Re: [PATCH v4 3/3] replay: do not build if TCG is not available

[Pavel Dovgalyuk <pavel.dovgalyuk@ispras.ru>]

On 13.10.2020 22:21, Claudio Fontana wrote:
> this fixes non-TCG builds broken recently by replay reverse debugging.
> 
> stub the needed functions in stub/, including errors for hmp and qmp.
> This includes duplicating some code in replay/, and puts the logic
> for non-replay related events in the replay/ module (+ the stubs),
> so this should be revisited in the future.
> 
> Surprisingly, only _one_ qtest was affected by this, ide-test.c, which
> resulted in a buzz as the bh events were never delivered, and the bh
> never executed.
> 
> Many other subsystems _should_ have been affected.
> 
> This fixes the immediate issue, however a better way to group replay
> functionality to TCG-only code could be developed in the long term.
> 
> Signed-off-by: Claudio Fontana <cfontana@suse.de>
> ---
>   block/meson.build          |  3 +-
>   migration/savevm.c         | 11 +++--
>   net/meson.build            |  3 +-
>   replay/meson.build         |  2 +-
>   replay/replay-input.c      |  4 +-
>   stubs/meson.build          |  1 -
>   stubs/replay-user.c        |  9 ----
>   stubs/replay.c             | 98 ++++++++++++++++++++++++++++++++++++++
>   tests/ptimer-test-stubs.c  |  5 --
>   tests/qtest/qmp-cmd-test.c |  3 ++
>   ui/input.c                 | 12 ++++-
>   11 files changed, 125 insertions(+), 26 deletions(-)
>   delete mode 100644 stubs/replay-user.c
> 
> diff --git a/block/meson.build b/block/meson.build
> index 78e8b25232..01fe6f84d2 100644
> --- a/block/meson.build
> +++ b/block/meson.build
> @@ -7,7 +7,6 @@ block_ss.add(files(
>     'backup-top.c',
>     'blkdebug.c',
>     'blklogwrites.c',
> -  'blkreplay.c',
>     'blkverify.c',
>     'block-backend.c',
>     'block-copy.c',
> @@ -42,6 +41,8 @@ block_ss.add(files(
>     'write-threshold.c',
>   ), zstd, zlib)
>   
> +block_ss.add(when: 'CONFIG_TCG', if_true: files('blkreplay.c'))
> +
>   block_ss.add(when: 'CONFIG_QCOW1', if_true: files('qcow.c'))
>   block_ss.add(when: 'CONFIG_VDI', if_true: files('vdi.c'))
>   block_ss.add(when: 'CONFIG_CLOOP', if_true: files('cloop.c'))
> diff --git a/migration/savevm.c b/migration/savevm.c
> index d2e141f7b1..d9181ca520 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -63,6 +63,7 @@
>   #include "migration/colo.h"
>   #include "qemu/bitmap.h"
>   #include "net/announce.h"
> +#include "sysemu/tcg.h"
>   
>   const unsigned int postcopy_ram_discard_version = 0;
>   
> @@ -2674,10 +2675,12 @@ int save_snapshot(const char *name, Error **errp)
>           return ret;
>       }
>   
> -    if (!replay_can_snapshot()) {
> -        error_setg(errp, "Record/replay does not allow making snapshot "
> -                   "right now. Try once more later.");
> -        return ret;
> +    if (tcg_enabled()) {
> +        if (!replay_can_snapshot()) {
> +            error_setg(errp, "Record/replay does not allow making snapshot "
> +                       "right now. Try once more later.");
> +            return ret;
> +        }
>       }
>   
>       if (!bdrv_all_can_snapshot(&bs)) {
> diff --git a/net/meson.build b/net/meson.build
> index 1c7e3a3cb9..1076b0a7ab 100644
> --- a/net/meson.build
> +++ b/net/meson.build
> @@ -7,7 +7,6 @@ softmmu_ss.add(files(
>     'eth.c',
>     'filter-buffer.c',
>     'filter-mirror.c',
> -  'filter-replay.c',
>     'filter-rewriter.c',
>     'filter.c',
>     'hub.c',
> @@ -17,6 +16,8 @@ softmmu_ss.add(files(
>     'util.c',
>   ))
>   
> +softmmu_ss.add(when: 'CONFIG_TCG', if_true: files('filter-replay.c'))
> +
>   softmmu_ss.add(when: 'CONFIG_L2TPV3', if_true: files('l2tpv3.c'))
>   softmmu_ss.add(when: slirp, if_true: files('slirp.c'))
>   softmmu_ss.add(when: ['CONFIG_VDE', vde], if_true: files('vde.c'))
> diff --git a/replay/meson.build b/replay/meson.build
> index f91163fb1e..cb3207740a 100644
> --- a/replay/meson.build
> +++ b/replay/meson.build
> @@ -1,4 +1,4 @@
> -softmmu_ss.add(files(
> +softmmu_ss.add(when: 'CONFIG_TCG', if_true: files(
>     'replay.c',
>     'replay-internal.c',
>     'replay-events.c',
> diff --git a/replay/replay-input.c b/replay/replay-input.c
> index 1147e3d34e..5d1fd92e79 100644
> --- a/replay/replay-input.c
> +++ b/replay/replay-input.c
> @@ -124,7 +124,7 @@ void replay_input_event(QemuConsole *src, InputEvent *evt)
>       } else if (replay_mode == REPLAY_MODE_RECORD) {
>           replay_add_input_event(QAPI_CLONE(InputEvent, evt));
>       } else {
> -        qemu_input_event_send_impl(src, evt);
> +        g_assert_not_reached();
>       }
>   }
>   
> @@ -135,6 +135,6 @@ void replay_input_sync_event(void)
>       } else if (replay_mode == REPLAY_MODE_RECORD) {
>           replay_add_input_sync_event();
>       } else {
> -        qemu_input_event_sync_impl();
> +        g_assert_not_reached();
>       }
>   }
> diff --git a/stubs/meson.build b/stubs/meson.build
> index 67f2a8c069..bbd2230d69 100644
> --- a/stubs/meson.build
> +++ b/stubs/meson.build
> @@ -32,7 +32,6 @@ stub_ss.add(files('qtest.c'))
>   stub_ss.add(files('ram-block.c'))
>   stub_ss.add(files('ramfb.c'))
>   stub_ss.add(files('replay.c'))
> -stub_ss.add(files('replay-user.c'))
>   stub_ss.add(files('runstate-check.c'))
>   stub_ss.add(files('set-fd-handler.c'))
>   stub_ss.add(files('sysbus.c'))
> diff --git a/stubs/replay-user.c b/stubs/replay-user.c
> deleted file mode 100644
> index 2ad9e27203..0000000000
> --- a/stubs/replay-user.c
> +++ /dev/null
> @@ -1,9 +0,0 @@
> -#include "qemu/osdep.h"
> -#include "sysemu/replay.h"
> -#include "sysemu/sysemu.h"
> -
> -void replay_bh_schedule_oneshot_event(AioContext *ctx,
> -    QEMUBHFunc *cb, void *opaque)
> -{
> -    aio_bh_schedule_oneshot(ctx, cb, opaque);
> -}
> diff --git a/stubs/replay.c b/stubs/replay.c
> index 45ebe77fb9..34b7975b2d 100644
> --- a/stubs/replay.c
> +++ b/stubs/replay.c
> @@ -103,3 +103,101 @@ bool replay_reverse_continue(void)
>   {
>       return false;
>   }
> +
> +void replay_input_event(QemuConsole *src, InputEvent *evt)
> +{
> +}
> +void replay_input_sync_event(void)
> +{
> +}
> +void replay_bh_schedule_event(QEMUBH *bh)
> +{
> +    qemu_bh_schedule(bh);
> +}
> +void replay_bh_schedule_oneshot_event(AioContext *ctx,
> +     QEMUBHFunc *cb, void *opaque)
> +{
> +    aio_bh_schedule_oneshot(ctx, cb, opaque);
> +}
> +void replay_add_blocker(Error *reason)
> +{
> +}
> +void replay_audio_in(size_t *recorded, void *samples, size_t *wpos, size_t size)
> +{
> +}
> +void replay_audio_out(size_t *played)
> +{
> +}
> +void replay_breakpoint(void)
> +{
> +}
> +bool replay_can_snapshot(void)
> +{
> +    return false;
> +}

Shouldn't this one return true to enable snapshotting?


> +void replay_configure(struct QemuOpts *opts)
> +{
> +}
> +void replay_flush_events(void)
> +{
> +}
> +void replay_gdb_attached(void)
> +{
> +}
> +bool replay_running_debug(void)
> +{
> +    return false;
> +}
> +void replay_shutdown_request(ShutdownCause cause)
> +{
> +}
> +void replay_start(void)
> +{
> +}
> +void replay_vmstate_init(void)
> +{
> +}
> +
> +#include "monitor/monitor.h"
> +#include "monitor/hmp.h"
> +#include "qapi/qapi-commands-replay.h"
> +#include "qapi/error.h"
> +#include "qemu/error-report.h"
> +
> +void hmp_info_replay(Monitor *mon, const QDict *qdict)
> +{
> +    error_report("replay support not available");
> +}
> +void hmp_replay_break(Monitor *mon, const QDict *qdict)
> +{
> +    error_report("replay support not available");
> +}
> +void hmp_replay_delete_break(Monitor *mon, const QDict *qdict)
> +{
> +    error_report("replay support not available");
> +}
> +void hmp_replay_seek(Monitor *mon, const QDict *qdict)
> +{
> +    error_report("replay support not available");
> +}
> +ReplayInfo *qmp_query_replay(Error **errp)
> +{
> +    error_set(errp, ERROR_CLASS_COMMAND_NOT_FOUND,
> +              "replay support not available");
> +    return NULL;
> +}
> +void qmp_replay_break(int64_t icount, Error **errp)
> +{
> +    error_set(errp, ERROR_CLASS_COMMAND_NOT_FOUND,
> +              "replay support not available");
> +}
> +void qmp_replay_delete_break(Error **errp)
> +{
> +    error_set(errp, ERROR_CLASS_COMMAND_NOT_FOUND,
> +              "replay support not available");
> +}
> +void qmp_replay_seek(int64_t icount, Error **errp)
> +{
> +    error_set(errp, ERROR_CLASS_COMMAND_NOT_FOUND,
> +              "replay support not available");
> +}
> diff --git a/tests/ptimer-test-stubs.c b/tests/ptimer-test-stubs.c
> index e935a1395e..7f801a4d09 100644
> --- a/tests/ptimer-test-stubs.c
> +++ b/tests/ptimer-test-stubs.c
> @@ -122,8 +122,3 @@ void qemu_bh_delete(QEMUBH *bh)
>   {
>       g_free(bh);
>   }
> -
> -void replay_bh_schedule_event(QEMUBH *bh)
> -{
> -    bh->cb(bh->opaque);
> -}
> diff --git a/tests/qtest/qmp-cmd-test.c b/tests/qtest/qmp-cmd-test.c
> index 8a4c570e83..1c7186e53c 100644
> --- a/tests/qtest/qmp-cmd-test.c
> +++ b/tests/qtest/qmp-cmd-test.c
> @@ -31,6 +31,9 @@ static int query_error_class(const char *cmd)
>   #ifndef CONFIG_SPICE
>           { "query-spice", ERROR_CLASS_COMMAND_NOT_FOUND },
>   #endif
> +#ifndef CONFIG_TCG
> +        { "query-replay", ERROR_CLASS_COMMAND_NOT_FOUND },
> +#endif
>   #ifndef CONFIG_VNC
>           { "query-vnc", ERROR_CLASS_GENERIC_ERROR },
>           { "query-vnc-servers", ERROR_CLASS_GENERIC_ERROR },
> diff --git a/ui/input.c b/ui/input.c
> index 4791b089c7..8675e8ad09 100644
> --- a/ui/input.c
> +++ b/ui/input.c
> @@ -375,7 +375,11 @@ void qemu_input_event_send(QemuConsole *src, InputEvent *evt)
>           return;
>       }
>   
> -    replay_input_event(src, evt);
> +    if (replay_events_enabled()) {
> +        replay_input_event(src, evt);
> +    } else {
> +        qemu_input_event_send_impl(src, evt);
> +    }
>   }
>   
>   void qemu_input_event_sync_impl(void)
> @@ -401,7 +405,11 @@ void qemu_input_event_sync(void)
>           return;
>       }
>   
> -    replay_input_sync_event();
> +    if (replay_events_enabled()) {
> +        replay_input_sync_event();
> +    } else {
> +        qemu_input_event_sync_impl();
> +    }
>   }
>   
>   static InputEvent *qemu_input_event_new_key(KeyValue *key, bool down)
>