xref: /illumos-gate/usr/src/uts/intel/io/vmm/vmm_host.c (revision 32640292)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2012 NetApp, Inc.
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, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 /*
29  * This file and its contents are supplied under the terms of the
30  * Common Development and Distribution License ("CDDL"), version 1.0.
31  * You may only use this file in accordance with the terms of version
32  * 1.0 of the CDDL.
33  *
34  * A full copy of the text of the CDDL should have accompanied this
35  * source.  A copy of the CDDL is also available via the Internet at
36  * http://www.illumos.org/license/CDDL.
37  *
38  * Copyright 2013 Pluribus Networks Inc.
39  */
40 
41 #include <sys/cdefs.h>
42 
43 #include <sys/param.h>
44 #include <sys/pcpu.h>
45 
46 #include <machine/cpufunc.h>
47 #include <machine/segments.h>
48 #include <machine/specialreg.h>
49 
50 #include "vmm_host.h"
51 
52 static uint64_t vmm_host_efer, vmm_host_pat, vmm_host_cr0, vmm_host_cr4,
53 	vmm_host_xcr0;
54 static struct xsave_limits vmm_xsave_limits;
55 
56 void
vmm_host_state_init(void)57 vmm_host_state_init(void)
58 {
59 	unsigned int regs[4];
60 
61 	vmm_host_efer = rdmsr(MSR_EFER);
62 	vmm_host_pat = rdmsr(MSR_PAT);
63 
64 	/*
65 	 * We always want CR0.TS to be set when the processor does a VM exit.
66 	 *
67 	 * With emulation turned on unconditionally after a VM exit, we are
68 	 * able to trap inadvertent use of the FPU until the guest FPU state
69 	 * has been safely squirreled away.
70 	 */
71 	vmm_host_cr0 = rcr0() | CR0_TS;
72 
73 	/*
74 	 * On non-PCID or PCID but without INVPCID support machines,
75 	 * we flush kernel i.e. global TLB entries, by temporary
76 	 * clearing the CR4.PGE bit, see invltlb_glob().  If
77 	 * preemption occurs at the wrong time, cached vmm_host_cr4
78 	 * might store the value with CR4.PGE cleared.  Since FreeBSD
79 	 * requires support for PG_G on amd64, just set it
80 	 * unconditionally.
81 	 */
82 	vmm_host_cr4 = rcr4() | CR4_PGE;
83 
84 	/*
85 	 * Only permit a guest to use XSAVE if the host is using
86 	 * XSAVE.  Only permit a guest to use XSAVE features supported
87 	 * by the host.  This ensures that the FPU state used by the
88 	 * guest is always a subset of the saved guest FPU state.
89 	 *
90 	 * In addition, only permit known XSAVE features where the
91 	 * rules for which features depend on other features is known
92 	 * to properly emulate xsetbv.
93 	 */
94 	if (vmm_host_cr4 & CR4_XSAVE) {
95 		vmm_xsave_limits.xsave_enabled = 1;
96 		vmm_host_xcr0 = rxcr(0);
97 		vmm_xsave_limits.xcr0_allowed = vmm_host_xcr0 &
98 		    (XFEATURE_AVX | XFEATURE_MPX | XFEATURE_AVX512);
99 
100 		cpuid_count(0xd, 0x0, regs);
101 		vmm_xsave_limits.xsave_max_size = regs[1];
102 	}
103 }
104 
105 uint64_t
vmm_get_host_pat(void)106 vmm_get_host_pat(void)
107 {
108 
109 	return (vmm_host_pat);
110 }
111 
112 uint64_t
vmm_get_host_efer(void)113 vmm_get_host_efer(void)
114 {
115 
116 	return (vmm_host_efer);
117 }
118 
119 uint64_t
vmm_get_host_cr0(void)120 vmm_get_host_cr0(void)
121 {
122 
123 	return (vmm_host_cr0);
124 }
125 
126 uint64_t
vmm_get_host_cr4(void)127 vmm_get_host_cr4(void)
128 {
129 
130 	return (vmm_host_cr4);
131 }
132 
133 uint64_t
vmm_get_host_xcr0(void)134 vmm_get_host_xcr0(void)
135 {
136 
137 	return (vmm_host_xcr0);
138 }
139 
140 uint64_t
vmm_get_host_datasel(void)141 vmm_get_host_datasel(void)
142 {
143 	return (SEL_GDT(GDT_KDATA, SEL_KPL));
144 }
145 
146 uint64_t
vmm_get_host_codesel(void)147 vmm_get_host_codesel(void)
148 {
149 	return (SEL_GDT(GDT_KCODE, SEL_KPL));
150 }
151 
152 uint64_t
vmm_get_host_tsssel(void)153 vmm_get_host_tsssel(void)
154 {
155 	return (SEL_GDT(GDT_KTSS, SEL_KPL));
156 }
157 
158 uint64_t
vmm_get_host_fsbase(void)159 vmm_get_host_fsbase(void)
160 {
161 	return (rdmsr(MSR_FSBASE));
162 }
163 
164 uint64_t
vmm_get_host_idtrbase(void)165 vmm_get_host_idtrbase(void)
166 {
167 	desctbr_t idtr;
168 
169 	rd_idtr(&idtr);
170 	return (idtr.dtr_base);
171 }
172 
173 const struct xsave_limits *
vmm_get_xsave_limits(void)174 vmm_get_xsave_limits(void)
175 {
176 
177 	return (&vmm_xsave_limits);
178 }
179