From: Dominik Dingel Date: Mon, 9 Dec 2013 17:30:01 +0000 (+0100) Subject: KVM: s390: ioeventfd: ignore leftmost bits X-Git-Tag: submit/tizen_common/20140905.094502~924 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=2bd6307cab16209fabb96feb236b808c46e2d22d;p=sdk%2Femulator%2Femulator-kernel.git KVM: s390: ioeventfd: ignore leftmost bits commit ff1f3cb4b3ac5d039f02679f34cb1498d110d241 upstream. 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. Signed-off-by: Dominik Dingel Reviewed-by: Cornelia Huck Signed-off-by: Cornelia Huck Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c index 832f35c0e909..d88e846a58f1 100644 --- a/arch/s390/kvm/diag.c +++ b/arch/s390/kvm/diag.c @@ -122,7 +122,7 @@ static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu) * - gpr 4 contains the index on the bus (optionally) */ ret = kvm_io_bus_write_cookie(vcpu->kvm, KVM_VIRTIO_CCW_NOTIFY_BUS, - vcpu->run->s.regs.gprs[2], + vcpu->run->s.regs.gprs[2] & 0xffffffff, 8, &vcpu->run->s.regs.gprs[3], vcpu->run->s.regs.gprs[4]); srcu_read_unlock(&vcpu->kvm->srcu, idx);