Mapping between Host virtual address and guest physical address

Mapping between Host virtual address and guest physical address

[Muhui Jiang]

[-- Attachment #1: Type: text/plain, Size: 588 bytes --]

Dear All

I am recently using qemu-system-arm to boot a linux uImage.

I would like to do some dynamic instrumentation on the uncompressed kernel.
It seems that I need to focus on two key points.

Firstly, I need to know when the kernel is uncompressed, which means the
compression process is finished. By analyzing the vmlinux.elf  and the
trace I can figure it out.

Secondly, I need to know where the uncompressed is, which means where the
uncompressed linux kernel (Before translated into tcg) stores in the
virtual address of qemu. Does anyone have ideas? Many Thanks

Regards
Muhui

[-- Attachment #2: Type: text/html, Size: 745 bytes --]

Re: Mapping between Host virtual address and guest physical address

[Dr. David Alan Gilbert]

* Muhui Jiang (jiangmuhui@gmail.com) wrote:
> Dear All
> 
> I am recently using qemu-system-arm to boot a linux uImage.
> 
> I would like to do some dynamic instrumentation on the uncompressed kernel.
> It seems that I need to focus on two key points.
> 
> Firstly, I need to know when the kernel is uncompressed, which means the
> compression process is finished. By analyzing the vmlinux.elf  and the
> trace I can figure it out.
> 
> Secondly, I need to know where the uncompressed is, which means where the
> uncompressed linux kernel (Before translated into tcg) stores in the
> virtual address of qemu. Does anyone have ideas? Many Thanks

There's are some existing HMP monitor commands for this type of
debugging:

gpa2hpa addr -- print the host physical address corresponding to a guest physical address
gpa2hva addr -- print the host virtual address corresponding to a guest physical address
gva2gpa addr -- print the guest physical address corresponding to a guest virtual address

so I think you're saying you want gpa2hva

Dave

> Regards
> Muhui
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK