I'm trying to write a driver that will scan physical memory for a memory forensics application. From the research that I've done I see that the kernel API MmMapIoSpace has been used to accomplish this. I am a hobbyist and I know that this has been discussed before on this forum but I have specific questions. To use the function you must specify the permitted caching behavior using the MEMORY_CACHING_TYPE enumeration. The Windows documentation for the enumeration states that:
Processor translation buffers cache virtual to physical address translations. These translation buffers allow many virtual addresses to map a single physical address.
I thought that the purpose of caching address translations was so that every reference to a virtual address would not have to result in using page tables to translate the address into a physical address? What would be the purpose of multiple virtual addresses mapping a single physical address?
_...if a driver maps two different virtual address ranges to the same physical address, it must ensure that it specifies the same caching behavior for both. _
The MmMapIoSpace routine maps a given physical address range to system space. What happens if more than one driver attempts to map the same physical address at the same time while specifiying different caching attributes?
It looks like you're new here. If you want to get involved, click one of these buttons!
|Upcoming OSR Seminars|
|OSR has suspended in-person seminars due to the Covid-19 outbreak. But, don't miss your training! Attend via the internet instead!||Kernel Debugging||30 Mar 2020||OSR Seminar Space|
|Developing Minifilters||20 Apr 2020||LIVE ONLINE|
|Writing WDF Drivers||11 May 2020||LIVE ONLINE|
|Internals & Software Drivers||28 Sept 2020||Dulles, VA|