KVM: s390: ioeventfd: ignore leftmost bits
authorDominik Dingel <dingel@linux.vnet.ibm.com>
Mon, 9 Dec 2013 17:30:01 +0000 (18:30 +0100)
committerCornelia Huck <cornelia.huck@de.ibm.com>
Wed, 11 Dec 2013 18:05:41 +0000 (19:05 +0100)
commitff1f3cb4b3ac5d039f02679f34cb1498d110d241
tree35dcfbab1107a734ebd58ffd1ff5000e7c804965
parent58bc33b2b700f8524772f3fc20272da2187060c8
KVM: s390: ioeventfd: ignore leftmost bits

The diagnose 500 subcode 3 contains the 32 bit subchannel id in bits 32-63
(counting from the left). As for other I/O instructions, bits 0-31 should be
ignored and thus not be passed to kvm_io_bus_write_cookie().

This fixes a bug where the guest passed non-zero bits 0-31 which the
host tried to interpret, leading to ioeventfd notification failures.

Cc: stable@vger.kernel.org
Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
arch/s390/kvm/diag.c