[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH 2/3] replay: check icount in cpu exec loop
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 2/3] replay: check icount in cpu exec loop |
Date: |
Tue, 21 Feb 2017 13:46:37 +0100 |
From: Pavel Dovgalyuk <address@hidden>
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.
Because cpu_loop_exec_tb does not longjmp anymore after exhausting the
icount decrementer, it can use the align_clocks call in cpu_exec. Remove
the one in cpu_loop_exec_tb, as well as the SyncClocks *sc argument.
Signed-off-by: Pavel Dovgalyuk <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
cpu-exec.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
diff --git a/cpu-exec.c b/cpu-exec.c
index 18e1973..bf126dd 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -517,7 +517,10 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
*last_tb = NULL;
}
}
- if (unlikely(atomic_read(&cpu->exit_request) || replay_has_interrupt())) {
+
+ /* Finally, check if we need to exit to the main loop. */
+ if (unlikely(atomic_read(&cpu->exit_request)
+ || (use_icount && cpu->icount_decr.u16.low + cpu->icount_extra == 0)))
{
atomic_set(&cpu->exit_request, 0);
cpu->exception_index = EXCP_INTERRUPT;
return true;
@@ -527,8 +530,7 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
}
static inline void cpu_loop_exec_tb(CPUState *cpu, TranslationBlock *tb,
- TranslationBlock **last_tb, int *tb_exit,
- SyncClocks *sc)
+ TranslationBlock **last_tb, int *tb_exit)
{
uintptr_t ret;
int32_t insns_left;
@@ -578,10 +580,7 @@ static inline void cpu_loop_exec_tb(CPUState *cpu,
TranslationBlock *tb,
*/
if (insns_left > 0) {
cpu_exec_nocache(cpu, insns_left, tb, false);
- align_clocks(sc, cpu);
}
- cpu->exception_index = EXCP_INTERRUPT;
- cpu_loop_exit(cpu);
}
}
@@ -641,7 +640,7 @@ int cpu_exec(CPUState *cpu)
while (!cpu_handle_interrupt(cpu, &last_tb)) {
TranslationBlock *tb = tb_find(cpu, last_tb, tb_exit);
- cpu_loop_exec_tb(cpu, tb, &last_tb, &tb_exit, &sc);
+ cpu_loop_exec_tb(cpu, tb, &last_tb, &tb_exit);
/* Try to align the host and virtual clocks
if the guest is in advance */
align_clocks(&sc, cpu);
--
2.9.3