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 "exec/replay-core.h"
  29 #include "sysemu/cpu-timers.h"
  30 #include "tcg/tcg.h"
  31 #include "tcg/oversized-guest.h"
  32 #include "qapi/error.h"
  33 #include "qemu/error-report.h"
  34 #include "qemu/accel.h"
  35 #include "qemu/atomic.h"
  36 #include "qapi/qapi-builtin-visit.h"
  37 #include "qemu/units.h"
  38 #if !defined(CONFIG_USER_ONLY)
  39 #include "hw/boards.h"
  40 #endif
  41 #include "internal.h"
  42
  43 struct TCGState {
  44     AccelState parent_obj;
  45
  46     bool mttcg_enabled;
  47     bool one_insn_per_tb;
  48     int splitwx_enabled;
  49     unsigned long tb_size;
  50 };
  51 typedef struct TCGState TCGState;
  52
  53 #define TYPE_TCG_ACCEL ACCEL_CLASS_NAME("tcg")
  54
  55 DECLARE_INSTANCE_CHECKER(TCGState, TCG_STATE,
  56                          TYPE_TCG_ACCEL)
  57
  58 /*
  59  * We default to false if we know other options have been enabled
  60  * which are currently incompatible with MTTCG. Otherwise when each
  61  * guest (target) has been updated to support:
  62  *   - atomic instructions
  63  *   - memory ordering primitives (barriers)
  64  * they can set the appropriate CONFIG flags in ${target}-softmmu.mak
  65  *
  66  * Once a guest architecture has been converted to the new primitives
  67  * there are two remaining limitations to check.
  68  *
  69  * - The guest can't be oversized (e.g. 64 bit guest on 32 bit host)
  70  * - The host must have a stronger memory order than the guest
  71  *
  72  * It may be possible in future to support strong guests on weak hosts
  73  * but that will require tagging all load/stores in a guest with their
  74  * implicit memory order requirements which would likely slow things
  75  * down a lot.
  76  */
  77
  78 static bool check_tcg_memory_orders_compatible(void)
  79 {
  80 #if defined(TCG_GUEST_DEFAULT_MO) && defined(TCG_TARGET_DEFAULT_MO)
  81     return (TCG_GUEST_DEFAULT_MO & ~TCG_TARGET_DEFAULT_MO) == 0;
  82 #else
  83     return false;
  84 #endif
  85 }
  86
  87 static bool default_mttcg_enabled(void)
  88 {
  89     if (icount_enabled() || TCG_OVERSIZED_GUEST) {
  90         return false;
  91     } else {
  92 #ifdef TARGET_SUPPORTS_MTTCG
  93         return check_tcg_memory_orders_compatible();
  94 #else
  95         return false;
  96 #endif
  97     }
  98 }
  99
 100 static void tcg_accel_instance_init(Object *obj)
 101 {
 102     TCGState *s = TCG_STATE(obj);
 103
 104     s->mttcg_enabled = default_mttcg_enabled();
 105
 106     /* If debugging enabled, default "auto on", otherwise off. */
 107 #if defined(CONFIG_DEBUG_TCG) && !defined(CONFIG_USER_ONLY)
 108     s->splitwx_enabled = -1;
 109 #else
 110     s->splitwx_enabled = 0;
 111 #endif
 112 }
 113
 114 bool mttcg_enabled;
 115 bool one_insn_per_tb;
 116
 117 static int tcg_init_machine(MachineState *ms)
 118 {
 119     TCGState *s = TCG_STATE(current_accel());
 120 #ifdef CONFIG_USER_ONLY
 121     unsigned max_cpus = 1;
 122 #else
 123     unsigned max_cpus = ms->smp.max_cpus;
 124 #endif
 125
 126     tcg_allowed = true;
 127     mttcg_enabled = s->mttcg_enabled;
 128
 129     page_init();
 130     tb_htable_init();
 131     tcg_init(s->tb_size * MiB, s->splitwx_enabled, max_cpus);
 132
 133 #if defined(CONFIG_SOFTMMU)
 134     /*
 135      * There's no guest base to take into account, so go ahead and
 136      * initialize the prologue now.
