Re: possible bug: VM drops incoming network packets (tap)

[Jim Paris <jim-XrPbb/hENzg@public.gmane.org>]

Joris wrote:
> I have a Debian unstable 64bit host on an intel S3000 quad core xeon
> X3210. Kernel 2.6.22-2-amd64 (debian flavour) KVM46.
> My guests are debian32 with 1 cpu and 1GB ram, connected via '-net
> nic,macaddr=52:54:00:00:00:xx -net tap' and linux bridging. I'm
> running 3 guests at the time.
> 
> 
> Sometimes (see below) the machine appears to drop all incoming packets
> from the network.

Hi Joris,

I'm in the same boat -- upgraded from kvm-36 to kvm-46 and I'm seeing
identical network problems.

host: quad 64-bit 2.6.20.4
guests: 32-bit 2.6.18, 32-bit 2.6.21, 64-bit 2.6.18

No difference with -no-kvm-irqchip and with "taskset -c 1".  I haven't
had a chance to debug it much further yet, although trying a different
network card might be my next step.  I was also (reluctantly) going to
try rebooting the host in case unloading the kvm-36 modules left
something in a bad state.

An especially strange thing is that, before the network dies, sshing
from my desktop->host->guest has no problems (gigabit lan from
desktop->host).  But connecting directly desktop->guest leads to
frequent short delays and noticable lag when typing.  Since that just
seems weird I was going to try to figure that part out before I
reported this to the list :)

-jim

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