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

[Steven]

On Thu, Aug 16, 2012 at 1:43 PM, Max Filippov <address@hidden> wrote:
> On Thu, Aug 16, 2012 at 9:37 PM, Max Filippov <address@hidden> wrote:
>> On Thu, Aug 16, 2012 at 9:29 PM, Steven <address@hidden> wrote:
>>> On Thu, Aug 16, 2012 at 1:00 PM, Max Filippov <address@hidden> wrote:
>>>> On Thu, Aug 16, 2012 at 8:36 PM, Steven <address@hidden> wrote:
>>>>> On Thu, Aug 16, 2012 at 4:02 AM, 陳韋任 (Wei-Ren Chen)
>>>>> <address@hidden> wrote:
>>>>>>> I would like to is there any function that could log the register
>>>>>>> content of the guest machine, like "info registers" in the qemu
>>>>>>> monitor mode.
>>>>>>
>>>>>>   Why not check how "info registes" be implemented in QEMU? ;)
>>>>>> I guess you just have to log env->regs or something like that.
>>>>> Thanks for pointing this out.
>>>>> I would like to get a trace of guest memory access. So I can not use
>>>>> "info registers".
>>>>> What I want to do is that when tcg fetches a load instruction at
>>>>> disas_insns(), the guest memory address should be calculated. For
>>>>
>>>> No, you don't want this, because the same translated code may be
>>>> invoked multiple times with different values in registers.
>>>>
>>>>> example, the tb has an instruction of mov 0x4(%ebx)  %eax.
>>>>> To calculate the address of 0x4(%ebx), I need to know the value of %ebx.
>>>>> Is this correct? Thanks.
>>>>
>>>> Why don't you just instrument actual memory access functions in
>>>> softmmu_template.h ?
>>> But this code only touches the s->pc. For registers in the load
>>> instruction, it won't generate the memory access code. So I need to
>>> add code to some function to get the guest memory address access.
>>
>> Take a close look at
>>
>> DATA_TYPE
>> glue(glue(glue(HELPER_PREFIX, ld), SUFFIX), MMUSUFFIX)(ENV_PARAM
>>                                                        target_ulong addr,
>>                                                        int mmu_idx)
>>
>> and
>>
>> void glue(glue(glue(HELPER_PREFIX, st), SUFFIX), MMUSUFFIX)(ENV_PARAM
>>                                                             target_ulong 
>> addr,
>>                                                             DATA_TYPE val,
>>                                                             int mmu_idx)
>>
>> At runtime they get addr, this is the virtual address of the memory access.
>> This file is included several times to instantiate these functions for
>> different memory access types.
>> A set of macros manipulates access size and whether it is code or data 
>> access.
>
> But maybe I got you wrong and by
>
>   What I want to do is that when tcg fetches a load instruction at
>   disas_insns(), the guest memory address should be calculated.
>
> you meant that you need to record code address that made an access,
> not the accessed data address?
>
I want to get the guest memory address in the instruction mov
0x4(%ebx)  %eax, whic is 0x4(%ebx).
Since %ebx is not resolved until the execution time, the code in
softmmu_header.h does not generate any hit or miss information.
Do you know any place that I could resolve the memory access address? Thanks.

> --
> Thanks.
> -- Max