Re: [Qemu-devel] [PATCH] target-i386: update fp status fix

[TeLeMan]

I suggest using cpu_set_fpuc() like cpu_set_mxcsr().

On Tue, Sep 16, 2014 at 1:51 PM, TeLeMan <address@hidden> wrote:
> On Tue, Sep 16, 2014 at 1:42 PM, TeLeMan <address@hidden> wrote:
>> update_fp_status() should be used after all of env->fpuc changes :
>> helper_fldcw(), helper_fninit(), helper_fldenv()
>> ,helper_fxrstor(), helper_fsave(), x86_cpu_reset(), cpu_post_load().
>
> missing one: x86_cpu_gdb_write_register().
>
>>
>> On Mon, Sep 15, 2014 at 7:17 PM, Pavel Dovgalyuk
>> <address@hidden> wrote:
>>> This patch adds calls to update_fp_status() function from several
>>> places where FPU state is changed. These calls update status of
>>> softfloat library and prevent bugs caused by non-coherent rounding
>>> settings of the FPU and softfloat.
>>>
>>> Signed-off-by: Pavel Dovgalyuk <address@hidden>
>>> ---
>>>  target-i386/cpu.c        |    1 +
>>>  target-i386/cpu.h        |    1 +
>>>  target-i386/fpu_helper.c |    5 ++++-
>>>  target-i386/machine.c    |    2 +-
>>>  4 files changed, 7 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
>>> index 217500c..0ebedb0 100644
>>> --- a/target-i386/cpu.c
>>> +++ b/target-i386/cpu.c
>>> @@ -2573,6 +2573,7 @@ static void x86_cpu_reset(CPUState *s)
>>>          env->fptags[i] = 1;
>>>      }
>>>      env->fpuc = 0x37f;
>>> +    update_fp_status(env);
>>>
>>>      env->mxcsr = 0x1f80;
>>>      env->xstate_bv = XSTATE_FP | XSTATE_SSE;
>>> diff --git a/target-i386/cpu.h b/target-i386/cpu.h
>>> index e634d83..42bda46 100644
>>> --- a/target-i386/cpu.h
>>> +++ b/target-i386/cpu.h
>>> @@ -1249,6 +1249,7 @@ void QEMU_NORETURN raise_interrupt(CPUX86State *nenv, 
>>> int intno, int is_int,
>>>  /* cc_helper.c */
>>>  extern const uint8_t parity_table[256];
>>>  uint32_t cpu_cc_compute_all(CPUX86State *env1, int op);
>>> +void update_fp_status(CPUX86State *env);
>>>
>>>  static inline uint32_t cpu_compute_eflags(CPUX86State *env)
>>>  {
>>> diff --git a/target-i386/fpu_helper.c b/target-i386/fpu_helper.c
>>> index 1b2900d..a8ffba9 100644
>>> --- a/target-i386/fpu_helper.c
>>> +++ b/target-i386/fpu_helper.c
>>> @@ -537,7 +537,7 @@ uint32_t helper_fnstcw(CPUX86State *env)
>>>      return env->fpuc;
>>>  }
>>>
>>> -static void update_fp_status(CPUX86State *env)
>>> +void update_fp_status(CPUX86State *env)
>>>  {
>>>      int rnd_type;
>>>
>>> @@ -1006,6 +1006,7 @@ void helper_fstenv(CPUX86State *env, target_ulong 
>>> ptr, int data32)
>>>          cpu_stw_data(env, ptr + 10, 0);
>>>          cpu_stw_data(env, ptr + 12, 0);
>>>      }
>>> +    update_fp_status(env);
>>>  }
>>>
>>>  void helper_fldenv(CPUX86State *env, target_ulong ptr, int data32)
>>> @@ -1055,6 +1056,7 @@ void helper_fsave(CPUX86State *env, target_ulong ptr, 
>>> int data32)
>>>      env->fptags[5] = 1;
>>>      env->fptags[6] = 1;
>>>      env->fptags[7] = 1;
>>> +    update_fp_status(env);
>>>  }
>>>
>>>  void helper_frstor(CPUX86State *env, target_ulong ptr, int data32)
>>> @@ -1158,6 +1160,7 @@ void helper_fxrstor(CPUX86State *env, target_ulong 
>>> ptr, int data64)
>>>      }
>>>
>>>      env->fpuc = cpu_lduw_data(env, ptr);
>>> +    update_fp_status(env);
>>>      fpus = cpu_lduw_data(env, ptr + 2);
>>>      fptag = cpu_lduw_data(env, ptr + 4);
>>>      env->fpstt = (fpus >> 11) & 7;
>>> diff --git a/target-i386/machine.c b/target-i386/machine.c
>>> index 16d2f6a..2922c97 100644
>>> --- a/target-i386/machine.c
>>> +++ b/target-i386/machine.c
>>> @@ -315,13 +315,13 @@ static int cpu_post_load(void *opaque, int version_id)
>>>      env->hflags &= ~HF_CPL_MASK;
>>>      env->hflags |= (env->segs[R_SS].flags >> DESC_DPL_SHIFT) & HF_CPL_MASK;
>>>
>>> -    /* XXX: restore FPU round state */
>>>      env->fpstt = (env->fpus_vmstate >> 11) & 7;
>>>      env->fpus = env->fpus_vmstate & ~0x3800;
>>>      env->fptag_vmstate ^= 0xff;
>>>      for(i = 0; i < 8; i++) {
>>>          env->fptags[i] = (env->fptag_vmstate >> i) & 1;
>>>      }
>>> +    update_fp_status(env);
>>>
>>>      cpu_breakpoint_remove_all(cs, BP_CPU);
>>>      cpu_watchpoint_remove_all(cs, BP_CPU);
>>>
>>>