From: "Philippe Mathieu-Daudé" <philmd@redhat.com>
To: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: [PULL 34/37] gdbstub: add reverse continue support in replay mode
Date: Fri, 30 Oct 2020 16:15:09 +0100 [thread overview]
Message-ID: <CAP+75-XRQ4uqhtn12kPe9gOrH269rOpW3SowHEj_KqkX=zAeoQ@mail.gmail.com> (raw)
In-Reply-To: <20201006072947.487729-35-pbonzini@redhat.com>
Hi Pavel,
On Tue, Oct 6, 2020 at 9:41 AM Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> From: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
>
> This patch adds support of the reverse continue operation for gdbstub.
> Reverse continue finds the last breakpoint that would happen in normal
> execution from the beginning to the current moment.
> Implementation of the reverse continue replays the execution twice:
> to find the breakpoints that were hit and to seek to the last breakpoint.
> Reverse continue loads the previous snapshot and tries to find the breakpoint
> since that moment. If there are no such breakpoints, it proceeds to
> the earlier snapshot, and so on. When no breakpoints or watchpoints were
> hit at all, execution stops at the beginning of the replay log.
>
> Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
> Message-Id: <160174522930.12451.6994758004725016836.stgit@pasha-ThinkPad-X280>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> exec.c | 1 +
> gdbstub.c | 10 +++++-
> include/sysemu/replay.h | 8 +++++
> replay/replay-debugging.c | 72 +++++++++++++++++++++++++++++++++++++++
> softmmu/cpus.c | 5 +++
> stubs/replay.c | 5 +++
> 6 files changed, 100 insertions(+), 1 deletion(-)
...
> +static void replay_continue_stop(void *opaque)
> +{
> + Error *err = NULL;
> + if (replay_last_breakpoint != -1LL) {
> + replay_seek(replay_last_breakpoint, replay_stop_vm_debug, &err);
> + if (err) {
> + error_free(err);
> + replay_continue_end();
> + }
> + return;
> + }
> + /*
> + * No breakpoints since the last snapshot.
> + * Find previous snapshot and try again.
> + */
> + if (replay_last_snapshot != 0) {
> + replay_seek(replay_last_snapshot - 1, replay_continue_stop, &err);
> + if (err) {
> + error_free(err);
> + replay_continue_end();
> + }
> + replay_last_snapshot = replay_get_current_icount();
> + return;
> + } else {
> + /* Seek to the very first step */
> + replay_seek(0, replay_stop_vm_debug, &err);
> + if (err) {
> + error_free(err);
> + replay_continue_end();
> + }
> + return;
> + }
Coverity (CID 1433220) reports this is dead code:
> + replay_continue_end();
> +}
> +
next prev parent reply other threads:[~2020-10-30 15:18 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-06 7:29 [PULL 00/37] Build system + accel + record/replay patches for 2020-10-06 Paolo Bonzini
2020-10-06 7:29 ` [PULL 01/37] cpu-timers, icount: new modules Paolo Bonzini
2020-10-06 7:29 ` [PULL 02/37] icount: rename functions to be consistent with the module name Paolo Bonzini
2020-10-06 7:29 ` [PULL 03/37] cpus: prepare new CpusAccel cpu accelerator interface Paolo Bonzini
2020-10-06 7:29 ` [PULL 04/37] cpus: extract out TCG-specific code to accel/tcg Paolo Bonzini
2020-10-06 7:29 ` [PULL 05/37] cpus: extract out qtest-specific code to accel/qtest Paolo Bonzini
2020-10-06 7:29 ` [PULL 06/37] cpus: extract out kvm-specific code to accel/kvm Paolo Bonzini
