Page table queries

[anish singh]

As i understood whenver a user space program is run it is represented in
kernel using VMA which is managed by struct mm_struct
and whenever the program is trying to read/write to a memory location in
user space it will be directed to physical address using PAGE TABLE
translation done by struct mm_struct(done in kernel space).Am i right?

Suppose a simple driver wants the user to directly access its device memory
then we use mmap.This mmap associates a set of user space virtual address
with device driver memory and it is done by creating kernel page tables for
the user space virtual addresses.Is the page table translation done
everytime whenever user space does read/write to the device memory??

In .nopage function call we return the page associated with the physical
address which the user wants to associate with user space virtual address.Is
the page address returned by the nopage function same as seen by the user or
will it be converted to user space virtual address(range between 0-2 GB)?

Thanks for reading.
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