Re: [RFC v1 4/4] replay: do not build if TCG is not available

[Paolo Bonzini <pbonzini@redhat.com>]

On 09/10/20 17:21, Claudio Fontana wrote:
> replay requires icount, which needs TCG.
> 
> stub the needed functions in stub/,
> including errors for hmp and qmp commands.
> 
> Signed-off-by: Claudio Fontana <cfontana@suse.de>

Looks plausible, though probably I'd put it in replay/stubs.c and use
if_false to link it.

Paolo

> ---
>  migration/savevm.c         | 11 +++--
>  replay/meson.build         |  2 +-
>  stubs/replay.c             | 99 ++++++++++++++++++++++++++++++++++++++
>  tests/qtest/qmp-cmd-test.c |  3 ++
>  4 files changed, 110 insertions(+), 5 deletions(-)
> 
> 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/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/stubs/replay.c b/stubs/replay.c
> index 45ebe77fb9..ff35daf198 100644
> --- a/stubs/replay.c
> +++ b/stubs/replay.c
> @@ -103,3 +103,102 @@ bool replay_reverse_continue(void)
>  {
>      return false;
>  }
> +
> +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_bh_schedule_event(QEMUBH *bh)
> +{
> +}
> +void replay_breakpoint(void)
> +{
> +}
> +bool replay_can_snapshot(void)
> +{
> +    return false;
> +}
> +void replay_configure(struct QemuOpts *opts)
> +{
> +}
> +void replay_flush_events(void)
> +{
> +}
> +void replay_gdb_attached(void)
> +{
> +}
> +void replay_input_event(QemuConsole *src, InputEvent *evt)
> +{
> +}
> +void replay_input_sync_event(void)
> +{
> +}
> +void replay_net_packet_event(ReplayNetState *rns, unsigned flags,
> +                             const struct iovec *iov, int iovcnt)
> +{
> +}
> +ReplayNetState *replay_register_net(NetFilterState *nfs)
> +{
> +    return NULL;
> +}
> +bool replay_running_debug(void)
> +{
> +    return false;
> +}
> +void replay_shutdown_request(ShutdownCause cause)
> +{
> +}
> +void replay_start(void)
> +{
> +}
> +void replay_unregister_net(ReplayNetState *rns)
> +{
> +}
> +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\n");
> +}
> +void hmp_replay_break(Monitor *mon, const QDict *qdict)
> +{
> +    error_report("replay support not available\n");
> +}
> +void hmp_replay_delete_break(Monitor *mon, const QDict *qdict)
> +{
> +    error_report("replay support not available\n");
> +}
> +void hmp_replay_seek(Monitor *mon, const QDict *qdict)
> +{
> +    error_report("replay support not available\n");
> +}
> +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/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 },
>