Re: [Qemu-devel] Final call for help: x86: enter instruction bug: PATCH

[Fabrice Bellard <fabrice@bellard.org>]

Thank you for the enter bug fix. Your patch has still one bug if the SS 
segment is 16 bit ('env->segs[R_SS].base + EBP' is not correct). I am 
making a better fix.

Fabrice.

Stefan Kisdaroczi wrote:
> Hi,
> 
> I have attached a patch which fixes the emulation of the i386 enter
> instruction. My Test-App is using the enter levels 1-3 is now working
> identical under qemu and a real i386 (checked registers and stack
> contens with debugger, 16-Bit Mode).
> 
> Please review. Thank you.
> 
> greetings
> kisda
> 
> 
> ------------------------------------------------------------------------
> 
> diff -uNrp qemu.orig/target-i386/exec.h qemu/target-i386/exec.h
> --- qemu.orig/target-i386/exec.h	2004-11-14 13:43:20.000000000 +0100
> +++ qemu/target-i386/exec.h	2004-11-14 13:47:31.000000000 +0100
> @@ -167,6 +167,7 @@ void helper_divl_EAX_T0(uint32_t eip);
>  void helper_idivl_EAX_T0(uint32_t eip);
>  void helper_cmpxchg8b(void);
>  void helper_cpuid(void);
> +void helper_enter_level(uint8_t *dst_ptr, int level, int data32);
>  void helper_sysenter(void);
>  void helper_sysexit(void);
>  void helper_rdtsc(void);
> diff -uNrp qemu.orig/target-i386/helper.c qemu/target-i386/helper.c
> --- qemu.orig/target-i386/helper.c	2004-11-14 13:43:20.000000000 +0100
> +++ qemu/target-i386/helper.c	2004-11-14 13:47:31.000000000 +0100
> @@ -1068,6 +1068,27 @@ void helper_cpuid(void)
>      }
>  }
>  
> +void helper_enter_level( uint8_t *dst_ptr, int level, int data32 )
> +{
> +  int ofs = 0;
> +  uint8_t *src_ptr = env->segs[R_SS].base + EBP;
> +
> +  if (data32) {
> +    /* 32 bit */
> +    while (--level) {
> +      ofs -= 4;
> +      stl( dst_ptr + ofs, ldl( src_ptr + ofs ) );
> +    }
> +  }
> +  else {
> +    /* 16 bit */
> +    while (--level) {
> +      ofs -= 2;
> +      stw( dst_ptr + ofs, lduw( src_ptr + ofs ) );
> +    }
> +  }
> +}
> +
>  void helper_lldt_T0(void)
>  {
>      int selector;
> diff -uNrp qemu.orig/target-i386/op.c qemu/target-i386/op.c
> --- qemu.orig/target-i386/op.c	2004-11-14 13:43:20.000000000 +0100
> +++ qemu/target-i386/op.c	2004-11-14 13:47:31.000000000 +0100
> @@ -695,6 +695,11 @@ void OPPROTO op_cpuid(void)
>      helper_cpuid();
>  }
>  
> +void OPPROTO op_enter_level(void)
> +{
> +    helper_enter_level((uint8_t *)A0, PARAM1, PARAM2);
> +}
> +
>  void OPPROTO op_sysenter(void)
>  {
>      helper_sysenter();
> diff -uNrp qemu.orig/target-i386/translate.c qemu/target-i386/translate.c
> --- qemu.orig/target-i386/translate.c	2004-11-14 13:43:20.000000000 +0100
> +++ qemu/target-i386/translate.c	2004-11-14 13:51:57.000000000 +0100
> @@ -1694,11 +1694,10 @@ static void gen_popa(DisasContext *s)
>  /* XXX: check this */
>  static void gen_enter(DisasContext *s, int esp_addend, int level)
>  {
> -    int ot, level1, addend, opsize;
> +    int ot, opsize;
>  
>      ot = s->dflag + OT_WORD;
>      level &= 0x1f;
> -    level1 = level;
>      opsize = 2 << s->dflag;
>  
>      gen_op_movl_A0_ESP();
> @@ -1712,19 +1711,13 @@ static void gen_enter(DisasContext *s, i
>      gen_op_mov_TN_reg[OT_LONG][0][R_EBP]();
>      gen_op_st_T0_A0[ot + s->mem_index]();
>      if (level) {
> -        while (level--) {
> -            gen_op_addl_A0_im(-opsize);
> -            gen_op_addl_T0_im(-opsize);
> -            gen_op_st_T0_A0[ot + s->mem_index]();
> -        }
> -        gen_op_addl_A0_im(-opsize);
> +        if (level > 1)
> +            gen_op_enter_level( level, s->dflag );
> +        gen_op_addl_A0_im(-opsize * level);
>          gen_op_st_T1_A0[ot + s->mem_index]();
>      }
>      gen_op_mov_reg_T1[ot][R_EBP]();
> -    addend = -esp_addend;
> -    if (level1)
> -        addend -= opsize * (level1 + 1);
> -    gen_op_addl_T1_im(addend);
> +    gen_op_addl_T1_im( -esp_addend + (-opsize * level) );
>      gen_op_mov_reg_T1[ot][R_ESP]();
>  }
>  
> 
> 
> ------------------------------------------------------------------------
> 
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