message: clear the unneeded entries of the initial page tables
  revise debug messages
  increase the readability of the code
diff: @@ -17,7 +17,6 @@ use x86::irq::PageFaultError;
  use crate::arch::x86_64::kernel::apic;
  use crate::arch::x86_64::kernel::get_mbinfo;
  use crate::arch::x86_64::kernel::irq;
  -use crate::arch::x86_64::kernel::is_uhyve;
  use crate::arch::x86_64::kernel::processor;
  use crate::arch::x86_64::mm::physicalmem;
  use crate::arch::x86_64::mm::{paddr_to_slice, PhysAddr, VirtAddr};
  @@ -507,8 +506,8 @@ where
  // Does the table exist yet?
  if !self.entries[index].is_present() {
  // Allocate a single 4 KiB page for the new entry and mark it as a valid, writable subtable.
  - let physical_address = physicalmem::allocate(BasePageSize::SIZE).unwrap();
  - self.entries[index].set(physical_address, PageTableEntryFlags::WRITABLE);
  + let new_entry = physicalmem::allocate(BasePageSize::SIZE).unwrap();
  + self.entries[index].set(new_entry, PageTableEntryFlags::WRITABLE);
  // Mark all entries as unused in the newly created table.
  let subtable = self.subtable::<S>(page);
  @@ -678,9 +677,9 @@ pub fn map<S: PageSize>(
  flags: PageTableEntryFlags,
  ) {
  trace!(
  - "Mapping virtual address {:#X} to physical address {:#X} ({} pages)",
  - virtual_address,
  + "Mapping physical address {:#X} to virtual address {:#X} ({} pages)",
  physical_address,
  + virtual_address,
  count
  );
  @@ -734,7 +733,6 @@ pub fn init_page_tables() {
  debug!("Create new view to the kernel space");
  unsafe {
  - if !is_uhyve() {
  let pml4 = controlregs::cr3();
  let pde = pml4 + 2 * BasePageSize::SIZE as u64;
  @@ -753,7 +751,6 @@ pub fn init_page_tables() {
  // flush tlb
  controlregs::cr3_write(pml4);
  - }
  // Identity-map the supplied Multiboot information and command line.
  let mb_info = get_mbinfo();
  