diff options
| -rw-r--r-- | cpus-common.c | 33 | ||||
| -rw-r--r-- | include/qom/cpu.h | 14 |
2 files changed, 45 insertions, 2 deletions
diff --git a/cpus-common.c b/cpus-common.c index 429652c7fd..38b1d553fb 100644 --- a/cpus-common.c +++ b/cpus-common.c @@ -18,6 +18,7 @@ */ #include "qemu/osdep.h" +#include "qemu/main-loop.h" #include "exec/cpu-common.h" #include "qom/cpu.h" #include "sysemu/cpus.h" @@ -106,7 +107,7 @@ struct qemu_work_item { struct qemu_work_item *next; run_on_cpu_func func; void *data; - bool free, done; + bool free, exclusive, done; }; static void queue_work_on_cpu(CPUState *cpu, struct qemu_work_item *wi) @@ -139,6 +140,7 @@ void do_run_on_cpu(CPUState *cpu, run_on_cpu_func func, void *data, wi.data = data; wi.done = false; wi.free = false; + wi.exclusive = false; queue_work_on_cpu(cpu, &wi); while (!atomic_mb_read(&wi.done)) { @@ -229,6 +231,19 @@ void cpu_exec_end(CPUState *cpu) qemu_mutex_unlock(&qemu_cpu_list_lock); } +void async_safe_run_on_cpu(CPUState *cpu, run_on_cpu_func func, void *data) +{ + struct qemu_work_item *wi; + + wi = g_malloc0(sizeof(struct qemu_work_item)); + wi->func = func; + wi->data = data; + wi->free = true; + wi->exclusive = true; + + queue_work_on_cpu(cpu, wi); +} + void process_queued_cpu_work(CPUState *cpu) { struct qemu_work_item *wi; @@ -245,7 +260,21 @@ void process_queued_cpu_work(CPUState *cpu) cpu->queued_work_last = NULL; } qemu_mutex_unlock(&cpu->work_mutex); - wi->func(cpu, wi->data); + if (wi->exclusive) { + /* Running work items outside the BQL avoids the following deadlock: + * 1) start_exclusive() is called with the BQL taken while another + * CPU is running; 2) cpu_exec in the other CPU tries to takes the + * BQL, so it goes to sleep; start_exclusive() is sleeping too, so + * neither CPU can proceed. + */ + qemu_mutex_unlock_iothread(); + start_exclusive(); + wi->func(cpu, wi->data); + end_exclusive(); + qemu_mutex_lock_iothread(); + } else { + wi->func(cpu, wi->data); + } qemu_mutex_lock(&cpu->work_mutex); if (wi->free) { g_free(wi); diff --git a/include/qom/cpu.h b/include/qom/cpu.h index 934c07afbf..4092dd919b 100644 --- a/include/qom/cpu.h +++ b/include/qom/cpu.h @@ -656,6 +656,20 @@ void run_on_cpu(CPUState *cpu, run_on_cpu_func func, void *data); void async_run_on_cpu(CPUState *cpu, run_on_cpu_func func, void *data); /** + * async_safe_run_on_cpu: + * @cpu: The vCPU to run on. + * @func: The function to be executed. + * @data: Data to pass to the function. + * + * Schedules the function @func for execution on the vCPU @cpu asynchronously, + * while all other vCPUs are sleeping. + * + * Unlike run_on_cpu and async_run_on_cpu, the function is run outside the + * BQL. + */ +void async_safe_run_on_cpu(CPUState *cpu, run_on_cpu_func func, void *data); + +/** * qemu_get_cpu: * @index: The CPUState@cpu_index value of the CPU to obtain. * |