vmx_msr.c revision 245678 
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: head/sys/amd64/vmm/intel/vmx_msr.c 245678 2013-01-20 03:42:49Z neel $
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: head/sys/amd64/vmm/intel/vmx_msr.c 245678 2013-01-20 03:42:49Z neel $");
31
32#include <sys/param.h>
33#include <sys/systm.h>
34
35#include <machine/cpufunc.h>
36
37#include "vmx_msr.h"
38
39static boolean_t
40vmx_ctl_allows_one_setting(uint64_t msr_val, int bitpos)
41{
42
43	if (msr_val & (1UL << (bitpos + 32)))
44		return (TRUE);
45	else
46		return (FALSE);
47}
48
49static boolean_t
50vmx_ctl_allows_zero_setting(uint64_t msr_val, int bitpos)
51{
52
53	if ((msr_val & (1UL << bitpos)) == 0)
54		return (TRUE);
55	else
56		return (FALSE);
57}
58
59uint32_t
60vmx_revision(void)
61{
62
63	return (rdmsr(MSR_VMX_BASIC) & 0xffffffff);
64}
65
66/*
67 * Generate a bitmask to be used for the VMCS execution control fields.
68 *
69 * The caller specifies what bits should be set to one in 'ones_mask'
70 * and what bits should be set to zero in 'zeros_mask'. The don't-care
71 * bits are set to the default value. The default values are obtained
72 * based on "Algorithm 3" in Section 27.5.1 "Algorithms for Determining
73 * VMX Capabilities".
74 *
75 * Returns zero on success and non-zero on error.
76 */
77int
78vmx_set_ctlreg(int ctl_reg, int true_ctl_reg, uint32_t ones_mask,
79	       uint32_t zeros_mask, uint32_t *retval)
80{
81	int i;
82	uint64_t val, trueval;
83	boolean_t true_ctls_avail, one_allowed, zero_allowed;
84
85	/* We cannot ask the same bit to be set to both '1' and '0' */
86	if ((ones_mask ^ zeros_mask) != (ones_mask | zeros_mask))
87		return (EINVAL);
88
89	if (rdmsr(MSR_VMX_BASIC) & (1UL << 55))
90		true_ctls_avail = TRUE;
91	else
92		true_ctls_avail = FALSE;
93
94	val = rdmsr(ctl_reg);
95	if (true_ctls_avail)
96		trueval = rdmsr(true_ctl_reg);		/* step c */
97	else
98		trueval = val;				/* step a */
99
100	for (i = 0; i < 32; i++) {
101		one_allowed = vmx_ctl_allows_one_setting(trueval, i);
102		zero_allowed = vmx_ctl_allows_zero_setting(trueval, i);
103
104		KASSERT(one_allowed || zero_allowed,
105			("invalid zero/one setting for bit %d of ctl 0x%0x, "
106			 "truectl 0x%0x\n", i, ctl_reg, true_ctl_reg));
107
108		if (zero_allowed && !one_allowed) {		/* b(i),c(i) */
109			if (ones_mask & (1 << i))
110				return (EINVAL);
111			*retval &= ~(1 << i);
112		} else if (one_allowed && !zero_allowed) {	/* b(i),c(i) */
113			if (zeros_mask & (1 << i))
114				return (EINVAL);
115			*retval |= 1 << i;
116		} else {
117			if (zeros_mask & (1 << i))	/* b(ii),c(ii) */
118				*retval &= ~(1 << i);
119			else if (ones_mask & (1 << i)) /* b(ii), c(ii) */
120				*retval |= 1 << i;
121			else if (!true_ctls_avail)
122				*retval &= ~(1 << i);	/* b(iii) */
123			else if (vmx_ctl_allows_zero_setting(val, i))/* c(iii)*/
124				*retval &= ~(1 << i);
125			else if (vmx_ctl_allows_one_setting(val, i)) /* c(iv) */
126				*retval |= 1 << i;
127			else {
128				panic("vmx_set_ctlreg: unable to determine "
129				      "correct value of ctl bit %d for msr "
130				      "0x%0x and true msr 0x%0x", i, ctl_reg,
131				      true_ctl_reg);
132			}
133		}
134	}
135
136	return (0);
137}
138
139void
140msr_bitmap_initialize(char *bitmap)
141{
142
143	memset(bitmap, 0xff, PAGE_SIZE);
144}
145
146int
147msr_bitmap_change_access(char *bitmap, u_int msr, int access)
148{
149	int byte, bit;
150
151	if (msr <= 0x00001FFF)
152		byte = msr / 8;
153	else if (msr >= 0xC0000000 && msr <= 0xC0001FFF)
154		byte = 1024 + (msr - 0xC0000000) / 8;
155	else
156		return (EINVAL);
157
158	bit = msr & 0x7;
159
160	if (access & MSR_BITMAP_ACCESS_READ)
161		bitmap[byte] &= ~(1 << bit);
162	else
163		bitmap[byte] |= 1 << bit;
164
165	byte += 2048;
166	if (access & MSR_BITMAP_ACCESS_WRITE)
167		bitmap[byte] &= ~(1 << bit);
168	else
169		bitmap[byte] |= 1 << bit;
170
171	return (0);
172}
173