x86/mm: Fix dump_pagetables with Xen PV

Commit 2ae2713 ("x86: mm: convert dump_pagetables to use
walk_page_range") broke Xen PV guests as the hypervisor reserved hole in
the memory map was not taken into account.

Fix that by starting the kernel range only at GUARD_HOLE_END_ADDR.

Fixes: 2ae2713 ("x86: mm: convert dump_pagetables to use walk_page_range")
Reported-by: Julien Grall <[email protected]>
Signed-off-by: Juergen Gross <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Julien Grall <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

Author: jgross1

arch/x86/mm/dump_pagetables.c

@@ -363,13 +363,8 @@ static void ptdump_walk_pgd_level_core(struct seq_file *m,
 {
 	const struct ptdump_range ptdump_ranges[] = {
 #ifdef CONFIG_X86_64
-
-#define normalize_addr_shift (64 - (__VIRTUAL_MASK_SHIFT + 1))
-#define normalize_addr(u) ((signed long)((u) << normalize_addr_shift) >> \
-			   normalize_addr_shift)
-
 	{0, PTRS_PER_PGD * PGD_LEVEL_MULT / 2},
-	{normalize_addr(PTRS_PER_PGD * PGD_LEVEL_MULT / 2), ~0UL},
+	{GUARD_HOLE_END_ADDR, ~0UL},
 #else
 	{0, ~0UL},
 #endif