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?
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