Re: [Qemu-ppc] Intercepting memory reads/writes

[Alexander Graf]

On 21.08.14 15:29, Brandon Williams wrote:
> 
> On Thu, Aug 21, 2014 at 9:22 AM, Alexander Graf <address@hidden
> <mailto:address@hidden>> wrote:
> 
> 
> 
>     > Am 21.08.2014 um 15:09 schrieb Brandon Williams
>     <address@hidden <mailto:address@hidden>>:
>     >
>     > Hello,
>     >
>     > I am interested in customizing qemu-system-ppc to basically
>     "watch" a certain memory address and do something when the target
>     application reads/writes to this address.  Would this be in the MMU?
>     Could someone point me to the right spot in the code?
> 
>     Do you want to do this on virtual or physical access? Also, would
>     whatever you want to do work from a gdb script that you can attach
>     to qemu's gdbstub?
> 
>     Alex
> 
> 
> As the target application writes to a virtual address, I would like to
> add some sort of callback function in QEMU to write that data to a real,
> physical address so that the data could be read outside of QEMU from a
> different application - and vice versa for memory reads at this
> location.  Basically the target application that is going to be running
> in QEMU will be reading/writing at a specified virtual address and I
> want to somehow access that memory outside of the QEMU environment.  I
> would be open to a gdb script if it wouldn't interrupt the flow of the
> program execution.

I think this would be perfectly possible with gdbstub. Just add a
watchpoint (awatch) at the virtual address and trace all accesses. You
can then use that trace and interpret it from your external application.

Keep in mind that none of this has anything to do with PowerPC specifics
though, so you're writing this to the wrong mailing list ;).


Alex