
263 void paravirt_start_context_switch(struct task_struct *prev)
265 BUG_ON(preemptible());
267 if (this_cpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) {
268 arch_leave_lazy_mmu_mode();
269 set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES);
271 enter_lazy(PARAVIRT_LAZY_CPU);
274 void paravirt_end_context_switch(struct task_struct *next)
276 BUG_ON(preemptible());
278 leave_lazy(PARAVIRT_LAZY_CPU);
280 if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES))
281 arch_enter_lazy_mmu_mode();
285 enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
288 return PARAVIRT_LAZY_NONE;
290 return this_cpu_read(paravirt_lazy_mode);
293 struct pv_info pv_info = {
294 .name = "bare hardware",
295 #ifdef CONFIG_PARAVIRT_XXL
297 .shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */
300 .extra_user_64bit_cs = __USER_CS,
305 /* 64-bit pagetable entries */
306 #define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_64)
308 struct paravirt_patch_template pv_ops = {
310 .init.patch = native_patch,
313 .time.sched_clock = native_sched_clock,
314 .time.steal_clock = native_steal_clock,
317 .cpu.io_delay = native_io_delay,
319 #ifdef CONFIG_PARAVIRT_XXL
320 .cpu.cpuid = native_cpuid,
321 .cpu.get_debugreg = native_get_debugreg,
322 .cpu.set_debugreg = native_set_debugreg,
323 .cpu.read_cr0 = native_read_cr0,
324 .cpu.write_cr0 = native_write_cr0,
325 .cpu.write_cr4 = native_write_cr4,
327 .cpu.read_cr8 = native_read_cr8,
328 .cpu.write_cr8 = native_write_cr8,
330 .cpu.wbinvd = native_wbinvd,
331 .cpu.read_msr = native_read_msr,
332 .cpu.write_msr = native_write_msr,
333 .cpu.read_msr_safe = native_read_msr_safe,
334 .cpu.write_msr_safe = native_write_msr_safe,
335 .cpu.read_pmc = native_read_pmc,
336 .cpu.load_tr_desc = native_load_tr_desc,
337 .cpu.set_ldt = native_set_ldt,
338 .cpu.load_gdt = native_load_gdt,
339 .cpu.load_idt = native_load_idt,
340 .cpu.store_tr = native_store_tr,
341 .cpu.load_tls = native_load_tls,
343 .cpu.load_gs_index = native_load_gs_index,
345 .cpu.write_ldt_entry = native_write_ldt_entry,
346 .cpu.write_gdt_entry = native_write_gdt_entry,
347 .cpu.write_idt_entry = native_write_idt_entry,
349 .cpu.alloc_ldt = paravirt_nop,
350 .cpu.free_ldt = paravirt_nop,
352 .cpu.load_sp0 = native_load_sp0,
355 .cpu.usergs_sysret64 = native_usergs_sysret64,
357 .cpu.iret = native_iret,
358 .cpu.swapgs = native_swapgs,
360 .cpu.set_iopl_mask = native_set_iopl_mask,
362 .cpu.start_context_switch = paravirt_nop,
363 .cpu.end_context_switch = paravirt_nop,
366 .irq.save_fl = __PV_IS_CALLEE_SAVE(native_save_fl),
367 .irq.restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl),
368 .irq.irq_disable = __PV_IS_CALLEE_SAVE(native_irq_disable),
369 .irq.irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable),
370 .irq.safe_halt = native_safe_halt,
