[Qemu-devel] [PATCH 2/2] s390x: Ignore sam31

[Alexander Graf]

The SAM31 instruction switches the memory model to 31bit. Linux uses
it on bootup, so we have to implement it. We only really model the 64bit
memory model though, so we can nop it, cross our fingers and hope for
the guest to not rely on 32bit wrap semantics.

Signed-off-by: Alexander Graf <address@hidden>
---
 target-s390x/insn-data.def | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/target-s390x/insn-data.def b/target-s390x/insn-data.def
index b42ebb6..4cc2da4 100644
--- a/target-s390x/insn-data.def
+++ b/target-s390x/insn-data.def
@@ -744,8 +744,10 @@
 /* SERVICE CALL LOGICAL PROCESSOR (PV hypercall) */
     C(0xb220, SERVC,   RRE,   Z,   r1_o, r2_o, 0, 0, servc, 0)
 /* SET ADDRESSING MODE */
+    /* We have to nop SAM31, it is used by early Linux bootup */
+    C(0x010d, SAM31,   E,     Z,   0, 0, 0, 0, 0, 0)
     /* We only do 64-bit, so accept this as a no-op.
-       Let SAM24 and SAM31 signal illegal instruction.  */
+       Let SAM24 signal illegal instruction.  */
     C(0x010e, SAM64,   E,     Z,   0, 0, 0, 0, 0, 0)
 /* SET ADDRESS SPACE CONTROL FAST */
     C(0xb279, SACF,    S,     Z,   0, a2, 0, 0, sacf, 0)
-- 
1.7.12.4