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
default_banner(void)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. */
paravirt_BUG(void)53 noinstr void paravirt_BUG(void)
54 {
55 BUG();
56 }
57
paravirt_patch_call(void * insn_buff,const void * target,unsigned long addr,unsigned len)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
native_pv_lock_init(void)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
native_tlb_remove_table(struct mmu_gather * tlb,void * table)83 static void native_tlb_remove_table(struct mmu_gather *tlb, void *table)
84 {
85 tlb_remove_page(tlb, table);
86 }
87
paravirt_patch(u8 type,void * insn_buff,unsigned long addr,unsigned int len)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
native_steal_clock(int cpu)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
paravirt_set_sched_clock(u64 (* func)(void))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 */
paravirt_disable_iospace(void)141 int paravirt_disable_iospace(void)
142 {
143 return request_resource(&ioport_resource, &reserve_ioports);
144 }
145
146 #ifdef CONFIG_PARAVIRT_XXL
pv_native_write_cr2(unsigned long val)147 static noinstr void pv_native_write_cr2(unsigned long val)
148 {
149 native_write_cr2(val);
150 }
151
pv_native_get_debugreg(int regno)152 static noinstr unsigned long pv_native_get_debugreg(int regno)
153 {
154 return native_get_debugreg(regno);
155 }
156
pv_native_set_debugreg(int regno,unsigned long val)157 static noinstr void pv_native_set_debugreg(int regno, unsigned long val)
158 {
159 native_set_debugreg(regno, val);
160 }
161
pv_native_wbinvd(void)162 noinstr void pv_native_wbinvd(void)
163 {
164 native_wbinvd();
165 }
166
pv_native_safe_halt(void)167 static noinstr void pv_native_safe_halt(void)
168 {
169 native_safe_halt();
170 }
171 #endif
172
173 struct pv_info pv_info = {
174 .name = "bare hardware",
175 #ifdef CONFIG_PARAVIRT_XXL
176 .extra_user_64bit_cs = __USER_CS,
177 #endif
178 };
179
180 /* 64-bit pagetable entries */
181 #define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_64)
182
183 struct paravirt_patch_template pv_ops = {
184 /* Cpu ops. */
185 .cpu.io_delay = native_io_delay,
186
187 #ifdef CONFIG_PARAVIRT_XXL
188 .cpu.cpuid = native_cpuid,
189 .cpu.get_debugreg = pv_native_get_debugreg,
190 .cpu.set_debugreg = pv_native_set_debugreg,
191 .cpu.read_cr0 = native_read_cr0,
192 .cpu.write_cr0 = native_write_cr0,
193 .cpu.write_cr4 = native_write_cr4,
194 .cpu.wbinvd = pv_native_wbinvd,
195 .cpu.read_msr = native_read_msr,
196 .cpu.write_msr = native_write_msr,
197 .cpu.read_msr_safe = native_read_msr_safe,
198 .cpu.write_msr_safe = native_write_msr_safe,
199 .cpu.read_pmc = native_read_pmc,
200 .cpu.load_tr_desc = native_load_tr_desc,
201 .cpu.set_ldt = native_set_ldt,
202 .cpu.load_gdt = native_load_gdt,
203 .cpu.load_idt = native_load_idt,
204 .cpu.store_tr = native_store_tr,
205 .cpu.load_tls = native_load_tls,
206 .cpu.load_gs_index = native_load_gs_index,
207 .cpu.write_ldt_entry = native_write_ldt_entry,
208 .cpu.write_gdt_entry = native_write_gdt_entry,
209 .cpu.write_idt_entry = native_write_idt_entry,
210
211 .cpu.alloc_ldt = paravirt_nop,
