Re: kvm-tools: can't seem to set guest_mac and KVM_GET_SUPPORTED_CPUID failed.

[Sasha Levin <levinsasha928@gmail.com>]

On Wed, 2011-11-16 at 16:42 -0800, David Evensky wrote:
> 
> There was a patch (quoted below) that changed networking at the end of September. When I
> try to set the guest_mac from the usage in the patch and an admittaly too
> brief a look at the code, the guest's mac address isn't being set. I'm using:
> 
> sudo /path/to/linux-kvm/tools/kvm/kvm run -c 1 -m 256 -k /path/to/bzImage-3.0.8 \
>    -i /path/to/initramfs-host.img --console serial -p ' console=ttyS0  ' -n tap,guest_mac=00:11:11:11:11:11
> 
> In the guest I get:
> 
> # ifconfig eth0
> eth0      Link encap:Ethernet  HWaddr 02:15:15:15:15:15  
>           inet addr:192.168.122.237  Bcast:192.168.122.255  Mask:255.255.255.0
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:24 errors:0 dropped:2 overruns:0 frame:0
>           TX packets:2 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:1000 
>           RX bytes:1874 (1.8 KiB)  TX bytes:656 (656.0 B)
> 
> which is the default.

This should be '-n mode=tap,guest_mac=00:11:11:11:11:11'

It will set the right mac:

sh-2.05b# ifconfig
eth0      Link encap:Ethernet  HWaddr 00:11:11:11:11:11
[...]

> 
> Also, when I start the guest I sometimes get the following error message:
> 
>   # kvm run -k /path/to/bzImage-3.0.8 -m 256 -c 1 --name guest-15757
> KVM_GET_SUPPORTED_CPUID failed: Argument list too long

Heh, we were talking about it couple of weeks ago, but since I couldn't
reproduce it here (it was happening to me before, but now it's gone) the
discussing died.

Could you please provide some statistics on how often it happens to you?
Also, can you try wrapping the ioctl with a 'while (1)' (theres only 1
ioctl call to KVM_GET_SUPPORTED_CPUID) and see if it would happen at
some point?

Thanks!

> I haven't seen that before.
> 
> Thanks,
> \dae
> 
> On Sat, Sep 24, 2011 at 12:17:51PM +0300, Sasha Levin wrote:
> > This patch adds support for multiple network devices. The command line syntax
> > changes to the following:
> > 
> > 	--network/-n [mode=[tap/user/none]] [guest_ip=[guest ip]] [host_ip=
> > [host_ip]] [guest_mac=[guest_mac]] [script=[script]]
> > 
> > Each of the parameters is optional, and the config defaults to a TAP based
> > networking with a random MAC.
> > ...
> 
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-- 

Sasha.