1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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 __FBSDID("$FreeBSD$");
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
39 #include "vmm_ktr.h"
40
41 #include "vmcb.h"
42 #include "svm.h"
43 #include "svm_softc.h"
44
45 /*
46 * The VMCB aka Virtual Machine Control Block is a 4KB aligned page
47 * in memory that describes the virtual machine.
48 *
49 * The VMCB contains:
50 * - instructions or events in the guest to intercept
51 * - control bits that modify execution environment of the guest
52 * - guest processor state (e.g. general purpose registers)
53 */
54
55 /*
56 * Return VMCB segment area.
57 */
58 static struct vmcb_segment *
vmcb_segptr(struct vmcb * vmcb,int type)59 vmcb_segptr(struct vmcb *vmcb, int type)
60 {
61 struct vmcb_state *state;
62 struct vmcb_segment *seg;
63
64 state = &vmcb->state;
65
66 switch (type) {
67 case VM_REG_GUEST_CS:
68 seg = &state->cs;
69 break;
70
71 case VM_REG_GUEST_DS:
72 seg = &state->ds;
73 break;
74
75 case VM_REG_GUEST_ES:
76 seg = &state->es;
77 break;
78
79 case VM_REG_GUEST_FS:
80 seg = &state->fs;
81 break;
82
83 case VM_REG_GUEST_GS:
84 seg = &state->gs;
85 break;
86
87 case VM_REG_GUEST_SS:
88 seg = &state->ss;
89 break;
90
91 case VM_REG_GUEST_GDTR:
92 seg = &state->gdt;
93 break;
94
95 case VM_REG_GUEST_IDTR:
96 seg = &state->idt;
97 break;
98
99 case VM_REG_GUEST_LDTR:
100 seg = &state->ldt;
101 break;
102
103 case VM_REG_GUEST_TR:
104 seg = &state->tr;
105 break;
106
107 default:
108 seg = NULL;
109 break;
110 }
111
112 return (seg);
113 }
114
115 static int
vmcb_access(struct svm_softc * softc,int vcpu,int write,int ident,uint64_t * val)116 vmcb_access(struct svm_softc *softc, int vcpu, int write, int ident,
117 uint64_t *val)
118 {
119 struct vmcb *vmcb;
120 int off, bytes;
121 char *ptr;
122
123 vmcb = svm_get_vmcb(softc, 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 if (write)
140 memcpy(ptr + off, val, bytes);
141 else
142 memcpy(val, ptr + off, bytes);
143 break;
144 default:
145 VCPU_CTR1(softc->vm, vcpu,
146 "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(softc, 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_softc * sc,int vcpu,int ident,uint64_t * retval)161 vmcb_read(struct svm_softc *sc, int 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(sc, vcpu);
169 state = &vmcb->state;
170 err = 0;
171
172 if (VMCB_ACCESS_OK(ident))
173 return (vmcb_access(sc, 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_softc * sc,int vcpu,int ident,uint64_t val)251 vmcb_write(struct svm_softc *sc, int 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(sc, vcpu);
259 state = &vmcb->state;
260 dirtyseg = 0;
261 err = 0;
262
263 if (VMCB_ACCESS_OK(ident))
264 return (vmcb_access(sc, vcpu, 1, ident, &val));
265
266 switch (ident) {
267 case VM_REG_GUEST_CR0:
268 state->cr0 = val;
269 svm_set_dirty(sc, vcpu, VMCB_CACHE_CR);
270 break;
271
272 case VM_REG_GUEST_CR2:
273 state->cr2 = val;
274 svm_set_dirty(sc, vcpu, VMCB_CACHE_CR2);
275 break;
276
277 case VM_REG_GUEST_CR3:
278 state->cr3 = val;
279 svm_set_dirty(sc, vcpu, VMCB_CACHE_CR);
280 break;
281
282 case VM_REG_GUEST_CR4:
283 state->cr4 = val;
284 svm_set_dirty(sc, vcpu, VMCB_CACHE_CR);
285 break;
286
287 case VM_REG_GUEST_DR6:
288 state->dr6 = val;
289 svm_set_dirty(sc, vcpu, VMCB_CACHE_DR);
290 break;
291
292 case VM_REG_GUEST_DR7:
293 state->dr7 = val;
294 svm_set_dirty(sc, 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(sc, 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(sc, 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(void * arg,int vcpu,int reg,struct seg_desc * desc)364 vmcb_setdesc(void *arg, int vcpu, int reg, struct seg_desc *desc)
365 {
366 struct vmcb *vmcb;
367 struct svm_softc *sc;
368 struct vmcb_segment *seg;
369 uint16_t attrib;
370
371 sc = arg;
372 vmcb = svm_get_vmcb(sc, vcpu);
373
374 seg = vmcb_segptr(vmcb, reg);
375 KASSERT(seg != NULL, ("%s: invalid segment descriptor %d",
376 __func__, reg));
377
378 seg->base = desc->base;
379 seg->limit = desc->limit;
380 if (reg != VM_REG_GUEST_GDTR && reg != VM_REG_GUEST_IDTR) {
381 /*
382 * Map seg_desc access to VMCB attribute format.
