| 1 | /* |
| 2 | * QEMU TCG Multi Threaded vCPUs implementation |
| 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 "exec/cpu-common.h" |
| 28 | #include "system/tcg.h" |
| 29 | #include "system/replay.h" |
| 30 | #include "exec/icount.h" |
| 31 | #include "qemu/main-loop.h" |
| 32 | #include "qemu/notify.h" |
| 33 | #include "qemu/guest-random.h" |
| 34 | #include "hw/core/boards.h" |
| 35 | #include "accel/tcg/cpu-loop.h" |
| 36 | #include "tcg/startup.h" |
| 37 | #include "tcg-accel-ops.h" |
| 38 | #include "tcg-accel-ops-mttcg.h" |
| 39 | |
| 40 | typedef struct MttcgForceRcuNotifier { |
| 41 | Notifier notifier; |
| 42 | CPUState *cpu; |
| 43 | } MttcgForceRcuNotifier; |
| 44 | |
| 45 | static void do_nothing(CPUState *cpu, run_on_cpu_data d) |
| 46 | { |
| 47 | } |
| 48 | |
| 49 | static void mttcg_force_rcu(Notifier *notify, void *data) |
| 50 | { |
| 51 | CPUState *cpu = container_of(notify, MttcgForceRcuNotifier, notifier)->cpu; |
| 52 | |
| 53 | /* |
| 54 | * Called with rcu_registry_lock held, using async_run_on_cpu() ensures |
| 55 | * that there are no deadlocks. |
| 56 | */ |
| 57 | async_run_on_cpu(cpu, do_nothing, RUN_ON_CPU_NULL); |
| 58 | } |
| 59 | |
| 60 | /* |
| 61 | * In the multi-threaded case each vCPU has its own thread. The TLS |
| 62 | * variable current_cpu can be used deep in the code to find the |
| 63 | * current CPUState for a given thread. |
| 64 | */ |
| 65 | |
| 66 | static void *mttcg_cpu_thread_fn(void *arg) |
| 67 | { |
| 68 | MttcgForceRcuNotifier force_rcu; |
| 69 | CPUState *cpu = arg; |
| 70 | |
| 71 | assert(tcg_enabled()); |
| 72 | g_assert(!icount_enabled()); |
| 73 | |
| 74 | rcu_register_thread(); |
| 75 | force_rcu.notifier.notify = mttcg_force_rcu; |
| 76 | force_rcu.cpu = cpu; |
| 77 | rcu_add_force_rcu_notifier(&force_rcu.notifier); |
| 78 | tcg_register_thread(); |
| 79 | |
| 80 | bql_lock(); |
| 81 | qemu_thread_get_self(cpu->thread); |
| 82 | |
| 83 | cpu->thread_id = qemu_get_thread_id(); |
| 84 | cpu->neg.can_do_io = true; |
| 85 | current_cpu = cpu; |
| 86 | cpu_thread_signal_created(cpu); |
| 87 | qemu_guest_random_seed_thread_part2(cpu->random_seed); |
| 88 | |
| 89 | do { |
| 90 | qemu_process_cpu_events(cpu); |
| 91 | |
| 92 | if (cpu_can_run(cpu)) { |
| 93 | int r; |
| 94 | bql_unlock(); |
| 95 | r = tcg_cpu_exec(cpu); |
| 96 | bql_lock(); |
| 97 | switch (r) { |
| 98 | case EXCP_DEBUG: |
| 99 | cpu_handle_guest_debug(cpu); |
| 100 | break; |
| 101 | case EXCP_HALTED: |
| 102 | /* |
| 103 | * Usually cpu->halted is set, but may have already been |
| 104 | * reset by another thread by the time we arrive here. |
| 105 | */ |
| 106 | break; |
| 107 | case EXCP_ATOMIC: |
| 108 | bql_unlock(); |
| 109 | cpu_exec_step_atomic(cpu); |
| 110 | bql_lock(); |
| 111 | default: |
| 112 | /* Ignore everything else? */ |
| 113 | break; |
| 114 | } |
| 115 | } |
| 116 | } while (!cpu->unplug || cpu_can_run(cpu)); |
| 117 | |
| 118 | tcg_cpu_destroy(cpu); |
| 119 | bql_unlock(); |
| 120 | rcu_remove_force_rcu_notifier(&force_rcu.notifier); |
| 121 | rcu_unregister_thread(); |
| 122 | return NULL; |
| 123 | } |
| 124 | |
| 125 | void mttcg_start_vcpu_thread(CPUState *cpu) |
| 126 | { |
| 127 | char thread_name[VCPU_THREAD_NAME_SIZE]; |
| 128 | |
| 129 | g_assert(tcg_enabled()); |
| 130 | tcg_cpu_init_cflags(cpu, current_machine->smp.max_cpus > 1); |
| 131 | |
| 132 | /* create a thread per vCPU with TCG (MTTCG) */ |
| 133 | snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "CPU %d/TCG", |
| 134 | cpu->cpu_index); |
| 135 | |
| 136 | qemu_thread_create(cpu->thread, thread_name, mttcg_cpu_thread_fn, |
| 137 | cpu, QEMU_THREAD_JOINABLE); |
| 138 | } |