vm_alloc_memseg
error = vm_alloc_memseg(ctx, VM_SYSMEM, objsize, NULL);
error = vm_alloc_memseg(ctx, VM_HIGHMEM, ctx->highmem, NULL);
error = vm_alloc_memseg(ctx, VM_LOWMEM, ctx->lowmem, NULL);
error = vm_alloc_memseg(ctx, segid, len, name);
int vm_alloc_memseg(struct vm *vm, int ident, size_t len, bool sysmem);
error = vm_alloc_memseg(sc->vmm_vm, mseg->segid, mseg->len, sysmem);