[AMD Official Use Only - General] Hello Boris, >>So essentially we want to map the faulting address to a RMP entry, >>considering the fact that a 2M host hugepage can be mapped as 4K RMP table entries and 1G host hugepage can be mapped as 2M RMP table entries. >So something's seriously confusing or missing here because if you fault on a 2M host page and the underlying RMP entries are 4K then you can use pte_index(). >If the host page is 1G and the underlying RMP entries are 2M, pmd_index() should work here too. >But this piecemeal back'n'forth doesn't seem to resolve this so I'd like to ask you pls to sit down, take your time and give a detailed example of the two possible cases and what the difference is between pte_/pmd_index and your way. Feel free to >add actual debug output and paste it here. There is 1 64-bit RMP entry for every physical 4k page of DRAM, so essentially every 4K page of DRAM is represented by a RMP entry. So even if host page is 1G and underlying (smashed/split) RMP entries are 2M, the RMP table entry has to be indexed to a 4K entry corresponding to that. If it was simply a 2M entry in the RMP table, then pmd_index() will work correctly. Considering the following example: address = 0x40200000; level = PG_LEVEL_1G; pfn = 0x40000; pfn |= pmd_index(address); This will give the RMP table index as 0x40001. And it will work if the RMP table entry was simply a 2MB entry, but we need to map this further to its corresponding 4K entry. With the same example as above: level = PG_LEVEL_1G; mask = pages_per_hpage(level) - pages_per_hpage(level - 1); pfn |= (address >> PAGE_SHIFT) & mask; This will give the RMP table index as 0x40200. Which is the correct RMP table entry for a 2MB smashed/split 1G page mapped further to its corresponding 4K entry. Hopefully this clarifies why pmd_index() can't be used here. Thanks, Ashish