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[PATCH] pc-bios/s390x: Pack ResetInfo struct


From: Jason J. Herne
Subject: [PATCH] pc-bios/s390x: Pack ResetInfo struct
Date: Wed, 5 Feb 2020 13:21:26 -0500

This fixes vfio-ccw when booting non-Linux operating systems. Without this
struct being packed, a few extra bytes of low core memory get overwritten when
we  assign a value to memory address 0 in jump_to_IPL_2. This is enough to
cause some non-Linux OSes of fail when booting.

The problem was introduced by:
5c6f0d5f46a77d77 "pc-bios/s390x: Fix reset psw mask".

The fix is to pack the struct thereby removing the 4 bytes of padding that get
added at the end, likely to allow an array of these structs to naturally align
on an 8-byte boundary.

Fixes: 5c6f0d5f46a7 ("pc-bios/s390x: Fix reset psw mask")
CC: Janosch Frank <address@hidden>
Signed-off-by: Jason J. Herne <address@hidden>
---
 pc-bios/s390-ccw/jump2ipl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pc-bios/s390-ccw/jump2ipl.c b/pc-bios/s390-ccw/jump2ipl.c
index da13c43cc0..1e9eaa037f 100644
--- a/pc-bios/s390-ccw/jump2ipl.c
+++ b/pc-bios/s390-ccw/jump2ipl.c
@@ -18,7 +18,7 @@
 typedef struct ResetInfo {
     uint64_t ipl_psw;
     uint32_t ipl_continue;
-} ResetInfo;
+} __attribute__((packed)) ResetInfo;
 
 static ResetInfo save;
 
-- 
2.21.1




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