[Qemu-devel] Host virtual to target physical memory addresses

[Qemu-devel] Host virtual to target physical memory addresses

[Christoffer Dall]

I am trying to find out how emulated physical addresses relate to host 
allocated virtual addresses for ARM system emulation.

Specifically, given a host virtual address allocated by QEMU for some 
memory region, I would like to find the corresponding guest (target) 
physical address.

I have gone through the code for the integrator board and for the main 
memory I can see that both qemu_ram_alloc and 
cpu_register_physical_memory are called. I understand that the first 
deals with actually allocating the virtual addresses needed for the 
memory area and the second registers the memory with the virtual CPU.

During cpu_register_physical_memory, eventually phys_page_find_alloc is 
called, and I can see that it is related to the software mmu code in 
target-arm/helper.c, but I am getting somewhat lost in the concepts 
RAMBlock, ram_offset and PhysPageDesc.

Is there some documentation on this that I can study or can anyone give 
me a quick run-down on the concepts?

Any help will be greatly appreciated.

Thank you.

Best regards,
Christoffer Dall