crash/0013-xen-increase-__PHYSICA...

44 lines
1.6 KiB
Diff

From fdb41f0b6fa42a692e5fa39da3801f6ca18e8a6b Mon Sep 17 00:00:00 2001
From: Jiri Bohac <jbohac@suse.cz>
Date: Mon, 25 Jan 2021 22:44:50 +0100
Subject: [PATCH 13/13] xen: increase __PHYSICAL_MASK_SHIFT_XEN to 52
The current value of __PHYSICAL_MASK_SHIFT_XEN in crash (40) is
smaller than the kernel (52) since kernel commit 6f0e8bf167 (xen:
support 52 bit physical addresses in pv guests).
This can cause x86_64_pud_offset() to lose the most significant
bits of pgd_pte, leading to a failed xen_m2p() translation,
resulting in crash failing with an error message like this:
crash: read error: physical address: ffffffffffffffff type: "pud page"
Both Intel and AMD documentation mandate that unused physical
address bits must be 0, so there is no need to explicitly mask them
out with a mask narrower than the architecture limit of 52. This
is also confirmed by this kernel commit: b83ce5ee91.
Increase the value of __PHYSICAL_MASK_SHIFT_XEN to 52.
Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
---
defs.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/defs.h b/defs.h
index ffbe73bfb508..35cdac20420c 100644
--- a/defs.h
+++ b/defs.h
@@ -3585,7 +3585,7 @@ struct arm64_stackframe {
* PHYSICAL_PAGE_MASK changed (enlarged) between 2.4 and 2.6, so
* for safety, use the 2.6 values to generate it.
*/
-#define __PHYSICAL_MASK_SHIFT_XEN 40
+#define __PHYSICAL_MASK_SHIFT_XEN 52
#define __PHYSICAL_MASK_SHIFT_2_6 46
#define __PHYSICAL_MASK_SHIFT_5LEVEL 52
#define __PHYSICAL_MASK_SHIFT (machdep->machspec->physical_mask_shift)
--
2.17.1