Date: Sat, 16 May 2015 11:36:14 -0700 From: John-Mark Gurney <jmg@funkthat.com> To: Allan Jude <allanjude@freebsd.org> Cc: virtualization@freebsd.org, "George V. Neville-Neil" <gnn@freebsd.org> Subject: Re: bhyve code question, pci_virtio_net.c Message-ID: <20150516183614.GL37063@funkthat.com> In-Reply-To: <55577814.6040202@freebsd.org> References: <55577814.6040202@freebsd.org>
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Allan Jude wrote this message on Sat, May 16, 2015 at 13:02 -0400:
> While looking at the code, I noticed the following comment:
>
> /*
> * The default MAC address is the standard NetApp OUI of 00-a0-98,
> * followed by an MD5 of the PCI slot/func number and dev name
> */
> if (!mac_provided) {
> snprintf(nstr, sizeof(nstr), "%d-%d-%s", pi->pi_slot,
> pi->pi_func, vmname);
>
>
> which raised 2 questions:
> 1) According to the comment, the mac address should be based on the md5
> of the DEVICE name, not the VM name. Which is correct? Which is more
> desirable?
>
> I suppose most people's VMs will have similar slot/func numbers for the
> NIC (especially with certain config engines that always assign devices
> in a specific order), and so the VM name is more likely to be unique
> than the name of the tap device.
Correct, VM name makes the most sense here...
> Would it make sense to include more unique information in this hash?
> like the host's UUID or something, to prevent the chance of more than 1
> VM on the same LAN having the same MAC if they have the same VM Name?
Sure...
> 2) Should bhyve instead use the FreeBSD assigned OUI for these MAC
> addresses?
Depends, if NetApp gave us permission to use them here, then we might
as well keep using them. gnn would be the persion to talk to about
this..
--
John-Mark Gurney Voice: +1 415 225 5579
"All that I will do, has been done, All that I have, has not."
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