From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dominik Dingel , Cornelia Huck Subject: [PATCH 3.12 068/133] KVM: s390: ioeventfd: ignore leftmost bits Date: Tue, 4 Feb 2014 13:07:49 -0800 Message-Id: <20140204210738.950099300@linuxfoundation.org> In-Reply-To: <20140204210737.008598235@linuxfoundation.org> References: <20140204210737.008598235@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dominik Dingel 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 --- arch/s390/kvm/diag.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/s390/kvm/diag.c +++ b/arch/s390/kvm/diag.c @@ -122,7 +122,7 @@ static int __diag_virtio_hypercall(struc * - 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);