383 *
384 * SVM uses the 'P' bit in the segment attributes to indicate a
385 * NULL segment so clear it if the segment is marked unusable.
386 */
387 attrib = ((desc->access & 0xF000) >> 4) | (desc->access & 0xFF);
388 if (SEG_DESC_UNUSABLE(desc->access)) {
389 attrib &= ~0x80;
390 }
391 seg->attrib = attrib;
392 }
393
394 VCPU_CTR4(sc->vm, vcpu, "Setting desc %d: base (%#lx), limit (%#x), "
395 "attrib (%#x)", reg, seg->base, seg->limit, seg->attrib);
396
397 switch (reg) {
398 case VM_REG_GUEST_CS:
399 case VM_REG_GUEST_DS:
400 case VM_REG_GUEST_ES:
401 case VM_REG_GUEST_SS:
402 svm_set_dirty(sc, vcpu, VMCB_CACHE_SEG);
403 break;
404 case VM_REG_GUEST_GDTR:
405 case VM_REG_GUEST_IDTR:
406 svm_set_dirty(sc, vcpu, VMCB_CACHE_DT);
407 break;
408 default:
409 break;
410 }
411
412 return (0);
413 }
414
415 int
vmcb_getdesc(void * arg,int vcpu,int reg,struct seg_desc * desc)416 vmcb_getdesc(void *arg, int vcpu, int reg, struct seg_desc *desc)
417 {
418 struct vmcb *vmcb;
419 struct svm_softc *sc;
420 struct vmcb_segment *seg;
421
422 sc = arg;
423 vmcb = svm_get_vmcb(sc, vcpu);
424 seg = vmcb_segptr(vmcb, reg);
425 KASSERT(seg != NULL, ("%s: invalid segment descriptor %d",
426 __func__, reg));
427
428 desc->base = seg->base;
429 desc->limit = seg->limit;
430 desc->access = 0;
431
432 if (reg != VM_REG_GUEST_GDTR && reg != VM_REG_GUEST_IDTR) {
433 /* Map seg_desc access to VMCB attribute format */
434 desc->access = ((seg->attrib & 0xF00) << 4) |
435 (seg->attrib & 0xFF);
436
437 /*
438 * VT-x uses bit 16 to indicate a segment that has been loaded
439 * with a NULL selector (aka unusable). The 'desc->access'
440 * field is interpreted in the VT-x format by the
441 * processor-independent code.
442 *
443 * SVM uses the 'P' bit to convey the same information so
444 * convert it into the VT-x format. For more details refer to
445 * section "Segment State in the VMCB" in APMv2.
446 */
447 if (reg != VM_REG_GUEST_CS && reg != VM_REG_GUEST_TR) {
448 if ((desc->access & 0x80) == 0)
449 desc->access |= 0x10000; /* Unusable segment */
450 }
451 }
452
453 return (0);
454 }
455