[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PULL 14/43] tcg: synchronize exit_request and tcg_current_
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PULL 14/43] tcg: synchronize exit_request and tcg_current_cpu accesses |
Date: |
Wed, 9 Sep 2015 15:49:44 +0200 |
Synchronize the remaining pair of accesses in cpu_signal. These should
be necessary on Windows as well, at least in theory. Probably
SuspendProcess and ResumeProcess introduce some implicit memory
barrier.
Reviewed-by: Richard Henderson <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
cpu-exec.c | 2 +-
cpus.c | 14 ++++++++++----
2 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/cpu-exec.c b/cpu-exec.c
index e24c640..ef9d745 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -372,7 +372,7 @@ int cpu_exec(CPUState *cpu)
atomic_mb_set(&tcg_current_cpu, cpu);
rcu_read_lock();
- if (unlikely(exit_request)) {
+ if (unlikely(atomic_mb_read(&exit_request))) {
cpu->exit_request = 1;
}
diff --git a/cpus.c b/cpus.c
index 6cebb7a..dd2fc29 100644
--- a/cpus.c
+++ b/cpus.c
@@ -663,11 +663,15 @@ static void cpu_handle_guest_debug(CPUState *cpu)
static void cpu_signal(int sig)
{
- CPUState *cpu = atomic_mb_read(&tcg_current_cpu);
+ CPUState *cpu;
+ /* Ensure whatever caused the exit has reached the CPU threads before
+ * writing exit_request.
+ */
+ atomic_mb_set(&exit_request, 1);
+ cpu = atomic_mb_read(&tcg_current_cpu);
if (cpu) {
cpu_exit(cpu);
}
- exit_request = 1;
}
#ifdef CONFIG_LINUX
@@ -1063,7 +1067,7 @@ static void *qemu_tcg_cpu_thread_fn(void *arg)
}
/* process any pending work */
- exit_request = 1;
+ atomic_mb_set(&exit_request, 1);
while (1) {
tcg_exec_all();
@@ -1441,7 +1445,9 @@ static void tcg_exec_all(void)
break;
}
}
- exit_request = 0;
+
+ /* Pairs with smp_wmb in qemu_cpu_kick. */
+ atomic_mb_set(&exit_request, 0);
}
void list_cpus(FILE *f, fprintf_function cpu_fprintf, const char *optarg)
--
2.4.3
- [Qemu-devel] [PULL 02/43] seqlock: add missing 'inline' to seqlock_read_retry, (continued)
- [Qemu-devel] [PULL 02/43] seqlock: add missing 'inline' to seqlock_read_retry, Paolo Bonzini, 2015/09/09
- [Qemu-devel] [PULL 01/43] qemu-thread: handle spurious futex_wait wakeups, Paolo Bonzini, 2015/09/09
- [Qemu-devel] [PULL 03/43] seqlock: read sequence number atomically, Paolo Bonzini, 2015/09/09
- [Qemu-devel] [PULL 04/43] cpus.c: qemu_mutex_lock_iothread fix race condition at cpu thread init, Paolo Bonzini, 2015/09/09
- [Qemu-devel] [PULL 05/43] iohandler: Use aio API, Paolo Bonzini, 2015/09/09
- [Qemu-devel] [PULL 08/43] i8257: rewrite DMA_schedule to avoid hooking into the CPU loop, Paolo Bonzini, 2015/09/09
- [Qemu-devel] [PULL 06/43] block/iscsi: validate block size returned from target, Paolo Bonzini, 2015/09/09
- [Qemu-devel] [PULL 10/43] tcg: introduce tcg_current_cpu, Paolo Bonzini, 2015/09/09
- [Qemu-devel] [PULL 07/43] Added generic panic handler qemu_system_guest_panicked(), Paolo Bonzini, 2015/09/09
- [Qemu-devel] [PULL 09/43] i8257: remove cpu_request_exit irq, Paolo Bonzini, 2015/09/09
- [Qemu-devel] [PULL 14/43] tcg: synchronize exit_request and tcg_current_cpu accesses,
Paolo Bonzini <=
- [Qemu-devel] [PULL 15/43] use qemu_cpu_kick instead of cpu_exit or qemu_cpu_kick_thread, Paolo Bonzini, 2015/09/09
- [Qemu-devel] [PULL 11/43] remove qemu/tls.h, Paolo Bonzini, 2015/09/09
- [Qemu-devel] [PULL 13/43] tcg: synchronize cpu->exit_request and cpu->tcg_exit_req accesses, Paolo Bonzini, 2015/09/09
- [Qemu-devel] [PULL 16/43] tcg: signal-free qemu_cpu_kick, Paolo Bonzini, 2015/09/09
- [Qemu-devel] [PULL 12/43] tcg: assign cpu->current_tb in a simpler place, Paolo Bonzini, 2015/09/09
- [Qemu-devel] [PULL 18/43] Makefile.target: include top level build dir in vpath, Paolo Bonzini, 2015/09/09
- [Qemu-devel] [PULL 17/43] Move RAMBlock and ram_list to ram_addr.h, Paolo Bonzini, 2015/09/09
- [Qemu-devel] [PULL 22/43] translate-all: remove obsolete comment about l1_map, Paolo Bonzini, 2015/09/09
- [Qemu-devel] [PULL 20/43] rcu: fix comment with s/rcu_gp_lock/rcu_registry_lock/, Paolo Bonzini, 2015/09/09
- [Qemu-devel] [PULL 21/43] linux-user: call rcu_(un)register_thread on pthread_(exit|create), Paolo Bonzini, 2015/09/09