added pagewalk test

pwndbg/commands/pagewalk.py

@@ -83,7 +83,7 @@ def pagewalk(vaddr, entry=None):
             print(M.warn(f"Exception {e} while page walking"))
             entry = 0
         if entry == 0:
-            print(M.warn("page is not mapped"))
+            print(M.warn("address is not mapped"))
             return
     virtual = base + (entry & entry_mask) + offset
     print(f"pagewalk result: {C.green(hex(virtual))} [phys: {C.yellow(hex(virtual - base))}]")

tests/qemu-tests/tests/system/test_commands_kernel.py

@@ -175,3 +175,30 @@ def test_command_buddydump():
         assert f"Order {i}" not in filter_res
     filter_res = gdb.execute("bud -p", to_string=True)
     assert "free_area" not in filter_res
+
+
+@pytest.mark.skipif(
+    pwndbg.aglib.arch.name not in ["i386", "x86-64"],
+    reason="pagewalk is only fully implemented for x86 (partially relies on cr3)",
+)
+def test_command_pagewalk():
+    address = pwndbg.aglib.kernel.kbase()
+    if address is None:
+        # no kbase? fine
+        pages = pwndbg.aglib.vmmap.get()
+        address = pages[0].start
+    res = gdb.execute(f"pagewalk {hex(address)}", to_string=True)
+    assert "PMD" in res  # Page Size is only set for PMDe or PTe
+    res = res.splitlines()[-1]
+    match = re.find(r"0x[0-9a-fA-F]{16}", res)
+    physmap_addr = int(match, 16)
+    # compare the first 0x100 bytes of the page (e.g. first kernel image page) with its physmap conterpart
+    expected = pwndbg.aglib.memory.read(address, 0x100)
+    actual = pwndbg.aglib.memory.read(physmap_addr, 0x100)
+    assert all(expected[i] == actual[i] for i in range(0x100))
+    # make sure that when using cr3 for pgd, it still works
+    res2 = gdb.execute(f"pagewalk {address} --pgd $cr3", to_string=True)
+    assert res == res2
+    # test non nonexistent address
+    res = gdb.execute("pagewalk 0", to_string=True)
+    assert res == "address is not mapped"