1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2014, Neel Natu (neel@freebsd.org)
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 unmodified, this list of conditions, and the following
12 *    disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30#include "opt_bhyve_snapshot.h"
31
32#include <sys/param.h>
33#include <sys/errno.h>
34#include <sys/systm.h>
35
36#include <machine/cpufunc.h>
37#include <machine/specialreg.h>
38#include <machine/vmm.h>
39
40#include "svm.h"
41#include "vmcb.h"
42#include "svm_softc.h"
43#include "svm_msr.h"
44
45#ifndef MSR_AMDK8_IPM
46#define	MSR_AMDK8_IPM	0xc0010055
47#endif
48
49enum {
50	IDX_MSR_LSTAR,
51	IDX_MSR_CSTAR,
52	IDX_MSR_STAR,
53	IDX_MSR_SF_MASK,
54	HOST_MSR_NUM		/* must be the last enumeration */
55};
56
57static uint64_t host_msrs[HOST_MSR_NUM];
58
59void
60svm_msr_init(void)
61{
62	/*
63	 * It is safe to cache the values of the following MSRs because they
64	 * don't change based on curcpu, curproc or curthread.
65	 */
66	host_msrs[IDX_MSR_LSTAR] = rdmsr(MSR_LSTAR);
67	host_msrs[IDX_MSR_CSTAR] = rdmsr(MSR_CSTAR);
68	host_msrs[IDX_MSR_STAR] = rdmsr(MSR_STAR);
69	host_msrs[IDX_MSR_SF_MASK] = rdmsr(MSR_SF_MASK);
70}
71
72void
73svm_msr_guest_init(struct svm_softc *sc, struct svm_vcpu *vcpu)
74{
75	/*
76	 * All the MSRs accessible to the guest are either saved/restored by
77	 * hardware on every #VMEXIT/VMRUN (e.g., G_PAT) or are saved/restored
78	 * by VMSAVE/VMLOAD (e.g., MSR_GSBASE).
79	 *
80	 * There are no guest MSRs that are saved/restored "by hand" so nothing
81	 * more to do here.
82	 */
83	return;
84}
85
86void
87svm_msr_guest_enter(struct svm_vcpu *vcpu)
88{
89	/*
90	 * Save host MSRs (if any) and restore guest MSRs (if any).
91	 */
92}
93
94void
95svm_msr_guest_exit(struct svm_vcpu *vcpu)
96{
97	/*
98	 * Save guest MSRs (if any) and restore host MSRs.
99	 */
100	wrmsr(MSR_LSTAR, host_msrs[IDX_MSR_LSTAR]);
101	wrmsr(MSR_CSTAR, host_msrs[IDX_MSR_CSTAR]);
102	wrmsr(MSR_STAR, host_msrs[IDX_MSR_STAR]);
103	wrmsr(MSR_SF_MASK, host_msrs[IDX_MSR_SF_MASK]);
104
105	/* MSR_KGSBASE will be restored on the way back to userspace */
106}
107
108int
109svm_rdmsr(struct svm_vcpu *vcpu, u_int num, uint64_t *result, bool *retu)
110{
111	int error = 0;
112
113	switch (num) {
114	case MSR_MCG_CAP:
115	case MSR_MCG_STATUS:
116		*result = 0;
117		break;
118	case MSR_MTRRcap:
119	case MSR_MTRRdefType:
120	case MSR_MTRR4kBase ... MSR_MTRR4kBase + 7:
121	case MSR_MTRR16kBase ... MSR_MTRR16kBase + 1:
122	case MSR_MTRR64kBase:
123	case MSR_MTRRVarBase ... MSR_MTRRVarBase + (VMM_MTRR_VAR_MAX * 2) - 1:
124		if (vm_rdmtrr(&vcpu->mtrr, num, result) != 0) {
125			vm_inject_gp(vcpu->vcpu);
126		}
127		break;
128	case MSR_SYSCFG:
129	case MSR_AMDK8_IPM:
130	case MSR_EXTFEATURES:
131		*result = 0;
132		break;
133	default:
134		error = EINVAL;
135		break;
136	}
137
138	return (error);
139}
140
141int
142svm_wrmsr(struct svm_vcpu *vcpu, u_int num, uint64_t val, bool *retu)
143{
144	int error = 0;
145
146	switch (num) {
147	case MSR_MCG_CAP:
148	case MSR_MCG_STATUS:
149		break;		/* ignore writes */
150	case MSR_MTRRcap:
151	case MSR_MTRRdefType:
152	case MSR_MTRR4kBase ... MSR_MTRR4kBase + 7:
153	case MSR_MTRR16kBase ... MSR_MTRR16kBase + 1:
154	case MSR_MTRR64kBase:
155	case MSR_MTRRVarBase ... MSR_MTRRVarBase + (VMM_MTRR_VAR_MAX * 2) - 1:
156		if (vm_wrmtrr(&vcpu->mtrr, num, val) != 0) {
157			vm_inject_gp(vcpu->vcpu);
158		}
159		break;
160	case MSR_SYSCFG:
161		break;		/* Ignore writes */
162	case MSR_AMDK8_IPM:
163		/*
164		 * Ignore writes to the "Interrupt Pending Message" MSR.
165		 */
166		break;
167	case MSR_K8_UCODE_UPDATE:
168		/*
169		 * Ignore writes to microcode update register.
170		 */
171		break;
172#ifdef BHYVE_SNAPSHOT
173	case MSR_TSC:
174		svm_set_tsc_offset(vcpu, val - rdtsc());
175		break;
176#endif
177	case MSR_EXTFEATURES:
178		break;
179	default:
180		error = EINVAL;
181		break;
182	}
183
184	return (error);
185}
186