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[Qemu-devel] [PULL 16/39] cpu: atomically modify cpu->exit_request
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PULL 16/39] cpu: atomically modify cpu->exit_request |
Date: |
Fri, 7 Oct 2016 18:57:40 +0200 |
From: Alex Bennée <address@hidden>
ThreadSanitizer picks up potential races although we already use
barriers to ensure things are in the correct order when processing exit
requests. For true C11 defined behaviour across threads we need to use
relaxed atomic_set/atomic_read semantics to reassure tsan.
Signed-off-by: Alex Bennée <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
cpu-exec.c | 8 ++++----
qom/cpu.c | 4 ++--
2 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/cpu-exec.c b/cpu-exec.c
index 8823d23..e114fcd 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -192,7 +192,7 @@ static inline tcg_target_ulong cpu_tb_exec(CPUState *cpu,
TranslationBlock *itb)
/* We were asked to stop executing TBs (probably a pending
* interrupt. We've now stopped, so clear the flag.
*/
- cpu->tcg_exit_req = 0;
+ atomic_set(&cpu->tcg_exit_req, 0);
}
return ret;
}
@@ -490,8 +490,8 @@ static inline void cpu_handle_interrupt(CPUState *cpu,
*last_tb = NULL;
}
}
- if (unlikely(cpu->exit_request || replay_has_interrupt())) {
- cpu->exit_request = 0;
+ if (unlikely(atomic_read(&cpu->exit_request) || replay_has_interrupt())) {
+ atomic_set(&cpu->exit_request, 0);
cpu->exception_index = EXCP_INTERRUPT;
cpu_loop_exit(cpu);
}
@@ -503,7 +503,7 @@ static inline void cpu_loop_exec_tb(CPUState *cpu,
TranslationBlock *tb,
{
uintptr_t ret;
- if (unlikely(cpu->exit_request)) {
+ if (unlikely(atomic_read(&cpu->exit_request))) {
return;
}
diff --git a/qom/cpu.c b/qom/cpu.c
index ef905da..e765bc0 100644
--- a/qom/cpu.c
+++ b/qom/cpu.c
@@ -120,10 +120,10 @@ void cpu_reset_interrupt(CPUState *cpu, int mask)
void cpu_exit(CPUState *cpu)
{
- cpu->exit_request = 1;
+ atomic_set(&cpu->exit_request, 1);
/* Ensure cpu_exec will see the exit request after TCG has exited. */
smp_wmb();
- cpu->tcg_exit_req = 1;
+ atomic_set(&cpu->tcg_exit_req, 1);
}
int cpu_write_elf32_qemunote(WriteCoreDumpFunction f, CPUState *cpu,
--
2.7.4
- [Qemu-devel] [PULL 06/39] intc/slavio_intctl: implement InterruptStatsProvider interface, (continued)
- [Qemu-devel] [PULL 06/39] intc/slavio_intctl: implement InterruptStatsProvider interface, Paolo Bonzini, 2016/10/07
- [Qemu-devel] [PULL 07/39] intc/lm32_pic: implement InterruptStatsProvider interface, Paolo Bonzini, 2016/10/07
- [Qemu-devel] [PULL 08/39] intc: make HMP 'info irq' and 'info pic' commands use InterruptStatsProvider interface, Paolo Bonzini, 2016/10/07
- [Qemu-devel] [PULL 09/39] intc: make HMP 'info irq' and 'info pic' commands available on all targets, Paolo Bonzini, 2016/10/07
- [Qemu-devel] [PULL 10/39] atomic.h: fix __SANITIZE_THREAD__ build, Paolo Bonzini, 2016/10/07
- [Qemu-devel] [PULL 11/39] atomic.h: comment on use of atomic_read/set, Paolo Bonzini, 2016/10/07
- [Qemu-devel] [PULL 12/39] tcg/optimize: move default return out of if statement, Paolo Bonzini, 2016/10/07
- [Qemu-devel] [PULL 13/39] seqlock: use atomic writes for the sequence, Paolo Bonzini, 2016/10/07
- [Qemu-devel] [PULL 14/39] qom/object: update class cache atomically, Paolo Bonzini, 2016/10/07
- [Qemu-devel] [PULL 15/39] qom/cpu: atomically clear the tb_jmp_cache, Paolo Bonzini, 2016/10/07
- [Qemu-devel] [PULL 16/39] cpu: atomically modify cpu->exit_request,
Paolo Bonzini <=
- [Qemu-devel] [PULL 17/39] util/qht: atomically set b->hashes, Paolo Bonzini, 2016/10/07
- [Qemu-devel] [PULL 18/39] linux-user/syscall: extend lock around cpu-list, Paolo Bonzini, 2016/10/07
- [Qemu-devel] [PULL 19/39] qga/command: use QEMU atomic primitives, Paolo Bonzini, 2016/10/07
- [Qemu-devel] [PULL 20/39] .travis.yml: add gcc sanitizer build, Paolo Bonzini, 2016/10/07
- [Qemu-devel] [PULL 22/39] char: use a fixed idx for child muxed chr, Paolo Bonzini, 2016/10/07
- [Qemu-devel] [PULL 21/39] i8259: give ISA device when registering ISA ioports, Paolo Bonzini, 2016/10/07
- [Qemu-devel] [PULL 23/39] char: update read handler in all cases, Paolo Bonzini, 2016/10/07
- [Qemu-devel] [PULL 25/39] qemu_kill_report: Report PID name too, Paolo Bonzini, 2016/10/07
- [Qemu-devel] [PULL 24/39] util: Introduce qemu_get_pid_name, Paolo Bonzini, 2016/10/07
- [Qemu-devel] [PULL 26/39] qemu-nbd: Shrink image size by specified offset, Paolo Bonzini, 2016/10/07