vmcb.c revision 267096 
1/*-
2 * Copyright (c) 2013 Anish Gupta (akgupt3@gmail.com)
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice unmodified, this list of conditions, and the following
10 *    disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: projects/bhyve_svm/sys/amd64/vmm/amd/vmcb.c 267096 2014-06-05 06:29:18Z grehan $");
29
30#include <sys/param.h>
31#include <sys/systm.h>
32#include <sys/cpuset.h>
33
34#include <machine/segments.h>
35#include <machine/specialreg.h>
36#include <machine/vmm.h>
37
38#include "vmcb.h"
39#include "svm.h"
40
41/*
42 * The VMCB aka Virtual Machine Control Block is a 4KB aligned page
43 * in memory that describes the virtual machine.
44 *
45 * The VMCB contains:
46 * - instructions or events in the guest to intercept
47 * - control bits that modify execution environment of the guest
48 * - guest processor state (e.g. general purpose registers)
49 */
50
51/*
52 * Initialize SVM h/w context i.e. the VMCB control and saved state areas.
53 */
54int
55svm_init_vmcb(struct vmcb *vmcb, uint64_t iopm_base_pa,
56	      uint64_t msrpm_base_pa, uint64_t np_pml4)
57{
58	struct vmcb_ctrl *ctrl;
59	struct vmcb_state *state;
60
61	ctrl = &vmcb->ctrl;
62	state = &vmcb->state;
63
64	ctrl->iopm_base_pa = iopm_base_pa;
65	ctrl->msrpm_base_pa = msrpm_base_pa;
66
67	/* Enable nested paging */
68	ctrl->np_enable = 1;
69	ctrl->n_cr3 = np_pml4;
70
71	/* EFER_SVM must always be set when the guest is executing */
72	state->efer = EFER_SVM;
73
74	return (0);
75}
76
77/*
78 * Set non-persistent fields of VMCB that are cleared by VMEXIT and must
79 * be set before restarting the guest (e.g. ASID, intercepts etc).
80 *
81 * APM2, Section 15.6, VMEXIT
82 */
83int
84svm_set_vmcb(struct vmcb *vmcb, uint8_t asid)
85{
86	struct vmcb_ctrl *ctrl;
87	struct vmcb_state *state;
88	uint16_t cr_shadow;
89
90	ctrl = &vmcb->ctrl;
91	state = &vmcb->state;
92
93	/*
94	 * Intercept accesses to the control registers that are not shadowed
95	 * in the VMCB - i.e. all except cr0, cr2, cr3, cr4 and cr8.
96	 */
97	cr_shadow = BIT(0) | BIT(2) | BIT(3) | BIT(4) | BIT(8);
98	ctrl->cr_write = ctrl->cr_read = ~cr_shadow;
99
100	/* Intercept Machine Check exceptions. */
101	ctrl->exception = BIT(IDT_MC);
102
103	 /* Intercept various events (for e.g. I/O, MSR and CPUID accesses) */
104	ctrl->ctrl1 =  VMCB_INTCPT_IO |
105		       VMCB_INTCPT_MSR |
106		       VMCB_INTCPT_HLT |
107		       VMCB_INTCPT_CPUID |
108		       VMCB_INTCPT_INTR |
109		       VMCB_INTCPT_VINTR |
110		       VMCB_INTCPT_INIT |
111		       VMCB_INTCPT_NMI |
112		       VMCB_INTCPT_SMI |
113		       VMCB_INTCPT_FERR_FREEZE |
114		       VMCB_INTCPT_SHUTDOWN;
115
116	/* VMRUN intercept is required, see APM2 */
117	ctrl->ctrl2 = VMCB_INTCPT_VMRUN;
118
119	/* ASID is cleared after every #VMEXIT. */
120	ctrl->asid = asid;
121
122	/*
123	 * Section 15.21.1, Interrupt Masking in EFLAGS
124	 * Section 15.21.2, Virtualizing APIC.TPR
125	 *
126	 * This must be set for %rflag and %cr8 isolation of guest and host.
127	 */
128	ctrl->v_intr_masking = 1;
129
130	 /* Enable Last Branch Record aka LBR for debugging */
131	ctrl->lbr_virt_en = 1;
132	state->dbgctl = BIT(0);
133
134	return (0);
135}
136
137/*
138 * Read from segment selector, control and general purpose register of VMCB.
139 */
140int
141vmcb_read(struct vmcb *vmcb, int ident, uint64_t *retval)
142{
143	struct vmcb_state *state;
144	struct vmcb_segment *seg;
145	int err;
146
147	state = &vmcb->state;
148	err = 0;
149
150	switch (ident) {
151	case VM_REG_GUEST_CR0:
152		*retval = state->cr0;
153		break;
154
155	case VM_REG_GUEST_CR2:
156		*retval = state->cr2;
157		break;
158
159	case VM_REG_GUEST_CR3:
160		*retval = state->cr3;
161		break;
162
163	case VM_REG_GUEST_CR4:
164		*retval = state->cr4;
165		break;
166
167	case VM_REG_GUEST_DR7:
168		*retval = state->dr7;
169		break;
170
171	case VM_REG_GUEST_EFER:
172		*retval = state->efer;
173		break;
174
175	case VM_REG_GUEST_RAX:
176		*retval = state->rax;
177		break;
178
179	case VM_REG_GUEST_RFLAGS:
180		*retval = state->rflags;
181		break;
182
183	case VM_REG_GUEST_RIP:
184		*retval = state->rip;
185		break;
186
187	case VM_REG_GUEST_RSP:
188		*retval = state->rsp;
189		break;
190
191	case VM_REG_GUEST_CS:
192	case VM_REG_GUEST_DS:
193	case VM_REG_GUEST_ES:
194	case VM_REG_GUEST_FS:
195	case VM_REG_GUEST_GS:
196	case VM_REG_GUEST_SS:
197	case VM_REG_GUEST_GDTR:
198	case VM_REG_GUEST_IDTR:
199	case VM_REG_GUEST_LDTR:
200	case VM_REG_GUEST_TR:
201		seg = vmcb_seg(vmcb, ident);
202		if (seg == NULL) {
203			ERR("Invalid seg type %d\n", ident);
204			err = EINVAL;
205			break;
206		}
207
208		*retval = seg->selector;
209		break;
210
211	default:
212		err =  EINVAL;
213		break;
214	}
215
216	return (err);
217}
218
219/*
220 * Write to segment selector, control and general purpose register of VMCB.