212 .cpu.free_ldt = paravirt_nop,
213
214 .cpu.load_sp0 = native_load_sp0,
215
216 #ifdef CONFIG_X86_IOPL_IOPERM
217 .cpu.invalidate_io_bitmap = native_tss_invalidate_io_bitmap,
218 .cpu.update_io_bitmap = native_tss_update_io_bitmap,
219 #endif
220
221 .cpu.start_context_switch = paravirt_nop,
222 .cpu.end_context_switch = paravirt_nop,
223
224 /* Irq ops. */
225 .irq.save_fl = __PV_IS_CALLEE_SAVE(pv_native_save_fl),
226 .irq.irq_disable = __PV_IS_CALLEE_SAVE(pv_native_irq_disable),
227 .irq.irq_enable = __PV_IS_CALLEE_SAVE(pv_native_irq_enable),
228 .irq.safe_halt = pv_native_safe_halt,
229 .irq.halt = native_halt,
230 #endif /* CONFIG_PARAVIRT_XXL */
231
232 /* Mmu ops. */
233 .mmu.flush_tlb_user = native_flush_tlb_local,
234 .mmu.flush_tlb_kernel = native_flush_tlb_global,
235 .mmu.flush_tlb_one_user = native_flush_tlb_one_user,
236 .mmu.flush_tlb_multi = native_flush_tlb_multi,
237 .mmu.tlb_remove_table = native_tlb_remove_table,
238
239 .mmu.exit_mmap = paravirt_nop,
240 .mmu.notify_page_enc_status_changed = paravirt_nop,
241
242 #ifdef CONFIG_PARAVIRT_XXL
243 .mmu.read_cr2 = __PV_IS_CALLEE_SAVE(pv_native_read_cr2),
244 .mmu.write_cr2 = pv_native_write_cr2,
245 .mmu.read_cr3 = __native_read_cr3,
246 .mmu.write_cr3 = native_write_cr3,
247
248 .mmu.pgd_alloc = __paravirt_pgd_alloc,
249 .mmu.pgd_free = paravirt_nop,
250
251 .mmu.alloc_pte = paravirt_nop,
252 .mmu.alloc_pmd = paravirt_nop,
253 .mmu.alloc_pud = paravirt_nop,
254 .mmu.alloc_p4d = paravirt_nop,
255 .mmu.release_pte = paravirt_nop,
256 .mmu.release_pmd = paravirt_nop,
257 .mmu.release_pud = paravirt_nop,
258 .mmu.release_p4d = paravirt_nop,
259
260 .mmu.set_pte = native_set_pte,
261 .mmu.set_pmd = native_set_pmd,
262
263 .mmu.ptep_modify_prot_start = __ptep_modify_prot_start,
264 .mmu.ptep_modify_prot_commit = __ptep_modify_prot_commit,
265
266 .mmu.set_pud = native_set_pud,
267
268 .mmu.pmd_val = PTE_IDENT,
269 .mmu.make_pmd = PTE_IDENT,
270
271 .mmu.pud_val = PTE_IDENT,
272 .mmu.make_pud = PTE_IDENT,
273
274 .mmu.set_p4d = native_set_p4d,
275
276 #if CONFIG_PGTABLE_LEVELS >= 5
277 .mmu.p4d_val = PTE_IDENT,
278 .mmu.make_p4d = PTE_IDENT,
279
280 .mmu.set_pgd = native_set_pgd,
281 #endif /* CONFIG_PGTABLE_LEVELS >= 5 */
282
283 .mmu.pte_val = PTE_IDENT,
284 .mmu.pgd_val = PTE_IDENT,
285
286 .mmu.make_pte = PTE_IDENT,
287 .mmu.make_pgd = PTE_IDENT,
288
289 .mmu.enter_mmap = paravirt_nop,
290
291 .mmu.lazy_mode = {
292 .enter = paravirt_nop,
293 .leave = paravirt_nop,
294 .flush = paravirt_nop,
295 },
296
297 .mmu.set_fixmap = native_set_fixmap,
298 #endif /* CONFIG_PARAVIRT_XXL */
299
300 #if defined(CONFIG_PARAVIRT_SPINLOCKS)
301 /* Lock ops. */
302 #ifdef CONFIG_SMP
303 .lock.queued_spin_lock_slowpath = native_queued_spin_lock_slowpath,
304 .lock.queued_spin_unlock =
305 PV_CALLEE_SAVE(__native_queued_spin_unlock),
306 .lock.wait = paravirt_nop,
307 .lock.kick = paravirt_nop,
308 .lock.vcpu_is_preempted =
309 PV_CALLEE_SAVE(__native_vcpu_is_preempted),
310 #endif /* SMP */
311 #endif
312 };
313
314 #ifdef CONFIG_PARAVIRT_XXL
315 NOKPROBE_SYMBOL(native_load_idt);
316 #endif
317
318 EXPORT_SYMBOL(pv_ops);
319 EXPORT_SYMBOL_GPL(pv_info);
320
