vmx_msr.c revision 270159 
1/*-
2 * Copyright (c) 2011 NetApp, Inc.
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, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: stable/10/sys/amd64/vmm/intel/vmx_msr.c 270159 2014-08-19 01:20:24Z grehan $
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: stable/10/sys/amd64/vmm/intel/vmx_msr.c 270159 2014-08-19 01:20:24Z grehan $");
31
32#include <sys/param.h>
33#include <sys/systm.h>
34
35#include <machine/cpufunc.h>
36#include <machine/specialreg.h>
37
38#include "vmx_msr.h"
39
40static boolean_t
41vmx_ctl_allows_one_setting(uint64_t msr_val, int bitpos)
42{
43
44	if (msr_val & (1UL << (bitpos + 32)))
45		return (TRUE);
46	else
47		return (FALSE);
48}
49
50static boolean_t
51vmx_ctl_allows_zero_setting(uint64_t msr_val, int bitpos)
52{
53
54	if ((msr_val & (1UL << bitpos)) == 0)
55		return (TRUE);
56	else
57		return (FALSE);
58}
59
60uint32_t
61vmx_revision(void)
62{
63
64	return (rdmsr(MSR_VMX_BASIC) & 0xffffffff);
65}
66
67/*
68 * Generate a bitmask to be used for the VMCS execution control fields.
69 *
70 * The caller specifies what bits should be set to one in 'ones_mask'
71 * and what bits should be set to zero in 'zeros_mask'. The don't-care
72 * bits are set to the default value. The default values are obtained
73 * based on "Algorithm 3" in Section 27.5.1 "Algorithms for Determining
74 * VMX Capabilities".
75 *
76 * Returns zero on success and non-zero on error.
77 */
78int
79vmx_set_ctlreg(int ctl_reg, int true_ctl_reg, uint32_t ones_mask,
80	       uint32_t zeros_mask, uint32_t *retval)
81{
82	int i;
83	uint64_t val, trueval;
84	boolean_t true_ctls_avail, one_allowed, zero_allowed;
85
86	/* We cannot ask the same bit to be set to both '1' and '0' */
87	if ((ones_mask ^ zeros_mask) != (ones_mask | zeros_mask))
88		return (EINVAL);
89
90	if (rdmsr(MSR_VMX_BASIC) & (1UL << 55))
91		true_ctls_avail = TRUE;
92	else
93		true_ctls_avail = FALSE;
94
95	val = rdmsr(ctl_reg);
96	if (true_ctls_avail)
97		trueval = rdmsr(true_ctl_reg);		/* step c */
98	else
99		trueval = val;				/* step a */
100
101	for (i = 0; i < 32; i++) {
102		one_allowed = vmx_ctl_allows_one_setting(trueval, i);
103		zero_allowed = vmx_ctl_allows_zero_setting(trueval, i);
104
105		KASSERT(one_allowed || zero_allowed,
106			("invalid zero/one setting for bit %d of ctl 0x%0x, "
107			 "truectl 0x%0x\n", i, ctl_reg, true_ctl_reg));
108
109		if (zero_allowed && !one_allowed) {		/* b(i),c(i) */
110			if (ones_mask & (1 << i))
111				return (EINVAL);
112			*retval &= ~(1 << i);
113		} else if (one_allowed && !zero_allowed) {	/* b(i),c(i) */
114			if (zeros_mask & (1 << i))
115				return (EINVAL);
116			*retval |= 1 << i;
117		} else {
118			if (zeros_mask & (1 << i))	/* b(ii),c(ii) */
119				*retval &= ~(1 << i);
120			else if (ones_mask & (1 << i)) /* b(ii), c(ii) */
121				*retval |= 1 << i;
122			else if (!true_ctls_avail)
123				*retval &= ~(1 << i);	/* b(iii) */
124			else if (vmx_ctl_allows_zero_setting(val, i))/* c(iii)*/
125				*retval &= ~(1 << i);
126			else if (vmx_ctl_allows_one_setting(val, i)) /* c(iv) */
127				*retval |= 1 << i;
128			else {
129				panic("vmx_set_ctlreg: unable to determine "
130				      "correct value of ctl bit %d for msr "
131				      "0x%0x and true msr 0x%0x", i, ctl_reg,
132				      true_ctl_reg);
133			}
134		}
135	}
136
137	return (0);
138}
139
140void
141msr_bitmap_initialize(char *bitmap)
142{
143
144	memset(bitmap, 0xff, PAGE_SIZE);
145}
146
147int
148msr_bitmap_change_access(char *bitmap, u_int msr, int access)
149{
150	int byte, bit;
151
152	if (msr <= 0x00001FFF)
153		byte = msr / 8;
154	else if (msr >= 0xC0000000 && msr <= 0xC0001FFF)
155		byte = 1024 + (msr - 0xC0000000) / 8;
156	else
157		return (EINVAL);
158
159	bit = msr & 0x7;
160
161	if (access & MSR_BITMAP_ACCESS_READ)
162		bitmap[byte] &= ~(1 << bit);
163	else
164		bitmap[byte] |= 1 << bit;
165
166	byte += 2048;
167	if (access & MSR_BITMAP_ACCESS_WRITE)
168		bitmap[byte] &= ~(1 << bit);
169	else
170		bitmap[byte] |= 1 << bit;
171
172	return (0);
173}
174