2020-10-06 7:29 ` [PULL 07/37] cpus: extract out hax-specific code to target/i386/ Paolo Bonzini
2020-10-16 6:48 ` Volker Rümelin
2020-10-16 8:00 ` Claudio Fontana
2020-10-17 7:17 ` Volker Rümelin
2020-10-06 7:29 ` [PULL 08/37] cpus: extract out whpx-specific " Paolo Bonzini
2020-10-06 7:29 ` [PULL 09/37] cpus: extract out hvf-specific code to target/i386/hvf/ Paolo Bonzini
2020-10-06 7:29 ` [PULL 10/37] cpus: cleanup now unneeded includes Paolo Bonzini
2020-10-06 7:29 ` [PULL 11/37] cpus: remove checks for non-NULL cpus_accel Paolo Bonzini
2020-10-06 7:29 ` [PULL 12/37] cpus: add handle_interrupt to the CpusAccel interface Paolo Bonzini
2020-10-06 7:29 ` [PULL 13/37] hvf: remove hvf specific functions from global includes Paolo Bonzini
2020-10-06 7:29 ` [PULL 14/37] whpx: remove whpx " Paolo Bonzini
2020-10-06 7:29 ` [PULL 15/37] hax: remove hax " Paolo Bonzini
2020-10-06 7:29 ` [PULL 16/37] kvm: remove kvm " Paolo Bonzini
2020-10-06 7:29 ` [PULL 17/37] kvm: kvm_init_vcpu take Error pointer Paolo Bonzini
2020-10-06 7:29 ` [PULL 18/37] accel/tcg: use current_machine as it is always set for softmmu Paolo Bonzini
2020-10-06 7:29 ` [PULL 19/37] slirp: Convert Makefile bits to meson bits Paolo Bonzini
2020-10-06 7:29 ` [PULL 20/37] dtc: " Paolo Bonzini
2020-10-06 7:29 ` [PULL 21/37] configure: do not clobber environment CFLAGS/CXXFLAGS/LDFLAGS Paolo Bonzini
2020-10-06 7:29 ` [PULL 22/37] configure: consistently pass CFLAGS/CXXFLAGS/LDFLAGS to meson Paolo Bonzini
2020-10-06 7:29 ` [PULL 23/37] configure: don't enable ASLR for --enable-debug Windows builds Paolo Bonzini
2020-10-06 7:29 ` [PULL 24/37] replay: don't record interrupt poll Paolo Bonzini
2020-10-06 7:29 ` [PULL 25/37] replay: provide an accessor for rr filename Paolo Bonzini
2020-10-06 7:29 ` [PULL 26/37] qcow2: introduce icount field for snapshots Paolo Bonzini
2020-10-06 7:29 ` [PULL 27/37] migration: " Paolo Bonzini
2020-10-06 13:44 ` Eric Blake
2020-10-06 7:29 ` [PULL 28/37] qapi: introduce replay.json for record/replay-related stuff Paolo Bonzini
2020-10-06 7:29 ` [PULL 29/37] replay: introduce info hmp/qmp command Paolo Bonzini
2020-10-06 7:29 ` [PULL 30/37] replay: introduce breakpoint at the specified step Paolo Bonzini
2020-10-06 7:29 ` [PULL 31/37] replay: implement replay-seek command Paolo Bonzini
2020-10-06 7:29 ` [PULL 32/37] replay: flush rr queue before loading the vmstate Paolo Bonzini
2020-10-06 7:29 ` [PULL 33/37] gdbstub: add reverse step support in replay mode Paolo Bonzini
2020-10-06 7:29 ` [PULL 34/37] gdbstub: add reverse continue " Paolo Bonzini
2020-10-30 15:15 ` Philippe Mathieu-Daudé [this message]
2020-10-06 7:29 ` [PULL 35/37] replay: describe reverse debugging in docs/replay.txt Paolo Bonzini
2020-10-06 7:29 ` [PULL 36/37] replay: create temporary snapshot at debugger connection Paolo Bonzini
2020-10-06 7:29 ` [PULL 37/37] tests/acceptance: add reverse debugging test Paolo Bonzini
2020-10-06 20:13 ` [PULL 00/37] Build system + accel + record/replay patches for 2020-10-06 Peter Maydell
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAP+75-XRQ4uqhtn12kPe9gOrH269rOpW3SowHEj_KqkX=zAeoQ@mail.gmail.com' \
--to=philmd@redhat.com \
--cc=Pavel.Dovgalyuk@ispras.ru \
--cc=pbonzini@redhat.com \
--cc=qemu-devel@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).