Difference between kernel logical address and kernel virtual address

[Anirban Roy]

Hi,

There are 2 type of virtual address.
One which needs Page table to do the convertion from VIR to PHY.
other which is offset to PHYSICAL_PAGE_OFFSET. [ this is actually also
called as logical address ]. One can directly calculate the Physical
address if Logical address is given.

virtual addess where u need a Page Table to do a conversion.

Virtual address - one way fo calculation . [ address got from vmalloc ]

         CR3 + PGD(Virtual Address ) + PMD ( virtual address )+ PTE (
Virtual address )= Physical address

Logical address below is called LOW MEM [ usually get from kmalloc ]

    Virtual address - PHYSICAL_PAGE_OFFSET = physical address.

regards
Anirban Roy



On Sat, Aug 18, 2018 at 8:18 AM, Abhinav Misra
<abhitheextremeeng at gmail.com> wrote:
> Hi,
>
> In LDD3 book at Ch-15 they mentioned all types of address used in the
> kernel.
> But wrt the book, not able to understand the difference between kernel
> logical and virtual address.
>
> Can somebody elaborate the same with some eg.
>
> BR,Abhinav
>
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