| Message ID | 20200717181623.2742758-4-richard.henderson@linaro.org |
|---|---|
| State | Accepted |
| Commit | ba3c35d9c4026361fd380b269dc6def9510b7166 |
| Headers | show |
| Series | tcg patch queue | expand |
On 17.07.2020 21:16, Richard Henderson wrote: > When single-stepping with a debugger attached to QEMU, and when an > interrupt is raised, the debugger misses the first instruction after > the interrupt. > > Tested-by: Luc Michel <luc.michel@greensocs.com> > Reviewed-by: Luc Michel <luc.michel@greensocs.com> > Buglink: https://bugs.launchpad.net/qemu/+bug/757702 > Message-Id: <20200717163029.2737546-1-richard.henderson@linaro.org> > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > --- > accel/tcg/cpu-exec.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c > index 6a3d3a3cfc..66d38f9d85 100644 > --- a/accel/tcg/cpu-exec.c > +++ b/accel/tcg/cpu-exec.c > @@ -588,7 +588,13 @@ static inline bool cpu_handle_interrupt(CPUState *cpu, > else { > if (cc->cpu_exec_interrupt(cpu, interrupt_request)) { > replay_interrupt(); > - cpu->exception_index = -1; > + /* > + * After processing the interrupt, ensure an EXCP_DEBUG is > + * raised when single-stepping so that GDB doesn't miss the > + * next instruction. > + */ > + cpu->exception_index = > + (cpu->singlestep_enabled ? EXCP_DEBUG : -1); > *last_tb = NULL; I just rebased my reverse debugging patches and noticed that this breaks the debugging in record/replay icount mode for i386. At some points "si" in remote gdb does nothing. This happens because of CPU_INTERRUPT_POLL. These are not real interrupts and converted into HW interrupt_request flags later. Therefore we shouldn't stop when there is CPU_INTERRUPT_POLL request. > } > /* The target hook may have updated the 'cpu->interrupt_request'; > Pavel Dovgalyuk
diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c index 6a3d3a3cfc..66d38f9d85 100644 --- a/accel/tcg/cpu-exec.c +++ b/accel/tcg/cpu-exec.c @@ -588,7 +588,13 @@ static inline bool cpu_handle_interrupt(CPUState *cpu, else { if (cc->cpu_exec_interrupt(cpu, interrupt_request)) { replay_interrupt(); - cpu->exception_index = -1; + /* + * After processing the interrupt, ensure an EXCP_DEBUG is + * raised when single-stepping so that GDB doesn't miss the + * next instruction. + */ + cpu->exception_index = + (cpu->singlestep_enabled ? EXCP_DEBUG : -1); *last_tb = NULL; } /* The target hook may have updated the 'cpu->interrupt_request';