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[Qemu-devel] [PATCH 6/9] tcg: synchronize cpu->exit_request and cpu->tcg
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 6/9] tcg: synchronize cpu->exit_request and cpu->tcg_exit_req accesses |
Date: |
Wed, 26 Aug 2015 02:17:42 +0200 |
Signed-off-by: Paolo Bonzini <address@hidden>
---
cpu-exec.c | 6 +++++-
qom/cpu.c | 2 ++
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/cpu-exec.c b/cpu-exec.c
index 7fcc46f..2128bf1 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -542,8 +542,12 @@ int cpu_exec(CPUState *cpu)
* loop. Whatever requested the exit will also
* have set something else (eg exit_request or
* interrupt_request) which we will handle
- * next time around the loop.
+ * next time around the loop. But we need to
+ * ensure the tcg_exit_req read in generated code
+ * comes before the next read of cpu->exit_request
+ * or cpu->interrupt_request.
*/
+ smp_rmb();
next_tb = 0;
break;
case TB_EXIT_ICOUNT_EXPIRED:
diff --git a/qom/cpu.c b/qom/cpu.c
index 3e93223..3841f0d 100644
--- a/qom/cpu.c
+++ b/qom/cpu.c
@@ -114,6 +114,8 @@ void cpu_reset_interrupt(CPUState *cpu, int mask)
void cpu_exit(CPUState *cpu)
{
cpu->exit_request = 1;
+ /* Ensure cpu_exec will see the exit request after TCG has exited. */
+ smp_wmb();
cpu->tcg_exit_req = 1;
}
--
2.4.3
- [Qemu-devel] [PATCH v2 0/9] tcg: signal-free qemu_cpu_kick, Paolo Bonzini, 2015/08/25
- [Qemu-devel] [PATCH 3/9] tcg: introduce tcg_current_cpu, Paolo Bonzini, 2015/08/25
- [Qemu-devel] [PATCH 1/9] i8257: rewrite DMA_schedule to avoid hooking into the CPU loop, Paolo Bonzini, 2015/08/25
- [Qemu-devel] [PATCH 5/9] tcg: assign cpu->current_tb in a simpler place, Paolo Bonzini, 2015/08/25
- [Qemu-devel] [PATCH 2/9] i8257: remove cpu_request_exit irq, Paolo Bonzini, 2015/08/25
- [Qemu-devel] [PATCH 6/9] tcg: synchronize cpu->exit_request and cpu->tcg_exit_req accesses,
Paolo Bonzini <=
- [Qemu-devel] [PATCH 4/9] remove qemu/tls.h, Paolo Bonzini, 2015/08/25
- [Qemu-devel] [PATCH 7/9] tcg: synchronize exit_request and tcg_current_cpu accesses, Paolo Bonzini, 2015/08/25
- [Qemu-devel] [PATCH 8/9] use qemu_cpu_kick instead of cpu_exit or qemu_cpu_kick_thread, Paolo Bonzini, 2015/08/25
- [Qemu-devel] [PATCH 9/9] tcg: signal-free qemu_cpu_kick, Paolo Bonzini, 2015/08/25
- Re: [Qemu-devel] [PATCH v2 0/9] tcg: signal-free qemu_cpu_kick, Richard Henderson, 2015/08/28