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Linux kernel mirror (for testing)
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linux
1/*
2* This file is subject to the terms and conditions of the GNU General Public
3* License. See the file "COPYING" in the main directory of this archive
4* for more details.
5*
6* KVM/MIPS: Binary Patching for privileged instructions, reduces traps.
7*
8* Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved.
9* Authors: Sanjay Lal <sanjayl@kymasys.com>
10*/
11
12#include <linux/errno.h>
13#include <linux/err.h>
14#include <linux/kvm_host.h>
15#include <linux/module.h>
16#include <linux/vmalloc.h>
17#include <linux/fs.h>
18#include <linux/bootmem.h>
19
20#include "kvm_mips_comm.h"
21
22#define SYNCI_TEMPLATE 0x041f0000
23#define SYNCI_BASE(x) (((x) >> 21) & 0x1f)
24#define SYNCI_OFFSET ((x) & 0xffff)
25
26#define LW_TEMPLATE 0x8c000000
27#define CLEAR_TEMPLATE 0x00000020
28#define SW_TEMPLATE 0xac000000
29
30int
31kvm_mips_trans_cache_index(uint32_t inst, uint32_t *opc,
32 struct kvm_vcpu *vcpu)
33{
34 int result = 0;
35 unsigned long kseg0_opc;
36 uint32_t synci_inst = 0x0;
37
38 /* Replace the CACHE instruction, with a NOP */
39 kseg0_opc =
40 CKSEG0ADDR(kvm_mips_translate_guest_kseg0_to_hpa
41 (vcpu, (unsigned long) opc));
42 memcpy((void *)kseg0_opc, (void *)&synci_inst, sizeof(uint32_t));
43 mips32_SyncICache(kseg0_opc, 32);
44
45 return result;
46}
47
48/*
49 * Address based CACHE instructions are transformed into synci(s). A little heavy
50 * for just D-cache invalidates, but avoids an expensive trap
51 */
52int
53kvm_mips_trans_cache_va(uint32_t inst, uint32_t *opc,
54 struct kvm_vcpu *vcpu)
55{
56 int result = 0;
57 unsigned long kseg0_opc;
58 uint32_t synci_inst = SYNCI_TEMPLATE, base, offset;
59
60 base = (inst >> 21) & 0x1f;
61 offset = inst & 0xffff;
62 synci_inst |= (base << 21);
63 synci_inst |= offset;
64
65 kseg0_opc =
66 CKSEG0ADDR(kvm_mips_translate_guest_kseg0_to_hpa
67 (vcpu, (unsigned long) opc));
68 memcpy((void *)kseg0_opc, (void *)&synci_inst, sizeof(uint32_t));
69 mips32_SyncICache(kseg0_opc, 32);
70
71 return result;
72}
73
74int
75kvm_mips_trans_mfc0(uint32_t inst, uint32_t *opc, struct kvm_vcpu *vcpu)
76{
77 int32_t rt, rd, sel;
78 uint32_t mfc0_inst;
79 unsigned long kseg0_opc, flags;
80
81 rt = (inst >> 16) & 0x1f;
82 rd = (inst >> 11) & 0x1f;
83 sel = inst & 0x7;
84
85 if ((rd == MIPS_CP0_ERRCTL) && (sel == 0)) {
86 mfc0_inst = CLEAR_TEMPLATE;
87 mfc0_inst |= ((rt & 0x1f) << 16);
88 } else {
89 mfc0_inst = LW_TEMPLATE;
90 mfc0_inst |= ((rt & 0x1f) << 16);
91 mfc0_inst |=
92 offsetof(struct mips_coproc,
93 reg[rd][sel]) + offsetof(struct kvm_mips_commpage,
94 cop0);
95 }
96
97 if (KVM_GUEST_KSEGX(opc) == KVM_GUEST_KSEG0) {
98 kseg0_opc =
99 CKSEG0ADDR(kvm_mips_translate_guest_kseg0_to_hpa
100 (vcpu, (unsigned long) opc));
101 memcpy((void *)kseg0_opc, (void *)&mfc0_inst, sizeof(uint32_t));
102 mips32_SyncICache(kseg0_opc, 32);
103 } else if (KVM_GUEST_KSEGX((unsigned long) opc) == KVM_GUEST_KSEG23) {
104 local_irq_save(flags);
105 memcpy((void *)opc, (void *)&mfc0_inst, sizeof(uint32_t));
106 mips32_SyncICache((unsigned long) opc, 32);
107 local_irq_restore(flags);
108 } else {
109 kvm_err("%s: Invalid address: %p\n", __func__, opc);
110 return -EFAULT;
111 }
112
113 return 0;
114}
115
116int
117kvm_mips_trans_mtc0(uint32_t inst, uint32_t *opc, struct kvm_vcpu *vcpu)
118{
119 int32_t rt, rd, sel;
120 uint32_t mtc0_inst = SW_TEMPLATE;
121 unsigned long kseg0_opc, flags;
122
123 rt = (inst >> 16) & 0x1f;
124 rd = (inst >> 11) & 0x1f;
125 sel = inst & 0x7;
126
127 mtc0_inst |= ((rt & 0x1f) << 16);
128 mtc0_inst |=
129 offsetof(struct mips_coproc,
130 reg[rd][sel]) + offsetof(struct kvm_mips_commpage, cop0);
131
132 if (KVM_GUEST_KSEGX(opc) == KVM_GUEST_KSEG0) {
133 kseg0_opc =
134 CKSEG0ADDR(kvm_mips_translate_guest_kseg0_to_hpa
135 (vcpu, (unsigned long) opc));
136 memcpy((void *)kseg0_opc, (void *)&mtc0_inst, sizeof(uint32_t));
137 mips32_SyncICache(kseg0_opc, 32);
138 } else if (KVM_GUEST_KSEGX((unsigned long) opc) == KVM_GUEST_KSEG23) {
139 local_irq_save(flags);
140 memcpy((void *)opc, (void *)&mtc0_inst, sizeof(uint32_t));
141 mips32_SyncICache((unsigned long) opc, 32);
142 local_irq_restore(flags);
143 } else {
144 kvm_err("%s: Invalid address: %p\n", __func__, opc);
145 return -EFAULT;
146 }
147
148 return 0;
149}