From ff1f3cb4b3ac5d039f02679f34cb1498d110d241 Mon Sep 17 00:00:00 2001 From: Dominik Dingel Date: Mon, 9 Dec 2013 18:30:01 +0100 Subject: [PATCH] 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 Reviewed-by: Cornelia Huck Signed-off-by: Cornelia Huck --- arch/s390/kvm/diag.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c index 5ff29be..8216c0e 100644 --- a/arch/s390/kvm/diag.c +++ b/arch/s390/kvm/diag.c @@ -121,7 +121,7 @@ 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]); -- 2.7.4