s390/kvm: dont announce RRBM support
authorChristian Borntraeger <borntraeger@de.ibm.com>
Tue, 2 Oct 2012 14:25:38 +0000 (16:25 +0200)
committerMarcelo Tosatti <mtosatti@redhat.com>
Wed, 10 Oct 2012 22:03:38 +0000 (19:03 -0300)
commit87cac8f879a5ecd7109dbe688087e8810b3364eb
treeea3be0dddea485b4a94cd29cec719f61c60cf6e9
parent416ad65f73f8a68783c98dd734f570e4829d996b
s390/kvm: dont announce RRBM support

Newer kernels (linux-next with the transparent huge page patches)
use rrbm if the feature is announced via feature bit 66.
RRBM will cause intercepts, so KVM does not handle it right now,
causing an illegal instruction in the guest.
The  easy solution is to disable the feature bit for the guest.

This fixes bugs like:
Kernel BUG at 0000000000124c2a [verbose debug info unavailable]
illegal operation: 0001 [#1] SMP
Modules linked in: virtio_balloon virtio_net ipv6 autofs4
CPU: 0 Not tainted 3.5.4 #1
Process fmempig (pid: 659, task: 000000007b712fd0, ksp: 000000007bed3670)
Krnl PSW : 0704d00180000000 0000000000124c2a (pmdp_clear_flush_young+0x5e/0x80)
     R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:1 PM:0 EA:3
     00000000003cc000 0000000000000004 0000000000000000 0000000079800000
     0000000000040000 0000000000000000 000000007bed3918 000000007cf40000
     0000000000000001 000003fff7f00000 000003d281a94000 000000007bed383c
     000000007bed3918 00000000005ecbf8 00000000002314a6 000000007bed36e0
 Krnl Code:>0000000000124c2ab9810025          ogr     %r2,%r5
           0000000000124c2e41343000           la      %r3,0(%r4,%r3)
           0000000000124c32a716fffa           brct    %r1,124c26
           0000000000124c36b9010022           lngr    %r2,%r2
           0000000000124c3ae3d0f0800004       lg      %r13,128(%r15)
           0000000000124c40eb22003f000c       srlg    %r2,%r2,63
[ 2150.713198] Call Trace:
[ 2150.713223] ([<00000000002312c4>] page_referenced_one+0x6c/0x27c)
[ 2150.713749]  [<0000000000233812>] page_referenced+0x32a/0x410
[...]

CC: stable@vger.kernel.org
CC: Alex Graf <agraf@suse.de>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
arch/s390/kvm/kvm-s390.c