vmm_host.c revision 267427 
1/*-
2 * Copyright (c) 2012 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/vmm_host.c 267427 2014-06-12 19:58:12Z jhb $
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: stable/10/sys/amd64/vmm/vmm_host.c 267427 2014-06-12 19:58:12Z jhb $");
31
32#include <sys/param.h>
33#include <sys/pcpu.h>
34
35#include <machine/cpufunc.h>
36#include <machine/segments.h>
37#include <machine/specialreg.h>
38
39#include "vmm_host.h"
40
41static uint64_t vmm_host_efer, vmm_host_pat, vmm_host_cr0, vmm_host_cr4,
42	vmm_host_xcr0;
43static struct xsave_limits vmm_xsave_limits;
44
45void
46vmm_host_state_init(void)
47{
48	int regs[4];
49
50	vmm_host_efer = rdmsr(MSR_EFER);
51	vmm_host_pat = rdmsr(MSR_PAT);
52
53	/*
54	 * We always want CR0.TS to be set when the processor does a VM exit.
55	 *
56	 * With emulation turned on unconditionally after a VM exit, we are
57	 * able to trap inadvertent use of the FPU until the guest FPU state
58	 * has been safely squirreled away.
59	 */
60	vmm_host_cr0 = rcr0() | CR0_TS;
61
62	vmm_host_cr4 = rcr4();
63
64	/*
65	 * Only permit a guest to use XSAVE if the host is using
66	 * XSAVE.  Only permit a guest to use XSAVE features supported
67	 * by the host.  This ensures that the FPU state used by the
68	 * guest is always a subset of the saved guest FPU state.
69	 *
70	 * In addition, only permit known XSAVE features where the
71	 * rules for which features depend on other features is known
72	 * to properly emulate xsetbv.
73	 */
74	if (vmm_host_cr4 & CR4_XSAVE) {
75		vmm_xsave_limits.xsave_enabled = 1;
76		vmm_host_xcr0 = rxcr(0);
77		vmm_xsave_limits.xcr0_allowed = vmm_host_xcr0 &
78		    (XFEATURE_AVX | XFEATURE_MPX | XFEATURE_AVX512);
79
80		cpuid_count(0xd, 0x0, regs);
81		vmm_xsave_limits.xsave_max_size = regs[1];
82	}
83}
84
85uint64_t
86vmm_get_host_pat(void)
87{
88
89	return (vmm_host_pat);
90}
91
92uint64_t
93vmm_get_host_efer(void)
94{
95
96	return (vmm_host_efer);
97}
98
99uint64_t
100vmm_get_host_cr0(void)
101{
102
103	return (vmm_host_cr0);
104}
105
106uint64_t
107vmm_get_host_cr4(void)
108{
109
110	return (vmm_host_cr4);
111}
112
113uint64_t
114vmm_get_host_xcr0(void)
115{
116
117	return (vmm_host_xcr0);
118}
119
120uint64_t
121vmm_get_host_datasel(void)
122{
123
124	return (GSEL(GDATA_SEL, SEL_KPL));
125
126}
127
128uint64_t
129vmm_get_host_codesel(void)
130{
131
132	return (GSEL(GCODE_SEL, SEL_KPL));
133}
134
135uint64_t
136vmm_get_host_tsssel(void)
137{
138
139	return (GSEL(GPROC0_SEL, SEL_KPL));
140}
141
142uint64_t
143vmm_get_host_fsbase(void)
144{
145
146	return (0);
147}
148
149uint64_t
150vmm_get_host_idtrbase(void)
151{
152
153	return (r_idt.rd_base);
154}
155
156const struct xsave_limits *
157vmm_get_xsave_limits(void)
158{
159
160	return (&vmm_xsave_limits);
161}
162