[PATCH] x86/mm: fix dump_pagetables with Xen PV

From: Juergen Gross <jgross@suse.com>
To: xen-devel@lists.xenproject.org, x86@kernel.org,
	linux-kernel@vger.kernel.org
Cc: Juergen Gross <jgross@suse.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>
Subject: [PATCH] x86/mm: fix dump_pagetables with Xen PV
Date: Fri, 21 Feb 2020 11:38:51 +0100	[thread overview]
Message-ID: <20200221103851.7855-1-jgross@suse.com> (raw)

Commit 2ae27137b2db89 ("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: 2ae27137b2db89 ("x86: mm: convert dump_pagetables to use walk_page_range")
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
---
 arch/x86/mm/dump_pagetables.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index 64229dad7eab..69309cd56fdf 100644
--- a/arch/x86/mm/dump_pagetables.c
+++ b/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
-- 
2.16.4

