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[Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire
From: |
Pavel Dovgalyuk |
Subject: |
[Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire |
Date: |
Thu, 26 Jan 2017 15:34:23 +0300 |
User-agent: |
StGit/0.16 |
This patch adds check to break cpu loop when icount expires without
setting the TB_EXIT_ICOUNT_EXPIRED flag. It happens when there is no
available translated blocks and all instructions were executed.
In icount replay mode unnecessary tb_find will be called (which may
cause an exception) and execution will be non-deterministic.
v8: refactored loop exit code and moved it to separate function
Signed-off-by: Pavel Dovgalyuk <address@hidden>
---
cpu-exec.c | 24 +++++++++++++++++++-----
1 file changed, 19 insertions(+), 5 deletions(-)
diff --git a/cpu-exec.c b/cpu-exec.c
index fa08c73..f9b8ec8 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -523,9 +523,25 @@ static inline void cpu_handle_interrupt(CPUState *cpu,
*last_tb = NULL;
}
}
- if (unlikely(atomic_read(&cpu->exit_request) || replay_has_interrupt())) {
+}
+
+
+static void cpu_check_loop_exit(CPUState *cpu)
+{
+ if (unlikely(atomic_read(&cpu->exit_request)
+ /* icount has expired, we need to break the execution loop.
+ This check is needed before tb_find to make execution
+ deterministic - tb_find may cause an exception
+ while translating the code from non-mapped page. */
+ || (use_icount && ((cpu->icount_extra == 0
+ && cpu->icount_decr.u16.low == 0)
+ || (int32_t)cpu->icount_decr.u32 < 0)))) {
atomic_set(&cpu->exit_request, 0);
- cpu->exception_index = EXCP_INTERRUPT;
+ /* If there is an exception that wasn't replayed yet,
+ don't change exception_index. */
+ if (cpu->exception_index == -1) {
+ cpu->exception_index = EXCP_INTERRUPT;
+ }
cpu_loop_exit(cpu);
}
}
@@ -578,9 +594,6 @@ static inline void cpu_loop_exec_tb(CPUState *cpu,
TranslationBlock *tb,
cpu_exec_nocache(cpu, insns_left, *last_tb, false);
align_clocks(sc, cpu);
}
- cpu->exception_index = EXCP_INTERRUPT;
- *last_tb = NULL;
- cpu_loop_exit(cpu);
}
break;
#endif
@@ -634,6 +647,7 @@ int cpu_exec(CPUState *cpu)
for(;;) {
cpu_handle_interrupt(cpu, &last_tb);
+ cpu_check_loop_exit(cpu);
tb = tb_find(cpu, last_tb, tb_exit);
cpu_loop_exec_tb(cpu, tb, &last_tb, &tb_exit, &sc);
/* Try to align the host and virtual clocks
- [Qemu-devel] [PATCH v8 0/9] replay additions, Pavel Dovgalyuk, 2017/01/26
- [Qemu-devel] [PATCH v8 1/9] replay: exception replay fix, Pavel Dovgalyuk, 2017/01/26
- [Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire,
Pavel Dovgalyuk <=
- Re: [Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire, Paolo Bonzini, 2017/01/26
- Re: [Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire, Pavel Dovgalyuk, 2017/01/26
- Re: [Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire, Paolo Bonzini, 2017/01/26
- Re: [Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire, Pavel Dovgalyuk, 2017/01/26
- Re: [Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire, Paolo Bonzini, 2017/01/26
- Re: [Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire, Pavel Dovgalyuk, 2017/01/27
- Re: [Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire, Paolo Bonzini, 2017/01/27
[Qemu-devel] [PATCH v8 3/9] apic: save apic_delivered flag, Pavel Dovgalyuk, 2017/01/26