[vbox-dev] Memory address trace

[Klaus Espenlaub]

Hi Paulo,

On 25.07.2013 19:00, paulo garcia wrote:
> Hello
>
> Is it possible to use VirtualBox to generate guest memory access address
> traces? (both guest virtual or guest physical addresses would be fine)

No, this would cause a giant slowdown, and wouldn't work in hardware 
virtualization mode and raw mode. Effectively it'd only have a chance in 
the lowest possible virtualization code path, which in a normal 
VirtualBox isn't used much, the recompiler. Actually the recompiler 
loses instruction address references to a certain extent, something 
which would need to be fixed by adding instrumentation code.

> I am browsing the source code, trying to find a place where guest memory
> addresses (for both instructions and data) are known, but could not find
> it yet......

The whole point of efficient virtualization is not needing to know such 
detailed information, and that's the reason why there is no such option. 
It would be a big amount of work to add additional instrumentation to 
catch the information you want (with unclear use case...) reliably, and 
the VM would run very slowly.

Klaus

>
> Best regards,
> Paulo