1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2013 Anish Gupta (akgupt3@gmail.com)
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice unmodified, this list of conditions, and the following
12 * disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 #include "opt_bhyve_snapshot.h"
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34
35 #include <machine/segments.h>
36 #include <machine/specialreg.h>
37 #include <machine/vmm.h>
38 #include <machine/vmm_snapshot.h>
39
40 #include "vmm_ktr.h"
41
42 #include "vmcb.h"
43 #include "svm.h"
44 #include "svm_softc.h"
45
46 /*
47 * The VMCB aka Virtual Machine Control Block is a 4KB aligned page
48 * in memory that describes the virtual machine.
49 *
50 * The VMCB contains:
51 * - instructions or events in the guest to intercept
52 * - control bits that modify execution environment of the guest
53 * - guest processor state (e.g. general purpose registers)
54 */
55
56 /*
57 * Return VMCB segment area.
58 */
59 static struct vmcb_segment *
vmcb_segptr(struct vmcb * vmcb,int type)60 vmcb_segptr(struct vmcb *vmcb, int type)
61 {
62 struct vmcb_state *state;
63 struct vmcb_segment *seg;
64
65 state = &vmcb->state;
66
67 switch (type) {
68 case VM_REG_GUEST_CS:
69 seg = &state->cs;
70 break;
71
72 case VM_REG_GUEST_DS:
73 seg = &state->ds;
74 break;
75
76 case VM_REG_GUEST_ES:
77 seg = &state->es;
78 break;
79
80 case VM_REG_GUEST_FS:
81 seg = &state->fs;
82 break;
83
84 case VM_REG_GUEST_GS:
85 seg = &state->gs;
86 break;
87
88 case VM_REG_GUEST_SS:
89 seg = &state->ss;
90 break;
91
92 case VM_REG_GUEST_GDTR:
93 seg = &state->gdt;
94 break;
95
96 case VM_REG_GUEST_IDTR:
97 seg = &state->idt;
98 break;
99
100 case VM_REG_GUEST_LDTR:
101 seg = &state->ldt;
102 break;
103
104 case VM_REG_GUEST_TR:
105 seg = &state->tr;
106 break;
107
108 default:
109 seg = NULL;
110 break;
111 }
112
113 return (seg);
114 }
115
116 static int
vmcb_access(struct svm_vcpu * vcpu,int write,int ident,uint64_t * val)117 vmcb_access(struct svm_vcpu *vcpu, int write, int ident, uint64_t *val)
118 {
119 struct vmcb *vmcb;
120 int off, bytes;
121 char *ptr;
122
123 vmcb = svm_get_vmcb(vcpu);
124 off = VMCB_ACCESS_OFFSET(ident);
125 bytes = VMCB_ACCESS_BYTES(ident);
126
127 if ((off + bytes) >= sizeof (struct vmcb))
128 return (EINVAL);
129
130 ptr = (char *)vmcb;
131
132 if (!write)
133 *val = 0;
134
135 switch (bytes) {
136 case 8:
137 case 4:
138 case 2:
139 case 1:
140 if (write)
141 memcpy(ptr + off, val, bytes);
142 else
143 memcpy(val, ptr + off, bytes);
144 break;
145 default:
146 SVM_CTR1(vcpu, "Invalid size %d for VMCB access: %d", bytes);
147 return (EINVAL);
148 }
149
150 /* Invalidate all VMCB state cached by h/w. */
151 if (write)
152 svm_set_dirty(vcpu, 0xffffffff);
153
154 return (0);
155 }
156
157 /*
158 * Read from segment selector, control and general purpose register of VMCB.
159 */
160 int
vmcb_read(struct svm_vcpu * vcpu,int ident,uint64_t * retval)161 vmcb_read(struct svm_vcpu *vcpu, int ident, uint64_t *retval)
162 {
163 struct vmcb *vmcb;
164 struct vmcb_state *state;
165 struct vmcb_segment *seg;
166 int err;
167
168 vmcb = svm_get_vmcb(vcpu);
169 state = &vmcb->state;
170 err = 0;
171
172 if (VMCB_ACCESS_OK(ident))
173 return (vmcb_access(vcpu, 0, ident, retval));
174
175 switch (ident) {
176 case VM_REG_GUEST_CR0:
177 *retval = state->cr0;
178 break;
179
180 case VM_REG_GUEST_CR2:
181 *retval = state->cr2;
182 break;
183
184 case VM_REG_GUEST_CR3:
185 *retval = state->cr3;
186 break;
187
188 case VM_REG_GUEST_CR4:
189 *retval = state->cr4;
190 break;
191
192 case VM_REG_GUEST_DR6:
193 *retval = state->dr6;
194 break;
195
196 case VM_REG_GUEST_DR7:
197 *retval = state->dr7;
198 break;
199
200 case VM_REG_GUEST_EFER:
201 *retval = state->efer;
202 break;
203
204 case VM_REG_GUEST_RAX:
205 *retval = state->rax;
206 break;
207
208 case VM_REG_GUEST_RFLAGS:
209 *retval = state->rflags;
210 break;
211
212 case VM_REG_GUEST_RIP:
213 *retval = state->rip;
214 break;
215
216 case VM_REG_GUEST_RSP:
217 *retval = state->rsp;
218 break;
219
220 case VM_REG_GUEST_CS:
221 case VM_REG_GUEST_DS:
222 case VM_REG_GUEST_ES:
223 case VM_REG_GUEST_FS:
224 case VM_REG_GUEST_GS:
225 case VM_REG_GUEST_SS:
226 case VM_REG_GUEST_LDTR:
227 case VM_REG_GUEST_TR:
228 seg = vmcb_segptr(vmcb, ident);
229 KASSERT(seg != NULL, ("%s: unable to get segment %d from VMCB",
230 __func__, ident));
231 *retval = seg->selector;
232 break;
233
234 case VM_REG_GUEST_GDTR:
235 case VM_REG_GUEST_IDTR:
236 /* GDTR and IDTR don't have segment selectors */
237 err = EINVAL;
238 break;
239 default:
240 err = EINVAL;
241 break;
242 }
243
244 return (err);
245 }
246
247 /*
248 * Write to segment selector, control and general purpose register of VMCB.
249 */
250 int
vmcb_write(struct svm_vcpu * vcpu,int ident,uint64_t val)251 vmcb_write(struct svm_vcpu *vcpu, int ident, uint64_t val)
252 {
253 struct vmcb *vmcb;
254 struct vmcb_state *state;
255 struct vmcb_segment *seg;
256 int err, dirtyseg;
257
258 vmcb = svm_get_vmcb(vcpu);
259 state = &vmcb->state;
260 dirtyseg = 0;
261 err = 0;
262
263 if (VMCB_ACCESS_OK(ident))
264 return (vmcb_access(vcpu, 1, ident, &val));
265
266 switch (ident) {
267 case VM_REG_GUEST_CR0:
268 state->cr0 = val;
269 svm_set_dirty(vcpu, VMCB_CACHE_CR);
270 break;
271
272 case VM_REG_GUEST_CR2:
273 state->cr2 = val;
274 svm_set_dirty(vcpu, VMCB_CACHE_CR2);
275 break;
276
277 case VM_REG_GUEST_CR3:
278 state->cr3 = val;
279 svm_set_dirty(vcpu, VMCB_CACHE_CR);
280 break;
281
282 case VM_REG_GUEST_CR4:
283 state->cr4 = val;
284 svm_set_dirty(vcpu, VMCB_CACHE_CR);
285 break;
286
287 case VM_REG_GUEST_DR6:
288 state->dr6 = val;
289 svm_set_dirty(vcpu, VMCB_CACHE_DR);
290 break;
291
292 case VM_REG_GUEST_DR7:
293 state->dr7 = val;
294 svm_set_dirty(vcpu, VMCB_CACHE_DR);
295 break;
296
297 case VM_REG_GUEST_EFER:
298 /* EFER_SVM must always be set when the guest is executing */
299 state->efer = val | EFER_SVM;
300 svm_set_dirty(vcpu, VMCB_CACHE_CR);
301 break;
302
303 case VM_REG_GUEST_RAX:
304 state->rax = val;
305 break;
306
307 case VM_REG_GUEST_RFLAGS:
308 state->rflags = val;
309 break;
310
311 case VM_REG_GUEST_RIP:
312 state->rip = val;
313 break;
314
