[Qemu-discuss] inspect the instruction fetch stream

[Hongil Yoon]

Hi, 

I am using QEMU to analyze memory access stream especially for instruction 
fetch.
What I would like to obtain is a virtual and physical address mapping of the 
instruction stream.

On memory access, softmmu part is called. So, the mapping can be obtained after 
a tlb is looked up. My concern is some instructions could be missed because of 
the usage of tb cache.

First, I’d like to make sure my understanding suggested below is correct:
1. Memory access for instructions occurs while translating instructions for a 
new tb.
2. The tb will be kept in the tb cache for later user.
3. If the tb is looked up again, the translated instructions are processed 
without any memory access.

If my understanding is correct, I think the simplest way to analyze memory 
access stream is to disable tb cache (although it could slow down the system). 
Is there any other simpler way to do that?

Lastly, “-singlestep” option will keep one instruction in a tb. I think some 
instructions are still likely to be missed although single step is set as long 
as tb cache is being used. Do you have any idea about this?

Thanks, in advance. 
 

Best regards,

Hongil