From: Pavel Dovgalyuk <pavel.dovgalyuk@ispras.ru>
To: qemu-devel@nongnu.org
Cc: pbonzini@redhat.com, alex.bennee@linaro.org
Subject: Re: [PATCH] replay: fix watchpoint processing for reverse debugging
Date: Tue, 25 May 2021 09:40:24 +0300 [thread overview]
Message-ID: <fc75c7b5-e99c-f558-d24f-519041aa8d46@ispras.ru> (raw)
In-Reply-To: <162072430303.827403.7379783546934958566.stgit@pasha-ThinkPad-X280>
ping
On 11.05.2021 12:11, Pavel Dovgalyuk wrote:
> This patch enables reverse debugging with watchpoints.
> Reverse continue scans the execution to find the breakpoints
> and watchpoints that should fire. It uses helper function
> replay_breakpoint() for that. But this function needs to access
> icount, which can't be correct in the middle of TB.
> Therefore, in case of watchpoint, we have to retranslate the block
> to allow this access.
>
> Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
> ---
> softmmu/physmem.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/softmmu/physmem.c b/softmmu/physmem.c
> index 5232696571..2826d60cef 100644
> --- a/softmmu/physmem.c
> +++ b/softmmu/physmem.c
> @@ -904,6 +904,16 @@ void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len,
> if (watchpoint_address_matches(wp, addr, len)
> && (wp->flags & flags)) {
> if (replay_running_debug()) {
> + /*
> + * replay_breakpoint reads icount.
> + * Force recompile to succeed, because icount may
> + * be read only at the end of the block.
> + */
> + if (!cpu->can_do_io) {
> + /* Force execution of one insn next time. */
> + cpu->cflags_next_tb = 1 | CF_LAST_IO | curr_cflags(cpu);
> + cpu_loop_exit_restore(cpu, ra);
> + }
> /*
> * Don't process the watchpoints when we are
> * in a reverse debugging operation.
>
next prev parent reply other threads:[~2021-05-25 6:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-11 9:11 [PATCH] replay: fix watchpoint processing for reverse debugging Pavel Dovgalyuk
2021-05-25 6:40 ` Pavel Dovgalyuk [this message]
2021-05-25 23:11 ` Richard Henderson
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