Re: [Qemu-devel] qemu log function to print out the registers of the guest

[Steven]

Hi, Max,
I appreciate your help and got some results using your patch. But I
still have two questions as blow.

>> I see that with the following patch
>>
>> diff --git a/softmmu_template.h b/softmmu_template.h
>> index b8bd700..2d02133 100644
>> --- a/softmmu_template.h
>> +++ b/softmmu_template.h
>> @@ -114,6 +114,7 @@ glue(glue(glue(HELPER_PREFIX, ld), SUFFIX),
>> MMUSUFFIX)(ENV_PARAM
>>      target_phys_addr_t ioaddr;
>>      uintptr_t retaddr;
>>
>> +    fprintf(stderr, "%s: %08x\n", __func__, addr);
>>      /* test if there is match for unaligned or IO access */
>>      /* XXX: could done more in memory macro in a non portable way */
>>      index = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
>>
>> I get some memory accesses logged, but not all. That's due to fast
>> path in tcg_out_qemu_ld
>> in case there's TLB hit. I guess you can play with tcg_out_qemu_ld and
>> make it produce a call
>> to a helper function, like qemu_ld_helpers, that will print addresses
>> for all memory access
>> attempts.
>
> Easier solution would be to disable fast path and always go through
> softmmu helpers, like this (specific for x86 host):
>
> diff --git a/softmmu_template.h b/softmmu_template.h
> index b8bd700..2d02133 100644
> --- a/softmmu_template.h
> +++ b/softmmu_template.h
> @@ -114,6 +114,7 @@ glue(glue(glue(HELPER_PREFIX, ld), SUFFIX),
> MMUSUFFIX)(ENV_PARAM
>      target_phys_addr_t ioaddr;
>      uintptr_t retaddr;
>
> +    fprintf(stderr, "%s: %08x\n", __func__, addr);
>      /* test if there is match for unaligned or IO access */
>      /* XXX: could done more in memory macro in a non portable way */
>      index = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
> diff --git a/tcg/i386/tcg-target.c b/tcg/i386/tcg-target.c
> index da17bba..ec68c19 100644
> --- a/tcg/i386/tcg-target.c
> +++ b/tcg/i386/tcg-target.c
> @@ -1062,7 +1062,7 @@ static inline void tcg_out_tlb_load(TCGContext
> *s, int addrlo_idx,
>      tcg_out_mov(s, type, r0, addrlo);
>
>      /* jne label1 */
> -    tcg_out8(s, OPC_JCC_short + JCC_JNE);
> +    tcg_out8(s, OPC_JMP_short);
>      label_ptr[0] = s->code_ptr;
>      s->code_ptr++;
>

IN:
0x00000000c13e3a33:  mov    0x8(%ebp),%ebx (guest code in the tb)
__ldl_mmu: c13a9fdc

So 0xc13a9fdc is the guest virtual memory address of 0x8(%ebp). Is this correct?

IN:
0x00000000c13e3a36:  mov    %eax,-0x10(%ebp)
However, for this instruction, no ldl_mmu is logged.
Does that mean the patch you provided does not cover this case?
Thanks.

>
> --
> Thanks.
> -- Max