How to access physical memory

宋辰伟 scwsy00 at gmail.com
Mon Dec 24 03:24:12 UTC 2018


Hi I'm the new here . And I have some questions with pmap.

[image: 1545542790461.png]


See `*pml4` is the physical address of a page with some flag. And then
updated the address to the Direct Map Space. Then We calculate the offset
of the real pdp we need .

How could it access to `*pdp`? it is a virtual addr in Direct Map Space.
Why don't change the physical space directly since we have the physical
page already.


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