2 * Copyright (C) 2010 SUSE Linux Products GmbH. All rights reserved.
5 * Alexander Graf <agraf@suse.de>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License, version 2, as
9 * published by the Free Software Foundation.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
21 #include <linux/kvm_host.h>
22 #include <linux/init.h>
23 #include <linux/kvm_para.h>
24 #include <linux/slab.h>
28 #include <asm/sections.h>
29 #include <asm/cacheflush.h>
30 #include <asm/disassemble.h>
32 #define KVM_MAGIC_PAGE (-4096L)
33 #define magic_var(x) KVM_MAGIC_PAGE + offsetof(struct kvm_vcpu_arch_shared, x)
35 #define KVM_INST_LWZ 0x80000000
36 #define KVM_INST_STW 0x90000000
37 #define KVM_INST_LD 0xe8000000
38 #define KVM_INST_STD 0xf8000000
39 #define KVM_INST_NOP 0x60000000
40 #define KVM_INST_B 0x48000000
41 #define KVM_INST_B_MASK 0x03ffffff
42 #define KVM_INST_B_MAX 0x01ffffff
44 #define KVM_MASK_RT 0x03e00000
45 #define KVM_INST_MFMSR 0x7c0000a6
46 #define KVM_INST_MFSPR_SPRG0 0x7c1042a6
47 #define KVM_INST_MFSPR_SPRG1 0x7c1142a6
48 #define KVM_INST_MFSPR_SPRG2 0x7c1242a6
49 #define KVM_INST_MFSPR_SPRG3 0x7c1342a6
50 #define KVM_INST_MFSPR_SRR0 0x7c1a02a6
51 #define KVM_INST_MFSPR_SRR1 0x7c1b02a6
52 #define KVM_INST_MFSPR_DAR 0x7c1302a6
53 #define KVM_INST_MFSPR_DSISR 0x7c1202a6
55 #define KVM_INST_MTSPR_SPRG0 0x7c1043a6
56 #define KVM_INST_MTSPR_SPRG1 0x7c1143a6
57 #define KVM_INST_MTSPR_SPRG2 0x7c1243a6
58 #define KVM_INST_MTSPR_SPRG3 0x7c1343a6
59 #define KVM_INST_MTSPR_SRR0 0x7c1a03a6
60 #define KVM_INST_MTSPR_SRR1 0x7c1b03a6
61 #define KVM_INST_MTSPR_DAR 0x7c1303a6
62 #define KVM_INST_MTSPR_DSISR 0x7c1203a6
64 #define KVM_INST_TLBSYNC 0x7c00046c
65 #define KVM_INST_MTMSRD_L0 0x7c000164
66 #define KVM_INST_MTMSRD_L1 0x7c010164
67 #define KVM_INST_MTMSR 0x7c000124
69 #define KVM_INST_WRTEEI_0 0x7c000146
70 #define KVM_INST_WRTEEI_1 0x7c008146
72 static bool kvm_patching_worked = true;
73 static char kvm_tmp[1024 * 1024];
74 static int kvm_tmp_index;
76 static inline void kvm_patch_ins(u32 *inst, u32 new_inst)
79 flush_icache_range((ulong)inst, (ulong)inst + 4);
82 static void kvm_patch_ins_ld(u32 *inst, long addr, u32 rt)
85 kvm_patch_ins(inst, KVM_INST_LD | rt | (addr & 0x0000fffc));
87 kvm_patch_ins(inst, KVM_INST_LWZ | rt | ((addr + 4) & 0x0000fffc));
91 static void kvm_patch_ins_lwz(u32 *inst, long addr, u32 rt)
93 kvm_patch_ins(inst, KVM_INST_LWZ | rt | (addr & 0x0000ffff));
96 static void kvm_patch_ins_std(u32 *inst, long addr, u32 rt)
99 kvm_patch_ins(inst, KVM_INST_STD | rt | (addr & 0x0000fffc));
101 kvm_patch_ins(inst, KVM_INST_STW | rt | ((addr + 4) & 0x0000fffc));
105 static void kvm_patch_ins_stw(u32 *inst, long addr, u32 rt)
107 kvm_patch_ins(inst, KVM_INST_STW | rt | (addr & 0x0000fffc));
110 static void kvm_patch_ins_nop(u32 *inst)
