accel/tcg/tcg-all.c

   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 "sysemu/tcg.h"
  28 #include "sysemu/replay.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 int tcg_gdbstub_supported_sstep_flags(void)
 212 {
 213     /*
 214      * In replay mode all events will come from the log and can't be
 215      * suppressed otherwise we would break determinism. However as those
 216      * events are tied to the number of executed instructions we won't see
 217      * them occurring every time we single step.
 218      */
 219     if (replay_mode != REPLAY_MODE_NONE) {
 220         return SSTEP_ENABLE;
 221     } else {
 222         return SSTEP_ENABLE | SSTEP_NOIRQ | SSTEP_NOTIMER;
 223     }
 224 }
 225
 226 static void tcg_accel_class_init(ObjectClass *oc, void *data)
 227 {
 228     AccelClass *ac = ACCEL_CLASS(oc);
 229     ac->name = "tcg";
 230     ac->init_machine = tcg_init_machine;
 231     ac->allowed = &tcg_allowed;
 232     ac->gdbstub_supported_sstep_flags = tcg_gdbstub_supported_sstep_flags;
 233
 234     object_class_property_add_str(oc, "thread",
 235                                   tcg_get_thread,
 236                                   tcg_set_thread);
 237
 238     object_class_property_add(oc, "tb-size", "int",
 239         tcg_get_tb_size, tcg_set_tb_size,
 240         NULL, NULL);
 241     object_class_property_set_description(oc, "tb-size",
 242         "TCG translation block cache size");
 243
 244     object_class_property_add_bool(oc, "split-wx",
 245         tcg_get_splitwx, tcg_set_splitwx);
 246     object_class_property_set_description(oc, "split-wx",
 247         "Map jit pages into separate RW and RX regions");
 248 }
 249
 250 static const TypeInfo tcg_accel_type = {
 251     .name = TYPE_TCG_ACCEL,
 252     .parent = TYPE_ACCEL,
 253     .instance_init = tcg_accel_instance_init,
 254     .class_init = tcg_accel_class_init,
 255     .instance_size = sizeof(TCGState),
 256 };
 257 module_obj(TYPE_TCG_ACCEL);
 258
 259 static void register_accel_types(void)
 260 {
 261     type_register_static(&tcg_accel_type);
 262 }
 263
 264 type_init(register_accel_types);