1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2013 Anish Gupta ([email protected])
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 __FBSDID("$FreeBSD$");
31
32 #include "opt_bhyve_snapshot.h"
33
34 #include <sys/param.h>
35 #include <sys/systm.h>
36
37 #include <machine/segments.h>
38 #include <machine/specialreg.h>
39 #include <machine/vmm.h>
40 #include <machine/vmm_snapshot.h>
41
42 #include "vmm_ktr.h"
43
44 #include "vmcb.h"
45 #include "svm.h"
46 #include "svm_softc.h"
47
48 /*
49 * The VMCB aka Virtual Machine Control Block is a 4KB aligned page
50 * in memory that describes the virtual machine.
51 *
52 * The VMCB contains:
53 * - instructions or events in the guest to intercept
54 * - control bits that modify execution environment of the guest
55 * - guest processor state (e.g. general purpose registers)
56 */
57
58 /*
59 * Return VMCB segment area.
60 */
61 static struct vmcb_segment *
vmcb_segptr(struct vmcb * vmcb,int type)62 vmcb_segptr(struct vmcb *vmcb, int type)
63 {
64 struct vmcb_state *state;
65 struct vmcb_segment *seg;
66
67 state = &vmcb->state;
68
69 switch (type) {
70 case VM_REG_GUEST_CS:
71 seg = &state->cs;
72 break;
73
74 case VM_REG_GUEST_DS:
75 seg = &state->ds;
76 break;
77
78 case VM_REG_GUEST_ES:
79 seg = &state->es;
80 break;
81
82 case VM_REG_GUEST_FS:
83 seg = &state->fs;
84 break;
85
86 case VM_REG_GUEST_GS:
87 seg = &state->gs;
88 break;
89
90 case VM_REG_GUEST_SS:
91 seg = &state->ss;
92 break;
93
94 case VM_REG_GUEST_GDTR:
95 seg = &state->gdt;
96 break;
97
98 case VM_REG_GUEST_IDTR:
99 seg = &state->idt;
100 break;
101
102 case VM_REG_GUEST_LDTR:
103 seg = &state->ldt;
104 break;
105
106 case VM_REG_GUEST_TR:
107 seg = &state->tr;
108 break;
109
110 default:
111 seg = NULL;
112 break;
113 }
114
115 return (seg);
116 }
117
118 static int
vmcb_access(struct svm_softc * softc,int vcpu,int write,int ident,uint64_t * val)119 vmcb_access(struct svm_softc *softc, int vcpu, int write, int ident,
120 uint64_t *val)
121 {
122 struct vmcb *vmcb;
123 int off, bytes;
124 char *ptr;
125
126 vmcb = svm_get_vmcb(softc, vcpu);
127 off = VMCB_ACCESS_OFFSET(ident);
128 bytes = VMCB_ACCESS_BYTES(ident);
129
130 if ((off + bytes) >= sizeof (struct vmcb))
131 return (EINVAL);
132
133 ptr = (char *)vmcb;
134
135 if (!write)
136 *val = 0;
137
138 switch (bytes) {
139 case 8:
140 case 4:
141 case 2:
142 if (write)
143 memcpy(ptr + off, val, bytes);
144 else
145 memcpy(val, ptr + off, bytes);
146 break;
147 default:
148 VCPU_CTR1(softc->vm, vcpu,
149 "Invalid size %d for VMCB access: %d", bytes);
150 return (EINVAL);
151 }
152
153 /* Invalidate all VMCB state cached by h/w. */
154 if (write)
155 svm_set_dirty(softc, vcpu, 0xffffffff);
156
157 return (0);
158 }
159
160 /*
161 * Read from segment selector, control and general purpose register of VMCB.
