We have done more research and found out that the same problem as we have is faced by virtualization software running under Linux. I have found a discussion about a feature called "secondary unicast address" that would allow registering multiple MAC addresses with a NIC. Here is a discussion that explains why this is useful for virtualization: http://thread.gmane.org/gmane.linux.network/64719/focus=64775 I have been looking at the l2 qeth driver and found out that the code seems to support secondary unicast MAC addresses. Adding a secondary unicast address to a NIC can actually be done from user mode, here is a code snippet that registers a secondary MAC via a raw packet interface:
s = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL)); ... struct packet_mreq mreq; memset(&mreq, 0, sizeof(mreq)); mreq.mr_ifindex=ifr.ifr_ifindex; mreq.mr_type=PACKET_MR_UNICAST; mreq.mr_alen=ETHER_ADDR_LEN; memcpy(mreq.mr_address,mac,ETHER_ADDR_LEN); ret = setsockopt(s, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq)); The dbf trace shows that the l2 qeth driver code gets exercised and leads to a command called IPA_CMD_SETVMAC. The user mode call succeeds but I have found this error message in /sys/kernel/debug/s390dbf/qeth_msg/sprintf 00 01393420032:989799 2 - 00 000003c00092471e IPA: setvmac(x21) for 0.0.a100/eth7 returned x200C "L2 mac not authorized by hypervisor" This is where we are stuck again. Is the secondary unicast address what I think it is? Are there any restrictions on in what situations secondary MAC addresses can be added to a virtual NIC? Tomas ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
