Module kspace

Kernel memory space management.

The kernel memory space is currently managed as follows, if the address width is 48 bits (with 47 bits kernel space).

TODO: the cap of linear mapping (the start of vm alloc) are raised to workaround for high IO in TDX. We need actual vm alloc API to have a proper fix.

+-+ <- the highest used address (0xffff_ffff_ffff_0000)
| |         For the kernel code, 1 GiB.
+-+ <- 0xffff_ffff_8000_0000
| |
| |         Unused hole.
+-+ <- 0xffff_e100_0000_0000
| |         For frame metadata, 1 TiB.
+-+ <- 0xffff_e000_0000_0000
| |         For [`KVirtArea`], 32 TiB.
+-+ <- the middle of the higher half (0xffff_c000_0000_0000)
| |
| |
| |
| |         For linear mappings, 64 TiB.
| |         Mapped physical addresses are untracked.
| |
| |
| |
+-+ <- the base of high canonical address (0xffff_8000_0000_0000)

If the address width is (according to crate::arch::mm::PagingConsts) 39 bits or 57 bits, the memory space just adjust proportionally.

Modules

kvirt_area 🔒

Kernel virtual memory allocation

Structs

KernelPtConfig 🔒

Enums

MappedItem 🔒

Constants

ADDR_WIDTH_SHIFT 🔒

The shortest supported address width is 39 bits. And the literal values are written for 48 bits address width. Adjust the values by arithmetic left shift.

FRAME_METADATA_BASE_VADDR 🔒

FRAME_METADATA_CAP_VADDR 🔒

FRAME_METADATA_RANGE 🔒

KERNEL_BASE_VADDR

Start of the kernel address space. This is the lowest address of the x86-64’s high canonical addresses.

KERNEL_CODE_BASE_VADDR 🔒

KERNEL_END_VADDR

End of the kernel address space (non inclusive).

LINEAR_MAPPING_BASE_VADDR

The base address of the linear mapping of all physical memory in the kernel address space.

LINEAR_MAPPING_VADDR_RANGE

VMALLOC_BASE_VADDR 🔒

VMALLOC_VADDR_RANGE

Statics

KERNEL_PAGE_TABLE

The kernel page table instance.

Functions

activate_kernel_page_table^⚠

Activates the kernel page table.

init_kernel_page_table

Initializes the kernel page table.

kernel_loaded_offset

The kernel code is linear mapped to this address.

paddr_to_vaddr

Convert physical address to virtual address using offset, only available inside ostd