162 */
163 int
vmcb_read(struct svm_softc * sc,int vcpu,int ident,uint64_t * retval)164 vmcb_read(struct svm_softc *sc, int vcpu, int ident, uint64_t *retval)
165 {
166 struct vmcb *vmcb;
167 struct vmcb_state *state;
168 struct vmcb_segment *seg;
169 int err;
170
171 vmcb = svm_get_vmcb(sc, vcpu);
172 state = &vmcb->state;
173 err = 0;
174
175 if (VMCB_ACCESS_OK(ident))
176 return (vmcb_access(sc, vcpu, 0, ident, retval));
177
178 switch (ident) {
179 case VM_REG_GUEST_CR0:
180 *retval = state->cr0;
181 break;
182
183 case VM_REG_GUEST_CR2:
184 *retval = state->cr2;
185 break;
186
187 case VM_REG_GUEST_CR3:
188 *retval = state->cr3;
189 break;
190
191 case VM_REG_GUEST_CR4:
192 *retval = state->cr4;
193 break;
194
195 case VM_REG_GUEST_DR6:
196 *retval = state->dr6;
197 break;
198
199 case VM_REG_GUEST_DR7:
200 *retval = state->dr7;
201 break;
202
203 case VM_REG_GUEST_EFER:
204 *retval = state->efer;
205 break;
206
207 case VM_REG_GUEST_RAX:
208 *retval = state->rax;
209 break;
210
211 case VM_REG_GUEST_RFLAGS:
212 *retval = state->rflags;
213 break;
214
215 case VM_REG_GUEST_RIP:
216 *retval = state->rip;
217 break;
218
219 case VM_REG_GUEST_RSP:
220 *retval = state->rsp;
221 break;
222
223 case VM_REG_GUEST_CS:
224 case VM_REG_GUEST_DS:
225 case VM_REG_GUEST_ES:
226 case VM_REG_GUEST_FS:
227 case VM_REG_GUEST_GS:
228 case VM_REG_GUEST_SS:
229 case VM_REG_GUEST_LDTR:
230 case VM_REG_GUEST_TR:
231 seg = vmcb_segptr(vmcb, ident);
232 KASSERT(seg != NULL, ("%s: unable to get segment %d from VMCB",
233 __func__, ident));
234 *retval = seg->selector;
235 break;
236
237 case VM_REG_GUEST_GDTR:
238 case VM_REG_GUEST_IDTR:
239 /* GDTR and IDTR don't have segment selectors */
240 err = EINVAL;
241 break;
242 default:
243 err = EINVAL;
244 break;
245 }
246
247 return (err);
248 }
249
250 /*
251 * Write to segment selector, control and general purpose register of VMCB.
252 */
253 int
vmcb_write(struct svm_softc * sc,int vcpu,int ident,uint64_t val)254 vmcb_write(struct svm_softc *sc, int vcpu, int ident, uint64_t val)
255 {
256 struct vmcb *vmcb;
257 struct vmcb_state *state;
258 struct vmcb_segment *seg;
259 int err, dirtyseg;
260
261 vmcb = svm_get_vmcb(sc, vcpu);
262 state = &vmcb->state;
263 dirtyseg = 0;
264 err = 0;
265
266 if (VMCB_ACCESS_OK(ident))
267 return (vmcb_access(sc, vcpu, 1, ident, &val));
268
269 switch (ident) {
270 case VM_REG_GUEST_CR0:
271 state->cr0 = val;
272 svm_set_dirty(sc, vcpu, VMCB_CACHE_CR);
273 break;
274
275 case VM_REG_GUEST_CR2:
276 state->cr2 = val;
277 svm_set_dirty(sc, vcpu, VMCB_CACHE_CR2);
278 break;
279
280 case VM_REG_GUEST_CR3:
281 state->cr3 = val;
282 svm_set_dirty(sc, vcpu, VMCB_CACHE_CR);
283 break;
284
285 case VM_REG_GUEST_CR4:
286 state->cr4 = val;
287 svm_set_dirty(sc, vcpu, VMCB_CACHE_CR);
288 break;
289
290 case VM_REG_GUEST_DR6:
291 state->dr6 = val;
292 svm_set_dirty(sc, vcpu, VMCB_CACHE_DR);
293 break;
294
295 case VM_REG_GUEST_DR7:
296 state->dr7 = val;
297 svm_set_dirty(sc, vcpu, VMCB_CACHE_DR);
298 break;
299
300 case VM_REG_GUEST_EFER:
301 /* EFER_SVM must always be set when the guest is executing */
302 state->efer = val | EFER_SVM;
303 svm_set_dirty(sc, vcpu, VMCB_CACHE_CR);
304 break;
305
306 case VM_REG_GUEST_RAX:
307 state->rax = val;
308 break;
309
310 case VM_REG_GUEST_RFLAGS:
311 state->rflags = val;
312 break;
313
314 case VM_REG_GUEST_RIP:
315 state->rip = val;
316 break;
317
318 case VM_REG_GUEST_RSP:
319 state->rsp = val;
320 break;
321
322 case VM_REG_GUEST_CS:
323 case VM_REG_GUEST_DS:
324 case VM_REG_GUEST_ES:
325 case VM_REG_GUEST_SS:
326 dirtyseg = 1; /* FALLTHROUGH */
327 case VM_REG_GUEST_FS:
328 case VM_REG_GUEST_GS:
329 case VM_REG_GUEST_LDTR:
330 case VM_REG_GUEST_TR:
331 seg = vmcb_segptr(vmcb, ident);
332 KASSERT(seg != NULL, ("%s: unable to get segment %d from VMCB",
333 __func__, ident));
334 seg->selector = val;
335 if (dirtyseg)
336 svm_set_dirty(sc, vcpu, VMCB_CACHE_SEG);
337 break;
338
339 case VM_REG_GUEST_GDTR:
340 case VM_REG_GUEST_IDTR:
341 /* GDTR and IDTR don't have segment selectors */
342 err = EINVAL;
343 break;
344 default:
345 err = EINVAL;
346 break;
347 }
348
349 return (err);
350 }
351
352 int
vmcb_seg(struct vmcb * vmcb,int ident,struct vmcb_segment * seg2)353 vmcb_seg(struct vmcb *vmcb, int ident, struct vmcb_segment *seg2)
354 {
355 struct vmcb_segment *seg;
356
357 seg = vmcb_segptr(vmcb, ident);
358 if (seg != NULL) {
359 bcopy(seg, seg2, sizeof(struct vmcb_segment));
360 return (0);
361 } else {
362 return (EINVAL);
363 }
364 }
365
366 int
vmcb_setdesc(void * arg,int vcpu,int reg,struct seg_desc * desc)367 vmcb_setdesc(void *arg, int vcpu, int reg, struct seg_desc *desc)
368 {
369 struct vmcb *vmcb;
370 struct svm_softc *sc;
371 struct vmcb_segment *seg;
372 uint16_t attrib;
373
374 sc = arg;
375 vmcb = svm_get_vmcb(sc, vcpu);
376
377 seg = vmcb_segptr(vmcb, reg);
378 KASSERT(seg != NULL, ("%s: invalid segment descriptor %d",
379 __func__, reg));
380
381 seg->base = desc->base;
382 seg->limit = desc->limit;
383 if (reg != VM_REG_GUEST_GDTR && reg != VM_REG_GUEST_IDTR) {
384 /*
385 * Map seg_desc access to VMCB attribute format.
386 *
387 * SVM uses the 'P' bit in the segment attributes to indicate a
388 * NULL segment so clear it if the segment is marked unusable.
389 */
390 attrib = ((desc->access & 0xF000) >> 4) | (desc->access & 0xFF);
391 if (SEG_DESC_UNUSABLE(desc->access)) {
392 attrib &= ~0x80;
393 }
394 seg->attrib = attrib;
395 }
396
397 VCPU_CTR4(sc->vm, vcpu, "Setting desc %d: base (%#lx), limit (%#x), "
398 "attrib (%#x)", reg, seg->base, seg->limit, seg->attrib);
399
400 switch (reg) {
401 case VM_REG_GUEST_CS:
402 case VM_REG_GUEST_DS:
403 case VM_REG_GUEST_ES:
404 case VM_REG_GUEST_SS:
405 svm_set_dirty(sc, vcpu, VMCB_CACHE_SEG);
406 break;
407 case VM_REG_GUEST_GDTR:
408 case VM_REG_GUEST_IDTR:
409 svm_set_dirty(sc, vcpu, VMCB_CACHE_DT);
410 break;
411 default:
412 break;
413 }
414
415 return (0);
416 }
417
418 int
vmcb_getdesc(void * arg,int vcpu,int reg,struct seg_desc * desc)419 vmcb_getdesc(void *arg, int vcpu, int reg, struct seg_desc *desc)
420 {
421 struct vmcb *vmcb;
422 struct svm_softc *sc;
423 struct vmcb_segment *seg;
424
425 sc = arg;
426 vmcb = svm_get_vmcb(sc, vcpu);
427 seg = vmcb_segptr(vmcb, reg);
428 KASSERT(seg != NULL, ("%s: invalid segment descriptor %d",
429 __func__, reg));
430
431 desc->base = seg->base;
432 desc->limit = seg->limit;
433 desc->access = 0;
434
435 if (reg != VM_REG_GUEST_GDTR && reg != VM_REG_GUEST_IDTR) {
436 /* Map seg_desc access to VMCB attribute format */
437 desc->access = ((seg->attrib & 0xF00) << 4) |
438 (seg->attrib & 0xFF);
439
440 /*
441 * VT-x uses bit 16 to indicate a segment that has been loaded
442 * with a NULL selector (aka unusable). The 'desc->access'
443 * field is interpreted in the VT-x format by the
444 * processor-independent code.