112 kvm_patch_ins(inst, KVM_INST_NOP);
115 static void kvm_patch_ins_b(u32 *inst, int addr)
117 #ifdef CONFIG_RELOCATABLE
118 /* On relocatable kernels interrupts handlers and our code
119 can be in different regions, so we don't patch them */
121 extern u32 __end_interrupts;
122 if ((ulong)inst < (ulong)&__end_interrupts)
126 kvm_patch_ins(inst, KVM_INST_B | (addr & KVM_INST_B_MASK));
129 static u32 *kvm_alloc(int len)
133 if ((kvm_tmp_index + len) > ARRAY_SIZE(kvm_tmp)) {
134 printk(KERN_ERR "KVM: No more space (%d + %d)\n",
136 kvm_patching_worked = false;
140 p = (void*)&kvm_tmp[kvm_tmp_index];
141 kvm_tmp_index += len;
146 extern u32 kvm_emulate_mtmsrd_branch_offs;
147 extern u32 kvm_emulate_mtmsrd_reg_offs;
148 extern u32 kvm_emulate_mtmsrd_len;
149 extern u32 kvm_emulate_mtmsrd[];
151 static void kvm_patch_ins_mtmsrd(u32 *inst, u32 rt)
158 p = kvm_alloc(kvm_emulate_mtmsrd_len * 4);
162 /* Find out where we are and put everything there */
163 distance_start = (ulong)p - (ulong)inst;
164 next_inst = ((ulong)inst + 4);
165 distance_end = next_inst - (ulong)&p[kvm_emulate_mtmsrd_branch_offs];
167 /* Make sure we only write valid b instructions */
168 if (distance_start > KVM_INST_B_MAX) {
169 kvm_patching_worked = false;
173 /* Modify the chunk to fit the invocation */
174 memcpy(p, kvm_emulate_mtmsrd, kvm_emulate_mtmsrd_len * 4);
175 p[kvm_emulate_mtmsrd_branch_offs] |= distance_end & KVM_INST_B_MASK;
176 p[kvm_emulate_mtmsrd_reg_offs] |= rt;
177 flush_icache_range((ulong)p, (ulong)p + kvm_emulate_mtmsrd_len * 4);
179 /* Patch the invocation */
180 kvm_patch_ins_b(inst, distance_start);
183 extern u32 kvm_emulate_mtmsr_branch_offs;
184 extern u32 kvm_emulate_mtmsr_reg1_offs;
185 extern u32 kvm_emulate_mtmsr_reg2_offs;
186 extern u32 kvm_emulate_mtmsr_reg3_offs;
187 extern u32 kvm_emulate_mtmsr_orig_ins_offs;
188 extern u32 kvm_emulate_mtmsr_len;
189 extern u32 kvm_emulate_mtmsr[];
191 static void kvm_patch_ins_mtmsr(u32 *inst, u32 rt)
198 p = kvm_alloc(kvm_emulate_mtmsr_len * 4);
202 /* Find out where we are and put everything there */
203 distance_start = (ulong)p - (ulong)inst;
204 next_inst = ((ulong)inst + 4);
205 distance_end = next_inst - (ulong)&p[kvm_emulate_mtmsr_branch_offs];
207 /* Make sure we only write valid b instructions */
208 if (distance_start > KVM_INST_B_MAX) {
209 kvm_patching_worked = false;
213 /* Modify the chunk to fit the invocation */
214 memcpy(p, kvm_emulate_mtmsr, kvm_emulate_mtmsr_len * 4);
215 p[kvm_emulate_mtmsr_branch_offs] |= distance_end & KVM_INST_B_MASK;
216 p[kvm_emulate_mtmsr_reg1_offs] |= rt;
217 p[kvm_emulate_mtmsr_reg2_offs] |= rt;
218 p[kvm_emulate_mtmsr_reg3_offs] |= rt;
219 p[kvm_emulate_mtmsr_orig_ins_offs] = *inst;
220 flush_icache_range((ulong)p, (ulong)p + kvm_emulate_mtmsr_len * 4);
222 /* Patch the invocation */
