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Author Topic: Virtual Memory Mapping  (Read 104 times)

torne

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Virtual Memory Mapping
« on: February 07, 2006, 10:00:00 AM »

I've looked all over the interwebs for an answer to this, but can't find a definitive answer:
Does the xbox, when running the MS kernel, use virtual memory mapping in the 'usual' way? (translating VA->PA via the page tables or TLB). If so, what does the virtual memory map look like? I realise it only runs one process at a time and thus there will be only one set of page tables, and that all code runs in ring 0 and thus there is no memory protection from the supervisor bits.. but if it's a Windows kernel under there I can't imagine it's using direct memory access...

The reason I'm curious is because if it does, then it seems like it would be possible to use a replacement page fault handler and desynced TLBs to hide modifications to kernel code, as used in some experimental rootkit developments on Windows and explained in Phrack #63. This might be amusing as it could, say, conceal the presence of nkpatcher or similar from detection by games. biggrin.gif

I've not done any xbox development other than working on xbox-linux kernel code, but my day job is an embedded OS kernel developer, so please don't assume I don't know what I'm talking about in general.. it's just the xbox specifics I don't know about yet.
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