445 *
446 * SVM uses the 'P' bit to convey the same information so
447 * convert it into the VT-x format. For more details refer to
448 * section "Segment State in the VMCB" in APMv2.
449 */
450 if (reg != VM_REG_GUEST_CS && reg != VM_REG_GUEST_TR) {
451 if ((desc->access & 0x80) == 0)
452 desc->access |= 0x10000; /* Unusable segment */
453 }
454 }
455
456 return (0);
457 }
458
459 #ifdef BHYVE_SNAPSHOT
460 int
vmcb_getany(struct svm_softc * sc,int vcpu,int ident,uint64_t * val)461 vmcb_getany(struct svm_softc *sc, int vcpu, int ident, uint64_t *val)
462 {
463 int error = 0;
464
465 if (vcpu < 0 || vcpu >= VM_MAXCPU) {
466 error = EINVAL;
467 goto err;
468 }
469
470 if (ident >= VM_REG_LAST) {
471 error = EINVAL;
472 goto err;
473 }
474
475 error = vmcb_read(sc, vcpu, ident, val);
476
477 err:
478 return (error);
479 }
480
481 int
vmcb_setany(struct svm_softc * sc,int vcpu,int ident,uint64_t val)482 vmcb_setany(struct svm_softc *sc, int vcpu, int ident, uint64_t val)
483 {
484 int error = 0;
485
486 if (vcpu < 0 || vcpu >= VM_MAXCPU) {
487 error = EINVAL;
488 goto err;
489 }
490
491 if (ident >= VM_REG_LAST) {
492 error = EINVAL;
493 goto err;
494 }
495
496 error = vmcb_write(sc, vcpu, ident, val);
497
498 err:
499 return (error);
500 }
501
502 int
vmcb_snapshot_desc(void * arg,int vcpu,int reg,struct vm_snapshot_meta * meta)503 vmcb_snapshot_desc(void *arg, int vcpu, int reg, struct vm_snapshot_meta *meta)
504 {
505 int ret;
506 struct seg_desc desc;
507
508 if (meta->op == VM_SNAPSHOT_SAVE) {
509 ret = vmcb_getdesc(arg, vcpu, reg, &desc);
510 if (ret != 0)
511 goto done;
512
513 SNAPSHOT_VAR_OR_LEAVE(desc.base, meta, ret, done);
514 SNAPSHOT_VAR_OR_LEAVE(desc.limit, meta, ret, done);
515 SNAPSHOT_VAR_OR_LEAVE(desc.access, meta, ret, done);
516 } else if (meta->op == VM_SNAPSHOT_RESTORE) {
517 SNAPSHOT_VAR_OR_LEAVE(desc.base, meta, ret, done);
518 SNAPSHOT_VAR_OR_LEAVE(desc.limit, meta, ret, done);
519 SNAPSHOT_VAR_OR_LEAVE(desc.access, meta, ret, done);
520
521 ret = vmcb_setdesc(arg, vcpu, reg, &desc);
522 if (ret != 0)
523 goto done;
524 } else {
525 ret = EINVAL;
526 goto done;
527 }
528
529 done:
530 return (ret);
531 }
532
533 int
vmcb_snapshot_any(struct svm_softc * sc,int vcpu,int ident,struct vm_snapshot_meta * meta)534 vmcb_snapshot_any(struct svm_softc *sc, int vcpu, int ident,
535 struct vm_snapshot_meta *meta)
536 {
537 int ret;
538 uint64_t val;
539
540 if (meta->op == VM_SNAPSHOT_SAVE) {
541 ret = vmcb_getany(sc, vcpu, ident, &val);
542 if (ret != 0)
543 goto done;
544
545 SNAPSHOT_VAR_OR_LEAVE(val, meta, ret, done);
546 } else if (meta->op == VM_SNAPSHOT_RESTORE) {
547 SNAPSHOT_VAR_OR_LEAVE(val, meta, ret, done);
548
549 ret = vmcb_setany(sc, vcpu, ident, val);
550 if (ret != 0)
551 goto done;
552 } else {
553 ret = EINVAL;
554 goto done;
555 }
556
557 done:
558 return (ret);
559 }
560 #endif
561