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authorSanjay Lal <sanjayl@kymasys.com>2012-11-21 21:34:04 -0500
committerRalf Baechle <ralf@linux-mips.org>2013-05-07 21:55:35 -0400
commite685c689f3a84e5e24a5867afc5e7b5857efa3e4 (patch)
tree5771e2db6000f2fc8b125350d4b51424b90400cc
parent9843b030cc951bce4a4d9bec38b5155c96eb1740 (diff)
KVM/MIPS32: Privileged instruction/target branch emulation.
- The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat
-rw-r--r--arch/mips/kvm/kvm_mips_emul.c1829
-rw-r--r--arch/mips/kvm/kvm_mips_opcode.h24
2 files changed, 1853 insertions, 0 deletions
diff --git a/arch/mips/kvm/kvm_mips_emul.c b/arch/mips/kvm/kvm_mips_emul.c
new file mode 100644
index 000000000000..4b6274b47f33
--- /dev/null
+++ b/arch/mips/kvm/kvm_mips_emul.c
@@ -0,0 +1,1829 @@
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: Instruction/Exception emulation
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#include <linux/random.h>
20#include <asm/page.h>
21#include <asm/cacheflush.h>
22#include <asm/cpu-info.h>
23#include <asm/mmu_context.h>
24#include <asm/tlbflush.h>
25#include <asm/inst.h>
26
27#undef CONFIG_MIPS_MT
28#include <asm/r4kcache.h>
29#define CONFIG_MIPS_MT
30
31#include "kvm_mips_opcode.h"
32#include "kvm_mips_int.h"
33#include "kvm_mips_comm.h"
34
35#include "trace.h"
36
37/*
38 * Compute the return address and do emulate branch simulation, if required.
39 * This function should be called only in branch delay slot active.
40 */
41unsigned long kvm_compute_return_epc(struct kvm_vcpu *vcpu,
42 unsigned long instpc)
43{
44 unsigned int dspcontrol;
45 union mips_instruction insn;
46 struct kvm_vcpu_arch *arch = &vcpu->arch;
47 long epc = instpc;
48 long nextpc = KVM_INVALID_INST;
49
50 if (epc & 3)
51 goto unaligned;
52
53 /*
54 * Read the instruction
55 */
56 insn.word = kvm_get_inst((uint32_t *) epc, vcpu);
57
58 if (insn.word == KVM_INVALID_INST)
59 return KVM_INVALID_INST;
60
61 switch (insn.i_format.opcode) {
62 /*
63 * jr and jalr are in r_format format.
64 */
65 case spec_op:
66 switch (insn.r_format.func) {
67 case jalr_op:
68 arch->gprs[insn.r_format.rd] = epc + 8;
69 /* Fall through */
70 case jr_op:
71 nextpc = arch->gprs[insn.r_format.rs];
72 break;
73 }
74 break;
75
76 /*
77 * This group contains:
78 * bltz_op, bgez_op, bltzl_op, bgezl_op,
79 * bltzal_op, bgezal_op, bltzall_op, bgezall_op.
80 */
81 case bcond_op:
82 switch (insn.i_format.rt) {
83 case bltz_op:
84 case bltzl_op:
85 if ((long)arch->gprs[insn.i_format.rs] < 0)
86 epc = epc + 4 + (insn.i_format.simmediate << 2);
87 else
88 epc += 8;
89 nextpc = epc;
90 break;
91
92 case bgez_op:
93 case bgezl_op:
94 if ((long)arch->gprs[insn.i_format.rs] >= 0)
95 epc = epc + 4 + (insn.i_format.simmediate << 2);
96 else
97 epc += 8;
98 nextpc = epc;
99 break;
100
101 case bltzal_op:
102 case bltzall_op:
103 arch->gprs[31] = epc + 8;
104 if ((long)arch->gprs[insn.i_format.rs] < 0)
105 epc = epc + 4 + (insn.i_format.simmediate << 2);
106 else
107 epc += 8;
108 nextpc = epc;
109 break;
110
111 case bgezal_op:
112 case bgezall_op:
113 arch->gprs[31] = epc + 8;
114 if ((long)arch->gprs[insn.i_format.rs] >= 0)
115 epc = epc + 4 + (insn.i_format.simmediate << 2);
116 else
117 epc += 8;
118 nextpc = epc;
119 break;
120 case bposge32_op:
121 if (!cpu_has_dsp)
122 goto sigill;
123
124 dspcontrol = rddsp(0x01);
125
126 if (dspcontrol >= 32) {
127 epc = epc + 4 + (insn.i_format.simmediate << 2);
128 } else
129 epc += 8;
130 nextpc = epc;
131 break;
132 }
133 break;
134
135 /*
136 * These are unconditional and in j_format.
137 */
138 case jal_op:
139 arch->gprs[31] = instpc + 8;
140 case j_op:
141 epc += 4;
142 epc >>= 28;
143 epc <<= 28;
144 epc |= (insn.j_format.target << 2);
145 nextpc = epc;
146 break;
147
148 /*
149 * These are conditional and in i_format.
150 */
151 case beq_op:
152 case beql_op:
153 if (arch->gprs[insn.i_format.rs] ==
154 arch->gprs[insn.i_format.rt])
155 epc = epc + 4 + (insn.i_format.simmediate << 2);
156 else
157 epc += 8;
158 nextpc = epc;
159 break;
160
161 case bne_op:
162 case bnel_op:
163 if (arch->gprs[insn.i_format.rs] !=
164 arch->gprs[insn.i_format.rt])
165 epc = epc + 4 + (insn.i_format.simmediate << 2);
166 else
167 epc += 8;
168 nextpc = epc;
169 break;
170
171 case blez_op: /* not really i_format */
172 case blezl_op:
173 /* rt field assumed to be zero */
174 if ((long)arch->gprs[insn.i_format.rs] <= 0)
175 epc = epc + 4 + (insn.i_format.simmediate << 2);
176 else
177 epc += 8;
178 nextpc = epc;
179 break;
180
181 case bgtz_op:
182 case bgtzl_op:
183 /* rt field assumed to be zero */
184 if ((long)arch->gprs[insn.i_format.rs] > 0)
185 epc = epc + 4 + (insn.i_format.simmediate << 2);
186 else
187 epc += 8;
188 nextpc = epc;
189 break;
190
191 /*
192 * And now the FPA/cp1 branch instructions.
193 */
194 case cop1_op: