Re: [PATCH 3/3] sysemu/replay: Restrict icount to system emulation

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 7/12/23 14:46, Philippe Mathieu-Daudé wrote:
> On 7/12/23 11:26, Philippe Mathieu-Daudé wrote:
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>> ---
>>   include/sysemu/cpu-timers.h |  2 +-
>>   include/sysemu/replay.h     |  9 ++++++---
>>   stubs/icount.c              | 19 -------------------
>>   3 files changed, 7 insertions(+), 23 deletions(-)
>>
>> diff --git a/include/sysemu/cpu-timers.h b/include/sysemu/cpu-timers.h
>> index 2e786fe7fb..188f67ee90 100644
>> --- a/include/sysemu/cpu-timers.h
>> +++ b/include/sysemu/cpu-timers.h
>> @@ -24,7 +24,7 @@ void cpu_timers_init(void);
>>    * 1 = Enabled - Fixed conversion of insn to ns via "shift" option
>>    * 2 = Enabled - Runtime adaptive algorithm to compute shift
>>    */
>> -#ifdef CONFIG_TCG
>> +#if defined(CONFIG_TCG) && !defined(CONFIG_USER_ONLY)
>>   extern int use_icount;
>>   #define icount_enabled() (use_icount)
>>   #else
>> diff --git a/include/sysemu/replay.h b/include/sysemu/replay.h
>> index 02fa75c783..8102fa54f0 100644
>> --- a/include/sysemu/replay.h
>> +++ b/include/sysemu/replay.h
>> @@ -1,6 +1,3 @@
>> -#ifndef SYSEMU_REPLAY_H
>> -#define SYSEMU_REPLAY_H
>> -
>>   /*
>>    * QEMU replay (system interface)
>>    *
>> @@ -11,6 +8,12 @@
>>    * See the COPYING file in the top-level directory.
>>    *
>>    */
>> +#ifndef SYSEMU_REPLAY_H
>> +#define SYSEMU_REPLAY_H
>> +
>> +#ifdef CONFIG_USER_ONLY
>> +#error Cannot include this header from user emulation
>> +#endif
>>   #include "exec/replay-core.h"
>>   #include "qapi/qapi-types-misc.h"
>> diff --git a/stubs/icount.c b/stubs/icount.c
>> index c39a65da92..ec8d150069 100644
>> --- a/stubs/icount.c
>> +++ b/stubs/icount.c
>> @@ -5,30 +5,11 @@
>>   int use_icount;
>> -void icount_update(CPUState *cpu)
>> -{
>> -    abort();
>> -}
>>   int64_t icount_get_raw(void)
>>   {
>>       abort();
>>       return 0;
>>   }
>> -int64_t icount_get(void)
>> -{
>> -    abort();
>> -    return 0;
>> -}
>> -int64_t icount_to_ns(int64_t icount)
>> -{
>> -    abort();
>> -    return 0;
>> -}
> 
> Build failure on HVF due to:
> 
>    pmu_init()
>     -> pm_events[]
>      -> INST_RETIRED
>       -> instructions_ns_per()
>        -> icount_to_ns()
> 
> So we need to keep the icount_to_ns() stub until we restrict
> ARM PMU code to TCG.

Alternatively, we can use as a preliminary patch:

-- >8 --
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 20e13215bb..48ab1e0523 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -939,11 +939,13 @@ static bool instructions_supported(CPUARMState *env)

  static uint64_t instructions_get_count(CPUARMState *env)
  {
+    assert(icount_enabled());
      return (uint64_t)icount_get_raw();
  }

  static int64_t instructions_ns_per(uint64_t icount)
  {
+    assert(icount_enabled());
      return icount_to_ns((int64_t)icount);
  }
  #endif
---