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Re: [Qemu-devel] Intermittent e1000 failure on qemu-kvm 1.0
From: |
Chris Webb |
Subject: |
Re: [Qemu-devel] Intermittent e1000 failure on qemu-kvm 1.0 |
Date: |
Fri, 20 Apr 2012 09:49:03 +0100 |
User-agent: |
Mutt/1.5.20 (2009-06-14) |
Hi. Sorry for the slow follow-up.
Stefan Hajnoczi <address@hidden> writes:
> Yes, it's odd that QEMU changes make the issue go away but tcpdump
> suggests the packet is not being sent from the bridge to the tap
> device.
Indeed. I really don't understand how to the two could possible interact!
> e1000 and rtl8139 both use the same QEMU network subsystem code. I
> don't see an obvious difference between the two.
I wondered whether it could be some sort of checksum offloading which
doesn't apply for virtio or rtl8139, but otherwise I agree it's extremely
strange.
> Since this issue only happens once in many QEMU runs are you sure that
> -usbdevice tablet really makes the issue go away?
I ran in a tight loop without it for around 500 iterations, and have done so
again to confirm. Typically it fails within 20-40 iterations with -usbdevice
tablet present.
> Are you using ebtables? I know you mentioned disabling iptables and
> it would be good to try the same for ebtables if you use it.
We're normally using ebtables, but I completely flushed all the tables and
set policy of ACCEPT for these tests to eliminate the possibility of bugs in
my table create code.
> In order to debug the host networking issue you may be able to use
> ebtables/iptables LOG targets to collect information on how far
> exactly the packets are getting. For example, you could try logging
> all packets destined for the guest MAC address - and if the log
> information includes the network interface you should see the packet
> move between its source, the bridge, and the destination interface. I
> have never tried this but it might work.
I will have a play with this.
Cheers,
Chris.
- Re: [Qemu-devel] Intermittent e1000 failure on qemu-kvm 1.0, (continued)
- Re: [Qemu-devel] Intermittent e1000 failure on qemu-kvm 1.0, Chris Webb, 2012/04/03
- Re: [Qemu-devel] Intermittent e1000 failure on qemu-kvm 1.0, Stefan Hajnoczi, 2012/04/03
- Re: [Qemu-devel] Intermittent e1000 failure on qemu-kvm 1.0, Chris Webb, 2012/04/03
- Re: [Qemu-devel] Intermittent e1000 failure on qemu-kvm 1.0, Stefan Hajnoczi, 2012/04/03
- Re: [Qemu-devel] Intermittent e1000 failure on qemu-kvm 1.0, Chris Webb, 2012/04/03
- Re: [Qemu-devel] Intermittent e1000 failure on qemu-kvm 1.0, Stefan Hajnoczi, 2012/04/03
- Re: [Qemu-devel] Intermittent e1000 failure on qemu-kvm 1.0, Chris Webb, 2012/04/03
- Re: [Qemu-devel] Intermittent e1000 failure on qemu-kvm 1.0, Stefan Hajnoczi, 2012/04/11
- Re: [Qemu-devel] Intermittent e1000 failure on qemu-kvm 1.0, Chris Webb, 2012/04/12
- Re: [Qemu-devel] Intermittent e1000 failure on qemu-kvm 1.0, Stefan Hajnoczi, 2012/04/12
- Re: [Qemu-devel] Intermittent e1000 failure on qemu-kvm 1.0,
Chris Webb <=