xref: /freebsd/sys/amd64/vmm/amd/svm_msr.c (revision 93e779a26c651610ac6e7986d67ecc9ed2cadcbf)
1 /*-
2  * Copyright (c) 2014, Neel Natu (neel@freebsd.org)
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("$FreeBSD$");
29 
30 #include <sys/param.h>
31 #include <sys/errno.h>
32 #include <sys/systm.h>
33 
34 #include <machine/cpufunc.h>
35 #include <machine/specialreg.h>
36 #include <machine/vmm.h>
37 
38 #include "svm.h"
39 #include "vmcb.h"
40 #include "svm_softc.h"
41 #include "svm_msr.h"
42 
43 #ifndef MSR_AMDK8_IPM
44 #define	MSR_AMDK8_IPM	0xc0010055
45 #endif
46 
47 enum {
48 	IDX_MSR_LSTAR,
49 	IDX_MSR_CSTAR,
50 	IDX_MSR_STAR,
51 	IDX_MSR_SF_MASK,
52 	HOST_MSR_NUM		/* must be the last enumeration */
53 };
54 
55 static uint64_t host_msrs[HOST_MSR_NUM];
56 
57 void
58 svm_msr_init(void)
59 {
60 	/*
61 	 * It is safe to cache the values of the following MSRs because they
62 	 * don't change based on curcpu, curproc or curthread.
63 	 */
64 	host_msrs[IDX_MSR_LSTAR] = rdmsr(MSR_LSTAR);
65 	host_msrs[IDX_MSR_CSTAR] = rdmsr(MSR_CSTAR);
66 	host_msrs[IDX_MSR_STAR] = rdmsr(MSR_STAR);
67 	host_msrs[IDX_MSR_SF_MASK] = rdmsr(MSR_SF_MASK);
68 }
69 
70 void
71 svm_msr_guest_init(struct svm_softc *sc, int vcpu)
72 {
73 	/*
74 	 * All the MSRs accessible to the guest are either saved/restored by
75 	 * hardware on every #VMEXIT/VMRUN (e.g., G_PAT) or are saved/restored
76 	 * by VMSAVE/VMLOAD (e.g., MSR_GSBASE).
77 	 *
78 	 * There are no guest MSRs that are saved/restored "by hand" so nothing
79 	 * more to do here.
80 	 */
81 	return;
82 }
83 
84 void
85 svm_msr_guest_enter(struct svm_softc *sc, int vcpu)
86 {
87 	/*
88 	 * Save host MSRs (if any) and restore guest MSRs (if any).
89 	 */
90 }
91 
92 void
93 svm_msr_guest_exit(struct svm_softc *sc, int vcpu)
94 {
95 	/*
96 	 * Save guest MSRs (if any) and restore host MSRs.
97 	 */
98 	wrmsr(MSR_LSTAR, host_msrs[IDX_MSR_LSTAR]);
99 	wrmsr(MSR_CSTAR, host_msrs[IDX_MSR_CSTAR]);
100 	wrmsr(MSR_STAR, host_msrs[IDX_MSR_STAR]);
101 	wrmsr(MSR_SF_MASK, host_msrs[IDX_MSR_SF_MASK]);
102 
103 	/* MSR_KGSBASE will be restored on the way back to userspace */
104 }
105 
106 int
107 svm_rdmsr(struct svm_softc *sc, int vcpu, u_int num, uint64_t *result,
108     bool *retu)
109 {
110 	int error = 0;
111 
112 	switch (num) {
113 	case MSR_MCG_CAP:
114 	case MSR_MCG_STATUS:
115 		*result = 0;
116 		break;
117 	case MSR_MTRRcap:
118 	case MSR_MTRRdefType:
119 	case MSR_MTRR4kBase ... MSR_MTRR4kBase + 8:
120 	case MSR_MTRR16kBase ... MSR_MTRR16kBase + 1:
121 	case MSR_MTRR64kBase:
122 	case MSR_SYSCFG:
123 		*result = 0;
124 		break;
125 	case MSR_AMDK8_IPM:
126 		*result = 0;
127 		break;
128 	default:
129 		error = EINVAL;
130 		break;
131 	}
132 
133 	return (error);
134 }
135 
136 int
137 svm_wrmsr(struct svm_softc *sc, int vcpu, u_int num, uint64_t val, bool *retu)
138 {
139 	int error = 0;
140 
141 	switch (num) {
142 	case MSR_MCG_CAP:
143 	case MSR_MCG_STATUS:
144 		break;		/* ignore writes */
145 	case MSR_MTRRcap:
146 		vm_inject_gp(sc->vm, vcpu);
147 		break;
148 	case MSR_MTRRdefType:
149 	case MSR_MTRR4kBase ... MSR_MTRR4kBase + 8:
150 	case MSR_MTRR16kBase ... MSR_MTRR16kBase + 1:
151 	case MSR_MTRR64kBase:
152 	case MSR_SYSCFG:
153 		break;		/* Ignore writes */
154 	case MSR_AMDK8_IPM:
155 		/*
156 		 * Ignore writes to the "Interrupt Pending Message" MSR.
157 		 */
158 		break;
159 	default:
160 		error = EINVAL;
161 		break;
162 	}
163 
164 	return (error);
165 }
166