315 case VM_REG_GUEST_RSP:
316 state->rsp = val;
317 break;
318
319 case VM_REG_GUEST_CS:
320 case VM_REG_GUEST_DS:
321 case VM_REG_GUEST_ES:
322 case VM_REG_GUEST_SS:
323 dirtyseg = 1; /* FALLTHROUGH */
324 case VM_REG_GUEST_FS:
325 case VM_REG_GUEST_GS:
326 case VM_REG_GUEST_LDTR:
327 case VM_REG_GUEST_TR:
328 seg = vmcb_segptr(vmcb, ident);
329 KASSERT(seg != NULL, ("%s: unable to get segment %d from VMCB",
330 __func__, ident));
331 seg->selector = val;
332 if (dirtyseg)
333 svm_set_dirty(vcpu, VMCB_CACHE_SEG);
334 break;
335
336 case VM_REG_GUEST_GDTR:
337 case VM_REG_GUEST_IDTR:
338 /* GDTR and IDTR don't have segment selectors */
339 err = EINVAL;
340 break;
341 default:
342 err = EINVAL;
343 break;
344 }
345
346 return (err);
347 }
348
349 int
vmcb_seg(struct vmcb * vmcb,int ident,struct vmcb_segment * seg2)350 vmcb_seg(struct vmcb *vmcb, int ident, struct vmcb_segment *seg2)
351 {
352 struct vmcb_segment *seg;
353
354 seg = vmcb_segptr(vmcb, ident);
355 if (seg != NULL) {
356 bcopy(seg, seg2, sizeof(struct vmcb_segment));
357 return (0);
358 } else {
359 return (EINVAL);
360 }
361 }
362
363 int
vmcb_setdesc(struct svm_vcpu * vcpu,int reg,struct seg_desc * desc)364 vmcb_setdesc(struct svm_vcpu *vcpu, int reg, struct seg_desc *desc)
365 {
366 struct vmcb *vmcb;
367 struct vmcb_segment *seg;
368 uint16_t attrib;
369
370 vmcb = svm_get_vmcb(vcpu);
371
372 seg = vmcb_segptr(vmcb, reg);
373 KASSERT(seg != NULL, ("%s: invalid segment descriptor %d",
374 __func__, reg));
375
376 seg->base = desc->base;
377 seg->limit = desc->limit;
378 if (reg != VM_REG_GUEST_GDTR && reg != VM_REG_GUEST_IDTR) {
379 /*
380 * Map seg_desc access to VMCB attribute format.
381 *
382 * SVM uses the 'P' bit in the segment attributes to indicate a
383 * NULL segment so clear it if the segment is marked unusable.
384 */
385 attrib = ((desc->access & 0xF000) >> 4) | (desc->access & 0xFF);
386 if (SEG_DESC_UNUSABLE(desc->access)) {
387 attrib &= ~0x80;
388 }
389 seg->attrib = attrib;
390 }
391
392 SVM_CTR4(vcpu, "Setting desc %d: base (%#lx), limit (%#x), "
393 "attrib (%#x)", reg, seg->base, seg->limit, seg->attrib);
394
395 switch (reg) {
396 case VM_REG_GUEST_CS:
397 case VM_REG_GUEST_DS:
398 case VM_REG_GUEST_ES:
399 case VM_REG_GUEST_SS:
400 svm_set_dirty(vcpu, VMCB_CACHE_SEG);
401 break;
402 case VM_REG_GUEST_GDTR:
403 case VM_REG_GUEST_IDTR:
404 svm_set_dirty(vcpu, VMCB_CACHE_DT);
405 break;
406 default:
407 break;
408 }
409
410 return (0);
411 }
412
413 int
vmcb_getdesc(struct svm_vcpu * vcpu,int reg,struct seg_desc * desc)414 vmcb_getdesc(struct svm_vcpu *vcpu, int reg, struct seg_desc *desc)
415 {
416 struct vmcb *vmcb;
417 struct vmcb_segment *seg;
418
419 vmcb = svm_get_vmcb(vcpu);
420 seg = vmcb_segptr(vmcb, reg);
421 KASSERT(seg != NULL, ("%s: invalid segment descriptor %d",
422 __func__, reg));
423
424 desc->base = seg->base;
425 desc->limit = seg->limit;
426 desc->access = 0;
427
428 if (reg != VM_REG_GUEST_GDTR && reg != VM_REG_GUEST_IDTR) {
429 /* Map seg_desc access to VMCB attribute format */
430 desc->access = ((seg->attrib & 0xF00) << 4) |
431 (seg->attrib & 0xFF);
432
433 /*
434 * VT-x uses bit 16 to indicate a segment that has been loaded
435 * with a NULL selector (aka unusable). The 'desc->access'
436 * field is interpreted in the VT-x format by the
437 * processor-independent code.
