xref: /openbmc/qemu/accel/tcg/tcg-all.c (revision 587adaca)
1 /*
2  * QEMU System Emulator, accelerator interfaces
3  *
4  * Copyright (c) 2003-2008 Fabrice Bellard
5  * Copyright (c) 2014 Red Hat Inc.
6  *
7  * Permission is hereby granted, free of charge, to any person obtaining a copy
8  * of this software and associated documentation files (the "Software"), to deal
9  * in the Software without restriction, including without limitation the rights
10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11  * copies of the Software, and to permit persons to whom the Software is
12  * furnished to do so, subject to the following conditions:
13  *
14  * The above copyright notice and this permission notice shall be included in
15  * all copies or substantial portions of the Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
23  * THE SOFTWARE.
24  */
25 
26 #include "qemu/osdep.h"
27 #include "qemu-common.h"
28 #include "sysemu/tcg.h"
29 #include "sysemu/cpu-timers.h"
30 #include "tcg/tcg.h"
31 #include "qapi/error.h"
32 #include "qemu/error-report.h"
33 #include "qemu/accel.h"
34 #include "qapi/qapi-builtin-visit.h"
35 #include "qemu/units.h"
36 #if !defined(CONFIG_USER_ONLY)
37 #include "hw/boards.h"
38 #endif
39 #include "internal.h"
40 
41 struct TCGState {
42     AccelState parent_obj;
43 
44     bool mttcg_enabled;
45     int splitwx_enabled;
46     unsigned long tb_size;
47 };
48 typedef struct TCGState TCGState;
49 
50 #define TYPE_TCG_ACCEL ACCEL_CLASS_NAME("tcg")
51 
52 DECLARE_INSTANCE_CHECKER(TCGState, TCG_STATE,
53                          TYPE_TCG_ACCEL)
54 
55 /*
56  * We default to false if we know other options have been enabled
57  * which are currently incompatible with MTTCG. Otherwise when each
58  * guest (target) has been updated to support:
59  *   - atomic instructions
60  *   - memory ordering primitives (barriers)
61  * they can set the appropriate CONFIG flags in ${target}-softmmu.mak
62  *
63  * Once a guest architecture has been converted to the new primitives
64  * there are two remaining limitations to check.
65  *
66  * - The guest can't be oversized (e.g. 64 bit guest on 32 bit host)
67  * - The host must have a stronger memory order than the guest
68  *
69  * It may be possible in future to support strong guests on weak hosts
70  * but that will require tagging all load/stores in a guest with their
71  * implicit memory order requirements which would likely slow things
72  * down a lot.
73  */
74 
75 static bool check_tcg_memory_orders_compatible(void)
76 {
77 #if defined(TCG_GUEST_DEFAULT_MO) && defined(TCG_TARGET_DEFAULT_MO)
78     return (TCG_GUEST_DEFAULT_MO & ~TCG_TARGET_DEFAULT_MO) == 0;
79 #else
80     return false;
81 #endif
82 }
83 
84 static bool default_mttcg_enabled(void)
85 {
86     if (icount_enabled() || TCG_OVERSIZED_GUEST) {
87         return false;
88     } else {
89 #ifdef TARGET_SUPPORTS_MTTCG
90         return check_tcg_memory_orders_compatible();
91 #else
92         return false;
93 #endif
94     }
95 }
96 
97 static void tcg_accel_instance_init(Object *obj)
98 {
99     TCGState *s = TCG_STATE(obj);
100 
101     s->mttcg_enabled = default_mttcg_enabled();
102 
103     /* If debugging enabled, default "auto on", otherwise off. */
104 #if defined(CONFIG_DEBUG_TCG) && !defined(CONFIG_USER_ONLY)
105     s->splitwx_enabled = -1;
106 #else
107     s->splitwx_enabled = 0;
108 #endif
109 }
110 
111 bool mttcg_enabled;
112 
113 static int tcg_init_machine(MachineState *ms)
114 {
115     TCGState *s = TCG_STATE(current_accel());
116 #ifdef CONFIG_USER_ONLY
117     unsigned max_cpus = 1;
118 #else
119     unsigned max_cpus = ms->smp.max_cpus;
120 #endif
121 
122     tcg_allowed = true;
123     mttcg_enabled = s->mttcg_enabled;
124 
125     page_init();
126     tb_htable_init();
127     tcg_init(s->tb_size * MiB, s->splitwx_enabled, max_cpus);
128 
129 #if defined(CONFIG_SOFTMMU)
130     /*
131      * There's no guest base to take into account, so go ahead and
132      * initialize the prologue now.
