[RFC,v8,06/21] replay: introduce icount event

This patch adds icount event to the replay subsystem. This event corresponds
to execution of several instructions and used to synchronize input events
in the replay phase.

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
---
 replay/replay-internal.c |   16 ++++++++++++++++
 replay/replay-internal.h |   20 ++++++++++++++++++++
 replay/replay.c          |   46 ++++++++++++++++++++++++++++++++++++++++++++++
 replay/replay.h          |    7 +++++++
 4 files changed, 89 insertions(+), 0 deletions(-)

On 22/01/2015 09:52, Pavel Dovgalyuk wrote:
> This patch adds icount event to the replay subsystem. This event corresponds
> to execution of several instructions and used to synchronize input events
> in the replay phase.
> 
> Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
> ---
>  replay/replay-internal.c |   16 ++++++++++++++++
>  replay/replay-internal.h |   20 ++++++++++++++++++++
>  replay/replay.c          |   46 ++++++++++++++++++++++++++++++++++++++++++++++
>  replay/replay.h          |    7 +++++++
>  4 files changed, 89 insertions(+), 0 deletions(-)
> 
> diff --git a/replay/replay-internal.c b/replay/replay-internal.c
> index f552dad..49b37a6 100755
> --- a/replay/replay-internal.c
> +++ b/replay/replay-internal.c
> @@ -10,6 +10,7 @@
>   */
>  
>  #include "qemu-common.h"
> +#include "replay.h"
>  #include "replay-internal.h"
>  
>  unsigned int replay_data_kind = -1;
> @@ -164,3 +165,18 @@ void replay_mutex_unlock(void)
>  {
>      qemu_mutex_unlock(&lock);
>  }
> +
> +/*! Saves cached instructions. */
> +void replay_save_instructions(void)
> +{
> +    if (replay_file && replay_mode == REPLAY_MODE_RECORD) {
> +        int diff = (int)(replay_get_current_step() - replay_state.current_step);
> +        if (first_cpu != NULL && diff > 0) {
> +            replay_mutex_lock();
> +            replay_put_event(EVENT_INSTRUCTION);
> +            replay_put_dword(diff);
> +            replay_state.current_step += diff;
> +            replay_mutex_unlock();
> +        }
> +    }
> +}
> diff --git a/replay/replay-internal.h b/replay/replay-internal.h
> index 50ce29b..4d661a1 100755
> --- a/replay/replay-internal.h
> +++ b/replay/replay-internal.h
> @@ -14,6 +14,19 @@
>  
>  #include <stdio.h>
>  
> +enum ReplayEvents {
> +    /* for instruction event */
> +    EVENT_INSTRUCTION
> +};
> +
> +typedef struct ReplayState {
> +    /*! Current step - number of processed instructions and timer events. */
> +    uint64_t current_step;
> +    /*! Number of instructions to be executed before other events happen. */
> +    int instructions_count;
> +} ReplayState;
> +extern ReplayState replay_state;
> +
>  extern unsigned int replay_data_kind;
>  extern unsigned int replay_has_unread_data;
>  
> @@ -54,4 +67,11 @@ void replay_save_instructions(void);
>      Terminates the program in case of error. */
>  void validate_data_kind(int kind);
>  
> +/*! Skips async events until some sync event will be found. */
> +bool skip_async_events(int stop_event);
> +/*! Skips async events invocations from the input,
> +    until required data kind is found. If the requested data is not found
> +    reports an error and stops the execution. */
> +void skip_async_events_until(unsigned int kind);
> +
>  #endif
> diff --git a/replay/replay.c b/replay/replay.c
> index 5ce066f..a43bbbc 100755
> --- a/replay/replay.c
> +++ b/replay/replay.c
> @@ -9,6 +9,52 @@
>   *
>   */
>  
> +#include "qemu-common.h"
>  #include "replay.h"
> +#include "replay-internal.h"
> +#include "qemu/timer.h"
>  
>  ReplayMode replay_mode = REPLAY_MODE_NONE;
> +
> +ReplayState replay_state;
> +
> +bool skip_async_events(int stop_event)
> +{
> +    bool res = false;
> +
> +    /* nothing to skip - not all instructions used */
> +    if (replay_state.instructions_count != 0
> +        && replay_has_unread_data) {
> +        return stop_event == EVENT_INSTRUCTION;
> +    }
> +
> +    while (true) {
> +        replay_fetch_data_kind();
> +        if (stop_event == replay_data_kind) {
> +            res = true;
> +        }
> +        switch (replay_data_kind) {
> +        case EVENT_INSTRUCTION:
> +            replay_state.instructions_count = replay_get_dword();
> +            return res;
> +        default:
> +            /* clock, time_t, checkpoint and other events */
> +            return res;
> +        }
> +    }
> +    return res;
> +}
> +
> +void skip_async_events_until(unsigned int kind)
> +{
> +    if (!skip_async_events(kind)) {
> +        fprintf(stderr, "%"PRId64": Read data kind %d instead of expected %d\n",
> +            replay_get_current_step(), replay_data_kind, kind);
> +        exit(1);
> +    }
> +}
> +
> +uint64_t replay_get_current_step(void)
> +{
> +    return cpu_get_icount_raw();
> +}
> diff --git a/replay/replay.h b/replay/replay.h
> index d6b73c3..a03c748 100755
> --- a/replay/replay.h
> +++ b/replay/replay.h
> @@ -12,8 +12,15 @@
>   *
>   */
>  
> +#include <stdbool.h>
> +#include <stdint.h>
>  #include "qapi-types.h"
>  
>  extern ReplayMode replay_mode;
>  
> +/* Processing the instructions */
> +
> +/*! Returns number of executed instructions. */
> +uint64_t replay_get_current_step(void);
> +
>  #endif
> 

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>