VM(9) Hyra Kernel Developer’s Manual VM(9)

NAME

vm - hyra machine independent virtual memory layer

SYNOPSIS

#include <vm/vm.h>

DESCRIPTION

The Hyra virtual memory subsystem handles various aspects of virtual memory like memory mapping, keeping track of the virtual memory context per core, etc. It is split up into two layers, the machine independent layer (that this manpage describes), and the machine dependent layer called the pmap layer.

The term ’kernel physical address’ will be used to describe physical addresses that are mapped to the higher half.

The VM_HIGHER_HALF macro points to the higher half of the virtual memory space... The mapping of kernel physical addresses to virtual addresses are done with respect to the higher half, i.e., virtual = physical + hddm (where hddm is the higher half). This cleanly reserves the lower half of the virtual address space for userspace applications.

The PHYS_TO_VIRT macro converts a kernel physical address to a higher half virtual address.

The VIRT_TO_PHYS macro converts a higher half virtual address to a kernel physical address.

AUTHORS

Ian Moffett <ian@osmora.org>

SEE ALSO

dynalloc(9) pmap(9)

Hyra Jan 12 2024 Hyra