Re: [Qemu-devel] [PATCH 2/3] target-i386: Fix SSE status flag corruption

[Paolo Bonzini <pbonzini@redhat.com>]

Il 25/02/2014 08:30, Richard Henderson ha scritto:
> When we restore the mxcsr register with FXRSTOR, or set it with gdb,
> we need to update the various SSE status flags in CPUX86State
>
> Reported-by: Richard Purdie <richard.purdie@linuxfoundation.org>
> Signed-off-by: Richard Henderson <rth@twiddle.net>
> ---
> Differs from Purdie's patch primarily in fixing gdb too.  And that
> required exporting update_sse_status.  Which suggested that the name
> and interface be changed to match the norm.
>
>
> r~
> ---
>  target-i386/cpu.h        |  3 +++
>  target-i386/fpu_helper.c | 15 ++++++++-------
>  target-i386/gdbstub.c    |  2 +-
>  3 files changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/target-i386/cpu.h b/target-i386/cpu.h
> index 1b94f0f..5d3f143 100644
> --- a/target-i386/cpu.h
> +++ b/target-i386/cpu.h
> @@ -1259,6 +1259,9 @@ static inline void cpu_load_efer(CPUX86State *env, uint64_t val)
>      }
>  }
>
> +/* fpu_helper.c */
> +void cpu_set_mxcsr(CPUX86State *env, uint32_t val);
> +
>  /* svm_helper.c */
>  void cpu_svm_check_intercept_param(CPUX86State *env1, uint32_t type,
>                                     uint64_t param);
> diff --git a/target-i386/fpu_helper.c b/target-i386/fpu_helper.c
> index c0427fe..de7ba76 100644
> --- a/target-i386/fpu_helper.c
> +++ b/target-i386/fpu_helper.c
> @@ -1179,7 +1179,7 @@ void helper_fxrstor(CPUX86State *env, target_ulong ptr, int data64)
>
>      if (env->cr[4] & CR4_OSFXSR_MASK) {
>          /* XXX: finish it */
> -        env->mxcsr = cpu_ldl_data(env, ptr + 0x18);
> +        cpu_set_mxcsr(env, cpu_ldl_data(env, ptr + 0x18));
>          /* cpu_ldl_data(env, ptr + 0x1c); */
>          if (env->hflags & HF_CS64_MASK) {
>              nb_xmm_regs = 16;
> @@ -1229,12 +1229,14 @@ floatx80 cpu_set_fp80(uint64_t mant, uint16_t upper)
>  #define SSE_RC_CHOP         0x6000
>  #define SSE_FZ              0x8000
>
> -static void update_sse_status(CPUX86State *env)
> +void cpu_set_mxcsr(CPUX86State *env, uint32_t mxcsr)
>  {
>      int rnd_type;
>
> +    env->mxcsr = mxcsr;
> +
>      /* set rounding mode */
> -    switch (env->mxcsr & SSE_RC_MASK) {
> +    switch (mxcsr & SSE_RC_MASK) {
>      default:
>      case SSE_RC_NEAR:
>          rnd_type = float_round_nearest_even;
> @@ -1252,16 +1254,15 @@ static void update_sse_status(CPUX86State *env)
>      set_float_rounding_mode(rnd_type, &env->sse_status);
>
>      /* set denormals are zero */
> -    set_flush_inputs_to_zero((env->mxcsr & SSE_DAZ) ? 1 : 0, &env->sse_status);
> +    set_flush_inputs_to_zero((mxcsr & SSE_DAZ) ? 1 : 0, &env->sse_status);
>
>      /* set flush to zero */
> -    set_flush_to_zero((env->mxcsr & SSE_FZ) ? 1 : 0, &env->fp_status);
> +    set_flush_to_zero((mxcsr & SSE_FZ) ? 1 : 0, &env->fp_status);
>  }
>
>  void helper_ldmxcsr(CPUX86State *env, uint32_t val)
>  {
> -    env->mxcsr = val;
> -    update_sse_status(env);
> +    cpu_set_mxcsr(env, val);
>  }
>
>  void helper_enter_mmx(CPUX86State *env)
> diff --git a/target-i386/gdbstub.c b/target-i386/gdbstub.c
> index 15bebef..d34e535 100644
> --- a/target-i386/gdbstub.c
> +++ b/target-i386/gdbstub.c
> @@ -222,7 +222,7 @@ int x86_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
>              return 4;
>
>          case IDX_MXCSR_REG:
> -            env->mxcsr = ldl_p(mem_buf);
> +            cpu_set_mxcsr(env, ldl_p(mem_buf));
>              return 4;
>          }
>      }
>

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