133      */
134     tcg_prologue_init(tcg_ctx);
135 #endif
136 
137     return 0;
138 }
139 
140 static char *tcg_get_thread(Object *obj, Error **errp)
141 {
142     TCGState *s = TCG_STATE(obj);
143 
144     return g_strdup(s->mttcg_enabled ? "multi" : "single");
145 }
146 
147 static void tcg_set_thread(Object *obj, const char *value, Error **errp)
148 {
149     TCGState *s = TCG_STATE(obj);
150 
151     if (strcmp(value, "multi") == 0) {
152         if (TCG_OVERSIZED_GUEST) {
153             error_setg(errp, "No MTTCG when guest word size > hosts");
154         } else if (icount_enabled()) {
155             error_setg(errp, "No MTTCG when icount is enabled");
156         } else {
157 #ifndef TARGET_SUPPORTS_MTTCG
158             warn_report("Guest not yet converted to MTTCG - "
159                         "you may get unexpected results");
160 #endif
161             if (!check_tcg_memory_orders_compatible()) {
162                 warn_report("Guest expects a stronger memory ordering "
163                             "than the host provides");
164                 error_printf("This may cause strange/hard to debug errors\n");
165             }
166             s->mttcg_enabled = true;
167         }
168     } else if (strcmp(value, "single") == 0) {
169         s->mttcg_enabled = false;
170     } else {
171         error_setg(errp, "Invalid 'thread' setting %s", value);
172     }
173 }
174 
175 static void tcg_get_tb_size(Object *obj, Visitor *v,
176                             const char *name, void *opaque,
177                             Error **errp)
178 {
179     TCGState *s = TCG_STATE(obj);
180     uint32_t value = s->tb_size;
181 
182     visit_type_uint32(v, name, &value, errp);
183 }
184 
185 static void tcg_set_tb_size(Object *obj, Visitor *v,
186                             const char *name, void *opaque,
187                             Error **errp)
188 {
189     TCGState *s = TCG_STATE(obj);
190     uint32_t value;
191 
192     if (!visit_type_uint32(v, name, &value, errp)) {
193         return;
194     }
195 
196     s->tb_size = value;
197 }
198 
199 static bool tcg_get_splitwx(Object *obj, Error **errp)
200 {
201     TCGState *s = TCG_STATE(obj);
202     return s->splitwx_enabled;
203 }
204 
205 static void tcg_set_splitwx(Object *obj, bool value, Error **errp)
206 {
207     TCGState *s = TCG_STATE(obj);
208     s->splitwx_enabled = value;
209 }
210 
211 static void tcg_accel_class_init(ObjectClass *oc, void *data)
212 {
213     AccelClass *ac = ACCEL_CLASS(oc);
214     ac->name = "tcg";
215     ac->init_machine = tcg_init_machine;
216     ac->allowed = &tcg_allowed;
217 
218     object_class_property_add_str(oc, "thread",
219                                   tcg_get_thread,
220                                   tcg_set_thread);
221 
222     object_class_property_add(oc, "tb-size", "int",
223         tcg_get_tb_size, tcg_set_tb_size,
224         NULL, NULL);
225     object_class_property_set_description(oc, "tb-size",
226         "TCG translation block cache size");
227 
228     object_class_property_add_bool(oc, "split-wx",
229         tcg_get_splitwx, tcg_set_splitwx);
230     object_class_property_set_description(oc, "split-wx",
231         "Map jit pages into separate RW and RX regions");
232 }
233 
234 static const TypeInfo tcg_accel_type = {
235     .name = TYPE_TCG_ACCEL,
236     .parent = TYPE_ACCEL,
237     .instance_init = tcg_accel_instance_init,
238     .class_init = tcg_accel_class_init,
239     .instance_size = sizeof(TCGState),
240 };
241 
242 static void register_accel_types(void)
243 {
244     type_register_static(&tcg_accel_type);
245 }
246 
247 type_init(register_accel_types);
248