223 kvm_patch_ins_b(inst, distance_start);
228 extern u32 kvm_emulate_wrteei_branch_offs;
229 extern u32 kvm_emulate_wrteei_ee_offs;
230 extern u32 kvm_emulate_wrteei_len;
231 extern u32 kvm_emulate_wrteei[];
233 static void kvm_patch_ins_wrteei(u32 *inst)
240 p = kvm_alloc(kvm_emulate_wrteei_len * 4);
244 /* Find out where we are and put everything there */
245 distance_start = (ulong)p - (ulong)inst;
246 next_inst = ((ulong)inst + 4);
247 distance_end = next_inst - (ulong)&p[kvm_emulate_wrteei_branch_offs];
249 /* Make sure we only write valid b instructions */
250 if (distance_start > KVM_INST_B_MAX) {
251 kvm_patching_worked = false;
255 /* Modify the chunk to fit the invocation */
256 memcpy(p, kvm_emulate_wrteei, kvm_emulate_wrteei_len * 4);
257 p[kvm_emulate_wrteei_branch_offs] |= distance_end & KVM_INST_B_MASK;
258 p[kvm_emulate_wrteei_ee_offs] |= (*inst & MSR_EE);
259 flush_icache_range((ulong)p, (ulong)p + kvm_emulate_wrteei_len * 4);
261 /* Patch the invocation */
262 kvm_patch_ins_b(inst, distance_start);
267 static void kvm_map_magic_page(void *data)
269 u32 *features = data;
274 in[0] = KVM_MAGIC_PAGE;
275 in[1] = KVM_MAGIC_PAGE;
277 kvm_hypercall(in, out, HC_VENDOR_KVM | KVM_HC_PPC_MAP_MAGIC_PAGE);
282 static void kvm_check_ins(u32 *inst, u32 features)
285 u32 inst_no_rt = _inst & ~KVM_MASK_RT;
286 u32 inst_rt = _inst & KVM_MASK_RT;
288 switch (inst_no_rt) {
291 kvm_patch_ins_ld(inst, magic_var(msr), inst_rt);
293 case KVM_INST_MFSPR_SPRG0:
294 kvm_patch_ins_ld(inst, magic_var(sprg0), inst_rt);
296 case KVM_INST_MFSPR_SPRG1:
297 kvm_patch_ins_ld(inst, magic_var(sprg1), inst_rt);
299 case KVM_INST_MFSPR_SPRG2:
300 kvm_patch_ins_ld(inst, magic_var(sprg2), inst_rt);
302 case KVM_INST_MFSPR_SPRG3:
303 kvm_patch_ins_ld(inst, magic_var(sprg3), inst_rt);
305 case KVM_INST_MFSPR_SRR0:
306 kvm_patch_ins_ld(inst, magic_var(srr0), inst_rt);
308 case KVM_INST_MFSPR_SRR1:
309 kvm_patch_ins_ld(inst, magic_var(srr1), inst_rt);
311 case KVM_INST_MFSPR_DAR:
312 kvm_patch_ins_ld(inst, magic_var(dar), inst_rt);
314 case KVM_INST_MFSPR_DSISR:
315 kvm_patch_ins_lwz(inst, magic_var(dsisr), inst_rt);
319 case KVM_INST_MTSPR_SPRG0:
320 kvm_patch_ins_std(inst, magic_var(sprg0), inst_rt);
322 case KVM_INST_MTSPR_SPRG1:
323 kvm_patch_ins_std(inst, magic_var(sprg1), inst_rt);
325 case KVM_INST_MTSPR_SPRG2:
326 kvm_patch_ins_std(inst, magic_var(sprg2), inst_rt);
328 case KVM_INST_MTSPR_SPRG3:
329 kvm_patch_ins_std(inst, magic_var(sprg3), inst_rt);
331 case KVM_INST_MTSPR_SRR0:
332 kvm_patch_ins_std(inst, magic_var(srr0), inst_rt);
334 case KVM_INST_MTSPR_SRR1:
335 kvm_patch_ins_std(inst, magic_var(srr1), inst_rt);
337 case KVM_INST_MTSPR_DAR:
338 kvm_patch_ins_std(inst, magic_var(dar), inst_rt);
340 case KVM_INST_MTSPR_DSISR:
341 kvm_patch_ins_stw(inst, magic_var(dsisr), inst_rt);
345 case KVM_INST_TLBSYNC:
346 kvm_patch_ins_nop(inst);
350 case KVM_INST_MTMSRD_L1:
351 /* We use r30 and r31 during the hook */
352 if (get_rt(inst_rt) < 30)
353 kvm_patch_ins_mtmsrd(inst, inst_rt);
356 case KVM_INST_MTMSRD_L0:
357 /* We use r30 and r31 during the hook */
358 if (get_rt(inst_rt) < 30)
359 kvm_patch_ins_mtmsr(inst, inst_rt);
365 case KVM_INST_WRTEEI_0:
366 case KVM_INST_WRTEEI_1:
367 kvm_patch_ins_wrteei(inst);
373 static void kvm_use_magic_page(void)
380 /* Tell the host to map the magic page to -4096 on all CPUs */
381 on_each_cpu(kvm_map_magic_page, &features, 1);
383 /* Quick self-test to see if the mapping works */
384 if (__get_user(tmp, (u32*)KVM_MAGIC_PAGE)) {
385 kvm_patching_worked = false;
389 /* Now loop through all code and find instructions */
390 start = (void*)_stext;
393 for (p = start; p < end; p++)
394 kvm_check_ins(p, features);
396 printk(KERN_INFO "KVM: Live patching for a fast VM %s\n",
397 kvm_patching_worked ? "worked" : "failed");
400 unsigned long kvm_hypercall(unsigned long *in,
404 unsigned long register r0 asm("r0");
405 unsigned long register r3 asm("r3") = in[0];
406 unsigned long register r4 asm("r4") = in[1];
407 unsigned long register r5 asm("r5") = in[2];
408 unsigned long register r6 asm("r6") = in[3];
409 unsigned long register r7 asm("r7") = in[4];
410 unsigned long register r8 asm("r8") = in[5];
411 unsigned long register r9 asm("r9") = in[6];
412 unsigned long register r10 asm("r10") = in[7];
413 unsigned long register r11 asm("r11") = nr;
414 unsigned long register r12 asm("r12");
416 asm volatile("bl kvm_hypercall_start"
417 : "=r"(r0), "=r"(r3), "=r"(r4), "=r"(r5), "=r"(r6),
418 "=r"(r7), "=r"(r8), "=r"(r9), "=r"(r10), "=r"(r11),
420 : "r"(r3), "r"(r4), "r"(r5), "r"(r6), "r"(r7), "r"(r8),
421 "r"(r9), "r"(r10), "r"(r11)
422 : "memory", "cc", "xer", "ctr", "lr");
435 EXPORT_SYMBOL_GPL(kvm_hypercall);
437 static int kvm_para_setup(void)
439 extern u32 kvm_hypercall_start;
440 struct device_node *hyper_node;
444 hyper_node = of_find_node_by_path("/hypervisor");
448 insts = (u32*)of_get_property(hyper_node, "hcall-instructions", &len);
454 for (i = 0; i < (len / 4); i++)
455 kvm_patch_ins(&(&kvm_hypercall_start)[i], insts[i]);
460 static __init void kvm_free_tmp(void)
462 unsigned long start, end;
464 start = (ulong)&kvm_tmp[kvm_tmp_index + (PAGE_SIZE - 1)] & PAGE_MASK;
465 end = (ulong)&kvm_tmp[ARRAY_SIZE(kvm_tmp)] & PAGE_MASK;
467 /* Free the tmp space we don't need */
468 for (; start < end; start += PAGE_SIZE) {
469 ClearPageReserved(virt_to_page(start));
470 init_page_count(virt_to_page(start));
476 static int __init kvm_guest_init(void)
478 if (!kvm_para_available())
481 if (kvm_para_setup())
484 if (kvm_para_has_feature(KVM_FEATURE_MAGIC_PAGE))
485 kvm_use_magic_page();
493 postcore_initcall(kvm_guest_init);