221 */
222int
223vmcb_write(struct vmcb *vmcb, int ident, uint64_t val)
224{
225	struct vmcb_state *state;
226	struct vmcb_segment *seg;
227	int err;
228
229	state = &vmcb->state;
230	err = 0;
231
232	switch (ident) {
233	case VM_REG_GUEST_CR0:
234		state->cr0 = val;
235		break;
236
237	case VM_REG_GUEST_CR2:
238		state->cr2 = val;
239		break;
240
241	case VM_REG_GUEST_CR3:
242		state->cr3 = val;
243		break;
244
245	case VM_REG_GUEST_CR4:
246		state->cr4 = val;
247		break;
248
249	case VM_REG_GUEST_DR7:
250		state->dr7 = val;
251		break;
252
253	case VM_REG_GUEST_EFER:
254		/* EFER_SVM must always be set when the guest is executing */
255		state->efer = val | EFER_SVM;
256		break;
257
258	case VM_REG_GUEST_RAX:
259		state->rax = val;
260		break;
261
262	case VM_REG_GUEST_RFLAGS:
263		state->rflags = val;
264		break;
265
266	case VM_REG_GUEST_RIP:
267		state->rip = val;
268		break;
269
270	case VM_REG_GUEST_RSP:
271		state->rsp = val;
272		break;
273
274	case VM_REG_GUEST_CS:
275	case VM_REG_GUEST_DS:
276	case VM_REG_GUEST_ES:
277	case VM_REG_GUEST_FS:
278	case VM_REG_GUEST_GS:
279	case VM_REG_GUEST_SS:
280	case VM_REG_GUEST_GDTR:
281	case VM_REG_GUEST_IDTR:
282	case VM_REG_GUEST_LDTR:
283	case VM_REG_GUEST_TR:
284		seg = vmcb_seg(vmcb, ident);
285		if (seg == NULL) {
286			ERR("Invalid segment type %d\n", ident);
287			err = EINVAL;
288			break;
289		}
290
291		seg->selector = val;
292		break;
293
294	default:
295		err = EINVAL;
296	}
297
298	return (err);
299}
300
301/*
302 * Return VMCB segment area.
303 */
304struct vmcb_segment *
305vmcb_seg(struct vmcb *vmcb, int type)
306{
307	struct vmcb_state *state;
308	struct vmcb_segment *seg;
309
310	state = &vmcb->state;
311
312	switch (type) {
313	case VM_REG_GUEST_CS:
314		seg = &state->cs;
315		break;
316
317	case VM_REG_GUEST_DS:
318		seg = &state->ds;
319		break;
320
321	case VM_REG_GUEST_ES:
322		seg = &state->es;
323		break;
324
325	case VM_REG_GUEST_FS:
326		seg = &state->fs;
327		break;
328
329	case VM_REG_GUEST_GS:
330		seg = &state->gs;
331		break;
332
333	case VM_REG_GUEST_SS:
334		seg = &state->ss;
335		break;
336
337	case VM_REG_GUEST_GDTR:
338		seg = &state->gdt;
339		break;
340
341	case VM_REG_GUEST_IDTR:
342		seg = &state->idt;
343		break;
344
345	case VM_REG_GUEST_LDTR:
346		seg = &state->ldt;
347		break;
348
349	case VM_REG_GUEST_TR:
350		seg = &state->tr;
351		break;
352
353	default:
354		seg = NULL;
355		break;
356	}
357
358	return (seg);
359}
360
361/*
362 * Inject an event to vcpu as described in section 15.20, "Event injection".
363 */
364int
365vmcb_eventinject(struct vmcb_ctrl *ctrl, int intr_type, int vector,
366		 uint32_t error, bool ec_valid)
367{
368	if (intr_type < VMCB_EVENTINJ_TYPE_INTR ||
369	    intr_type > VMCB_EVENTINJ_TYPE_INTn) {
370		ERR("Event:%d is not supported by SVM.\n", intr_type);
371		return (EINVAL);
372	}
373
374	if (intr_type == VMCB_EVENTINJ_TYPE_EXCEPTION && vector == IDT_NMI) {
375		ERR("NMI with Exception type is not possible.\n");
376		return (EINVAL);
377	}
378
379	ctrl->eventinj = (vector & VMCB_EVENTINJ_VECTOR_MASK) |
380			 (intr_type << VMCB_EVENTINJ_INTR_TYPE_SHIFT)  |
381			 (ec_valid ? VMCB_EVENTINJ_EC_VALID : 0) |
382			 VMCB_EVENTINJ_VALID;
383
384	ctrl->eventinj |= (uint64_t)error << VMCB_EVENTINJ_ERRCODE_SHIFT;
385
386	return (0);
387}
388