Linux also maps a set of contiguousvirtual pages (equal in size to the total amount of DRAM in the system) to the corresponding set of contiguous physical pages. This provides the kernel with a convenient way to access any specific location in physical memory
I am a little bit confused here. I think it refers to the second section "Physical memory". but what does it mean by it i is a convenient way to access any specific location in physical memory? if you want to access a specific location, cpu will still have to issue an instruction that has virtual address which can be used by TLB and then a physical address will be produced to access physical memory, so what the "physical memory" section is really for?