 137      */
 138     tcg_prologue_init(tcg_ctx);
 139 #endif
 140
 141     return 0;
 142 }
 143
 144 static char *tcg_get_thread(Object *obj, Error **errp)
 145 {
 146     TCGState *s = TCG_STATE(obj);
 147
 148     return g_strdup(s->mttcg_enabled ? "multi" : "single");
 149 }
 150
 151 static void tcg_set_thread(Object *obj, const char *value, Error **errp)
 152 {
 153     TCGState *s = TCG_STATE(obj);
 154
 155     if (strcmp(value, "multi") == 0) {
 156         if (TCG_OVERSIZED_GUEST) {
 157             error_setg(errp, "No MTTCG when guest word size > hosts");
 158         } else if (icount_enabled()) {
 159             error_setg(errp, "No MTTCG when icount is enabled");
 160         } else {
 161 #ifndef TARGET_SUPPORTS_MTTCG
 162             warn_report("Guest not yet converted to MTTCG - "
 163                         "you may get unexpected results");
 164 #endif
 165             if (!check_tcg_memory_orders_compatible()) {
 166                 warn_report("Guest expects a stronger memory ordering "
 167                             "than the host provides");
 168                 error_printf("This may cause strange/hard to debug errors\n");
 169             }
 170             s->mttcg_enabled = true;
 171         }
 172     } else if (strcmp(value, "single") == 0) {
 173         s->mttcg_enabled = false;
 174     } else {
 175         error_setg(errp, "Invalid 'thread' setting %s", value);
 176     }
 177 }
 178
 179 static void tcg_get_tb_size(Object *obj, Visitor *v,
 180                             const char *name, void *opaque,
 181                             Error **errp)
 182 {
 183     TCGState *s = TCG_STATE(obj);
 184     uint32_t value = s->tb_size;
 185
 186     visit_type_uint32(v, name, &value, errp);
 187 }
 188
 189 static void tcg_set_tb_size(Object *obj, Visitor *v,
 190                             const char *name, void *opaque,
 191                             Error **errp)
 192 {
 193     TCGState *s = TCG_STATE(obj);
 194     uint32_t value;
 195
 196     if (!visit_type_uint32(v, name, &value, errp)) {
 197         return;
 198     }
 199
 200     s->tb_size = value;
 201 }
 202
 203 static bool tcg_get_splitwx(Object *obj, Error **errp)
 204 {
 205     TCGState *s = TCG_STATE(obj);
 206     return s->splitwx_enabled;
 207 }
 208
 209 static void tcg_set_splitwx(Object *obj, bool value, Error **errp)
 210 {
 211     TCGState *s = TCG_STATE(obj);
 212     s->splitwx_enabled = value;
 213 }
 214
 215 static bool tcg_get_one_insn_per_tb(Object *obj, Error **errp)
 216 {
 217     TCGState *s = TCG_STATE(obj);
 218     return s->one_insn_per_tb;
 219 }
 220
 221 static void tcg_set_one_insn_per_tb(Object *obj, bool value, Error **errp)
 222 {
 223     TCGState *s = TCG_STATE(obj);
 224     s->one_insn_per_tb = value;
 225     /* Set the global also: this changes the behaviour */
 226     qatomic_set(&one_insn_per_tb, value);
 227 }
 228
 229 static int tcg_gdbstub_supported_sstep_flags(void)
 230 {
 231     /*
 232      * In replay mode all events will come from the log and can't be
 233      * suppressed otherwise we would break determinism. However as those
 234      * events are tied to the number of executed instructions we won't see
 235      * them occurring every time we single step.
 236      */
 237     if (replay_mode != REPLAY_MODE_NONE) {
 238         return SSTEP_ENABLE;
 239     } else {
 240         return SSTEP_ENABLE | SSTEP_NOIRQ | SSTEP_NOTIMER;
 241     }
 242 }
 243
 244 static void tcg_accel_class_init(ObjectClass *oc, void *data)
 245 {
 246     AccelClass *ac = ACCEL_CLASS(oc);
 247     ac->name = "tcg";
 248     ac->init_machine = tcg_init_machine;
 249     ac->allowed = &tcg_allowed;
 250     ac->gdbstub_supported_sstep_flags = tcg_gdbstub_supported_sstep_flags;
 251
 252     object_class_property_add_str(oc, "thread",
 253                                   tcg_get_thread,
 254                                   tcg_set_thread);
 255
 256     object_class_property_add(oc, "tb-size", "int",
 257         tcg_get_tb_size, tcg_set_tb_size,
 258         NULL, NULL);
 259     object_class_property_set_description(oc, "tb-size",
 260         "TCG translation block cache size");
 261
 262     object_class_property_add_bool(oc, "split-wx",
 263         tcg_get_splitwx, tcg_set_splitwx);
 264     object_class_property_set_description(oc, "split-wx",
 265         "Map jit pages into separate RW and RX regions");
 266
 267     object_class_property_add_bool(oc, "one-insn-per-tb",
 268                                    tcg_get_one_insn_per_tb,
 269                                    tcg_set_one_insn_per_tb);
 270     object_class_property_set_description(oc, "one-insn-per-tb",
 271         "Only put one guest insn in each translation block");
 272 }
 273
 274 static const TypeInfo tcg_accel_type = {
 275     .name = TYPE_TCG_ACCEL,
 276     .parent = TYPE_ACCEL,
 277     .instance_init = tcg_accel_instance_init,
 278     .class_init = tcg_accel_class_init,
 279     .instance_size = sizeof(TCGState),
 280 };
 281 module_obj(TYPE_TCG_ACCEL);
 282
 283 static void register_accel_types(void)
 284 {
 285     type_register_static(&tcg_accel_type);
 286 }
 287
 288 type_init(register_accel_types);