On 10/06/18 at 04:38pm, Ingo Molnar wrote: > +Notes: > + > + - Negative addresses such as "-23 TB" are absolute addresses in bytes, > counted down > + from the top of the 64-bit address space. It's easier to understand the > layout > + when seen both in absolute addresses and in distance-from-top notation. > + > + For example 0xffffe90000000000 == -23 TB, it's 23 TB lower than the top > of the > + 64-bit address space (ffffffffffffffff). > + > + Note that as we get closer to the top of the address space, the notation > changes > + from TB to GB and then MB/KB. > + > + - "16M TB" might look weird at first sight, but it's an easier to visualize > size > + notation than "16 EB", which few will recognize at first sight as 16 > exabytes. > + It also shows it nicely how incredibly large 64-bit address space is.
Thanks, this looks much better than the old version and my change. Reviewed-by: Baoquan He <b...@redhat.com> Thanks Baoquan > + > +======================================================================================================================== > + Start addr | Offset | End addr | Size | VM area > description > +======================================================================================================================== > + | | | | > + 0000000000000000 | 0 | 00007fffffffffff | 128 TB | user-space > virtual memory, different per mm > +__________________|____________|__________________|_________|___________________________________________________________ > + | | | | > + 0000800000000000 | +128 TB | ffff7fffffffffff | ~16M TB | ... huge, > almost 64 bits wide hole of non-canonical > + | | | | virtual > memory addresses up to the -128 TB > + | | | | starting > offset of kernel mappings. > +__________________|____________|__________________|_________|___________________________________________________________ > + | > + | Kernel-space > virtual memory, shared between all processes: > +____________________________________________________________|___________________________________________________________ > + | | | | > + ffff800000000000 | -128 TB | ffff87ffffffffff | 8 TB | ... guard > hole, also reserved for hypervisor > + ffff880000000000 | -120 TB | ffffc7ffffffffff | 64 TB | direct mapping > of all physical memory (page_offset_base) > + ffffc80000000000 | -56 TB | ffffc8ffffffffff | 1 TB | ... unused hole > + ffffc90000000000 | -55 TB | ffffe8ffffffffff | 32 TB | > vmalloc/ioremap space (vmalloc_base) > + ffffe90000000000 | -23 TB | ffffe9ffffffffff | 1 TB | ... unused hole > + ffffea0000000000 | -22 TB | ffffeaffffffffff | 1 TB | virtual memory > map (vmemmap_base) > + ffffeb0000000000 | -21 TB | ffffebffffffffff | 1 TB | ... unused hole > + ffffec0000000000 | -20 TB | fffffbffffffffff | 16 TB | KASAN shadow > memory > + fffffc0000000000 | -4 TB | fffffdffffffffff | 2 TB | ... unused hole > + | | | | vaddr_end for > KASLR > + fffffe0000000000 | -2 TB | fffffe7fffffffff | 0.5 TB | cpu_entry_area > mapping > + fffffe8000000000 | -1.5 TB | fffffeffffffffff | 0.5 TB | LDT remap for > PTI > + ffffff0000000000 | -1 TB | ffffff7fffffffff | 0.5 TB | %esp fixup > stacks > +__________________|____________|__________________|_________|____________________________________________________________ > + | > + | Identical > layout to the 47-bit one from here on: > +____________________________________________________________|____________________________________________________________ > + | | | | > + ffffff8000000000 | -512 GB | ffffffeeffffffff | 444 GB | ... unused hole > + ffffffef00000000 | -68 GB | fffffffeffffffff | 64 GB | EFI region > mapping space > + ffffffff00000000 | -4 GB | ffffffff7fffffff | 2 GB | ... unused hole > + ffffffff80000000 | -2 GB | ffffffff9fffffff | 512 MB | kernel text > mapping, mapped to physical address 0 > + ffffffff80000000 |-2048 MB | | | > + ffffffffa0000000 |-1536 MB | fffffffffeffffff | 1520 MB | module mapping > space > + ffffffffff000000 | -16 MB | | | > + FIXADDR_START | ~-11 MB | ffffffffff5fffff | ~0.5 MB | > kernel-internal fixmap range, variable size and offset > + ffffffffff600000 | -10 MB | ffffffffff600fff | 4 kB | legacy > vsyscall ABI > + ffffffffffe00000 | -2 MB | ffffffffffffffff | 2 MB | ... unused hole > +__________________|____________|__________________|_________|___________________________________________________________ > + > + > +==================================================== > +Complete virtual memory map with 5-level page tables > +==================================================== > + > +Notes: > + > + - With 56-bit addresses, user-space memory gets expanded by a factor of > 512x, > + from 0.125 PB to 64 PB. All kernel mappings shift down to the -64 PT > starting > + offset and many of the regions expand to support the much larger physical > + memory supported. > + > +======================================================================================================================== > + Start addr | Offset | End addr | Size | VM area > description > +======================================================================================================================== > + | | | | > + 0000000000000000 | 0 | 00ffffffffffffff | 64 PB | user-space > virtual memory, different per mm > +__________________|____________|__________________|_________|___________________________________________________________ > + | | | | > + 0000800000000000 | +64 PB | ffff7fffffffffff | ~16K PB | ... huge, > still almost 64 bits wide hole of non-canonical > + | | | | virtual > memory addresses up to the -128 TB > + | | | | starting > offset of kernel mappings. > +__________________|____________|__________________|_________|___________________________________________________________ > + | > + | Kernel-space > virtual memory, shared between all processes: > +____________________________________________________________|___________________________________________________________ > + | | | | > + ff00000000000000 | -64 PB | ff0fffffffffffff | 4 PB | ... guard > hole, also reserved for hypervisor > + ff10000000000000 | -60 PB | ff8fffffffffffff | 32 PB | direct mapping > of all physical memory (page_offset_base) > + ff90000000000000 | -28 PB | ff9fffffffffffff | 4 PB | LDT remap for > PTI > + ffa0000000000000 | -24 PB | ffd1ffffffffffff | 12.5 PB | > vmalloc/ioremap space (vmalloc_base) > + ffd2000000000000 | -11.5 PB | ffd3ffffffffffff | 0.5 PB | ... unused hole > + ffd4000000000000 | -11 PB | ffd5ffffffffffff | 0.5 PB | virtual memory > map (vmemmap_base) > + ffd6000000000000 | -10.5 PB | ffdeffffffffffff | 2.25 PB | ... unused hole > + ffdf000000000000 | -8.25 PB | fffffdffffffffff | ~8 PB | KASAN shadow > memory > + fffffc0000000000 | -4 TB | fffffdffffffffff | 2 TB | ... unused hole > + | | | | vaddr_end for > KASLR > + fffffe0000000000 | -2 TB | fffffe7fffffffff | 0.5 TB | cpu_entry_area > mapping > + fffffe8000000000 | -1.5 TB | fffffeffffffffff | 0.5 TB | ... unused hole > + ffffff0000000000 | -1 TB | ffffff7fffffffff | 0.5 TB | %esp fixup > stacks > +__________________|____________|__________________|_________|____________________________________________________________ > + | > + | Identical > layout to the 47-bit one from here on: > +____________________________________________________________|____________________________________________________________ > + | | | | > + ffffff8000000000 | -512 GB | ffffffeeffffffff | 444 GB | ... unused hole > + ffffffef00000000 | -68 GB | fffffffeffffffff | 64 GB | EFI region > mapping space > + ffffffff00000000 | -4 GB | ffffffff7fffffff | 2 GB | ... unused hole > + ffffffff80000000 | -2 GB | ffffffff9fffffff | 512 MB | kernel text > mapping, mapped to physical address 0 > + ffffffff80000000 |-2048 MB | | | > + ffffffffa0000000 |-1536 MB | fffffffffeffffff | 1520 MB | module mapping > space > + ffffffffff000000 | -16 MB | | | > + FIXADDR_START | ~-11 MB | ffffffffff5fffff | ~0.5 MB | > kernel-internal fixmap range, variable size and offset > + ffffffffff600000 | -10 MB | ffffffffff600fff | 4 kB | legacy > vsyscall ABI > + ffffffffffe00000 | -2 MB | ffffffffffffffff | 2 MB | ... unused hole > +__________________|____________|__________________|_________|___________________________________________________________ > > Architecture defines a 64-bit virtual address. Implementations can support > less. Currently supported are 48- and 57-bit virtual addresses. Bits 63