438 *
439 * SVM uses the 'P' bit to convey the same information so
440 * convert it into the VT-x format. For more details refer to
441 * section "Segment State in the VMCB" in APMv2.
442 */
443 if (reg != VM_REG_GUEST_CS && reg != VM_REG_GUEST_TR) {
444 if ((desc->access & 0x80) == 0)
445 desc->access |= 0x10000; /* Unusable segment */
446 }
447 }
448
449 return (0);
450 }
451
452 #ifdef BHYVE_SNAPSHOT
453 int
vmcb_getany(struct svm_vcpu * vcpu,int ident,uint64_t * val)454 vmcb_getany(struct svm_vcpu *vcpu, int ident, uint64_t *val)
455 {
456 int error = 0;
457
458 if (ident >= VM_REG_LAST) {
459 error = EINVAL;
460 goto err;
461 }
462
463 error = vmcb_read(vcpu, ident, val);
464
465 err:
466 return (error);
467 }
468
469 int
vmcb_setany(struct svm_vcpu * vcpu,int ident,uint64_t val)470 vmcb_setany(struct svm_vcpu *vcpu, int ident, uint64_t val)
471 {
472 int error = 0;
473
474 if (ident >= VM_REG_LAST) {
475 error = EINVAL;
476 goto err;
477 }
478
479 error = vmcb_write(vcpu, ident, val);
480
481 err:
482 return (error);
483 }
484
485 int
vmcb_snapshot_desc(struct svm_vcpu * vcpu,int reg,struct vm_snapshot_meta * meta)486 vmcb_snapshot_desc(struct svm_vcpu *vcpu, int reg,
487 struct vm_snapshot_meta *meta)
488 {
489 int ret;
490 struct seg_desc desc;
491
492 if (meta->op == VM_SNAPSHOT_SAVE) {
493 ret = vmcb_getdesc(vcpu, reg, &desc);
494 if (ret != 0)
495 goto done;
496
497 SNAPSHOT_VAR_OR_LEAVE(desc.base, meta, ret, done);
498 SNAPSHOT_VAR_OR_LEAVE(desc.limit, meta, ret, done);
499 SNAPSHOT_VAR_OR_LEAVE(desc.access, meta, ret, done);
500 } else if (meta->op == VM_SNAPSHOT_RESTORE) {
501 SNAPSHOT_VAR_OR_LEAVE(desc.base, meta, ret, done);
502 SNAPSHOT_VAR_OR_LEAVE(desc.limit, meta, ret, done);
503 SNAPSHOT_VAR_OR_LEAVE(desc.access, meta, ret, done);
504
505 ret = vmcb_setdesc(vcpu, reg, &desc);
506 if (ret != 0)
507 goto done;
508 } else {
509 ret = EINVAL;
510 goto done;
511 }
512
513 done:
514 return (ret);
515 }
516
517 int
vmcb_snapshot_any(struct svm_vcpu * vcpu,int ident,struct vm_snapshot_meta * meta)518 vmcb_snapshot_any(struct svm_vcpu *vcpu, int ident,
519 struct vm_snapshot_meta *meta)
520 {
521 int ret;
522 uint64_t val;
523
524 if (meta->op == VM_SNAPSHOT_SAVE) {
525 ret = vmcb_getany(vcpu, ident, &val);
526 if (ret != 0)
527 goto done;
528
529 SNAPSHOT_VAR_OR_LEAVE(val, meta, ret, done);
530 } else if (meta->op == VM_SNAPSHOT_RESTORE) {
531 SNAPSHOT_VAR_OR_LEAVE(val, meta, ret, done);
532
533 ret = vmcb_setany(vcpu, ident, val);
534 if (ret != 0)
535 goto done;
536 } else {
537 ret = EINVAL;
538 goto done;
539 }
540
541 done:
542 return (ret);
543 }
544 #endif
545