371 .irq.halt = native_halt,
372 #endif /* CONFIG_PARAVIRT_XXL */
375 .mmu.flush_tlb_user = native_flush_tlb,
376 .mmu.flush_tlb_kernel = native_flush_tlb_global,
377 .mmu.flush_tlb_one_user = native_flush_tlb_one_user,
378 .mmu.flush_tlb_others = native_flush_tlb_others,
379 .mmu.tlb_remove_table =
380 (void (*)(struct mmu_gather *, void *))tlb_remove_page,
382 .mmu.exit_mmap = paravirt_nop,
384 #ifdef CONFIG_PARAVIRT_XXL
385 .mmu.read_cr2 = native_read_cr2,
386 .mmu.write_cr2 = native_write_cr2,
387 .mmu.read_cr3 = __native_read_cr3,
388 .mmu.write_cr3 = native_write_cr3,
390 .mmu.pgd_alloc = __paravirt_pgd_alloc,
391 .mmu.pgd_free = paravirt_nop,
393 .mmu.alloc_pte = paravirt_nop,
394 .mmu.alloc_pmd = paravirt_nop,
395 .mmu.alloc_pud = paravirt_nop,
396 .mmu.alloc_p4d = paravirt_nop,
397 .mmu.release_pte = paravirt_nop,
398 .mmu.release_pmd = paravirt_nop,
399 .mmu.release_pud = paravirt_nop,
400 .mmu.release_p4d = paravirt_nop,
402 .mmu.set_pte = native_set_pte,
403 .mmu.set_pte_at = native_set_pte_at,
404 .mmu.set_pmd = native_set_pmd,
406 .mmu.ptep_modify_prot_start = __ptep_modify_prot_start,
407 .mmu.ptep_modify_prot_commit = __ptep_modify_prot_commit,
409 #if CONFIG_PGTABLE_LEVELS >= 3
410 #ifdef CONFIG_X86_PAE
411 .mmu.set_pte_atomic = native_set_pte_atomic,
412 .mmu.pte_clear = native_pte_clear,
413 .mmu.pmd_clear = native_pmd_clear,
415 .mmu.set_pud = native_set_pud,
417 .mmu.pmd_val = PTE_IDENT,
418 .mmu.make_pmd = PTE_IDENT,
420 #if CONFIG_PGTABLE_LEVELS >= 4
421 .mmu.pud_val = PTE_IDENT,
422 .mmu.make_pud = PTE_IDENT,
424 .mmu.set_p4d = native_set_p4d,
426 #if CONFIG_PGTABLE_LEVELS >= 5
427 .mmu.p4d_val = PTE_IDENT,
428 .mmu.make_p4d = PTE_IDENT,
430 .mmu.set_pgd = native_set_pgd,
431 #endif /* CONFIG_PGTABLE_LEVELS >= 5 */
432 #endif /* CONFIG_PGTABLE_LEVELS >= 4 */
433 #endif /* CONFIG_PGTABLE_LEVELS >= 3 */
435 .mmu.pte_val = PTE_IDENT,
436 .mmu.pgd_val = PTE_IDENT,
438 .mmu.make_pte = PTE_IDENT,
439 .mmu.make_pgd = PTE_IDENT,
441 .mmu.dup_mmap = paravirt_nop,
442 .mmu.activate_mm = paravirt_nop,
445 .enter = paravirt_nop,
446 .leave = paravirt_nop,
447 .flush = paravirt_nop,
450 .mmu.set_fixmap = native_set_fixmap,
451 #endif /* CONFIG_PARAVIRT_XXL */
453 #if defined(CONFIG_PARAVIRT_SPINLOCKS)
456 .lock.queued_spin_lock_slowpath = native_queued_spin_lock_slowpath,
457 .lock.queued_spin_unlock =
458 PV_CALLEE_SAVE(__native_queued_spin_unlock),
459 .lock.wait = paravirt_nop,
460 .lock.kick = paravirt_nop,
461 .lock.vcpu_is_preempted =
462 PV_CALLEE_SAVE(__native_vcpu_is_preempted),
467 #ifdef CONFIG_PARAVIRT_XXL
468 /* At this point, native_get/set_debugreg has real function entries */
469 NOKPROBE_SYMBOL(native_get_debugreg);
470 NOKPROBE_SYMBOL(native_set_debugreg);
471 NOKPROBE_SYMBOL(native_load_idt);
474 EXPORT_SYMBOL(pv_ops);
475 EXPORT_SYMBOL_GPL(pv_info);