[ 007/221] s390/kvm: dont announce RRBM support

Greg Kroah-Hartman
2013-01-15T19:04:17Z

From: Christian Borntraeger <borntraeger@de.ibm.com>

commit 87cac8f879a5ecd7109dbe688087e8810b3364eb upstream.

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:>0000000000124c2a: b9810025 ogr %r2,%r5
0000000000124c2e: 41343000 la %r3,0(%r4,%r3)
0000000000124c32: a716fffa brct %r1,124c26
0000000000124c36: b9010022 lngr %r2,%r2
0000000000124c3a: e3d0f0800004 lg %r13,128(%r15)
0000000000124c40: eb22003f000c srlg %r2,%r2,63
[ 2150.713198] Call Trace:
[ 2150.713223] ([<00000000002312c4>] page_referenced_one+0x6c/0x27c)
[ 2150.713749] [<0000000000233812>] page_referenced+0x32a/0x410
[...]

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
CC: Alex Graf <agraf@suse.de>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/s390/kvm/kvm-s390.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -997,7 +997,7 @@ static int __init kvm_s390_init(void)
}
memcpy(facilities, S390_lowcore.stfle_fac_list, 16);
facilities[0] &= 0xff00fff3f47c0000ULL;
- facilities[1] &= 0x201c000000000000ULL;
+ facilities[1] &= 0x001c000000000000ULL;
return 0;
}