KVM: s390: ioeventfd: ignore leftmost bits
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: 4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@vger.kernel.org
Signed-off-by: Dominik Dingel <d1e5197fc3340c52389f7f33900df40c6bf98e12@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <94980dd689360e06f79e918bf71ea5fed7a2bc63@de.ibm.com>
Signed-off-by: Cornelia Huck <94980dd689360e06f79e918bf71ea5fed7a2bc63@de.ibm.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs