On Thu, Oct 22, 2009 at 10:23:44AM -0700, Shirley Ma wrote:
> On Thu, 2009-10-22 at 15:13 +0200, Michael S. Tsirkin wrote:
> > OK, I sent a patch that should fix the errors for you.
> > Could you please confirm, preferably on-list, whether
> > the patch makes the errors go away for you with
> > userspace virtio?
>
> Confirmed, your patch has fixed irq handler mismatch errors.
>
> > However, as I said previously, it's good to fix them but I think
> > they are unrelated to the fact that vhost does not work
> > for you.
>
> Yes, agreed. One observation is when I enable PCI MSI in guest kernel, I
> found that even without vhost supportin host kernel the network doesn't
> work either.
Yes, but that's on Avi's qemu-kvm.git, so probably merge problems again.
> So I think this is nothing related to vhost. I need to find
> why PCI MSI doesn't work for me.
Probably just bisect until you find the bad commit.
> > Shirley, if you have the time, please send details
> > on your setup and observations on tcpdump output
> > in both guest and host with vhost enabled.
>
> Yes, here are details:
>
> HW and distros:
> T61 laptop, cpu is
> vendor_id : GenuineIntel
> cpu family : 6
> model : 15
> model name : Intel(R) Core(TM)2 Duo CPU T7700 @ 2.40GHz
> stepping : 11
> cpu MHz : 2393.902
> cache size : 4096 KB
>
> Guest installed Fedora 10, Host installed Fedora 10 and updated to
> Fedora11, both doesn't work with guest kernel MSI enabled w/i, w/o vhost
> support.
So, IIUC, my tree with MSI without vhost works?
>
> Source trees:
> clone your qemu-kvm and vhost git. host kernel is vhost git, guest
> kernel 2.6.32-rc5
>
> Compile option:
> qemu: ./configure (default target-list = x86_64-softmmu)
> guest kernel: PCI MSI, virio enabled
> host kernel: vhost, kvm, evenfd all enabled
>
> I tried tap, raw, vnet0, eth0,
what are vnet0 and eth0?
Do you have a bridge in host?
What do brctl show and ifconfig -a show in host?
> here are some qemu commandline example:
>
> mst/qemu-kvm/x86_64-softmmu/qemu-system-x86_64
> -s /home/xma/images/fedora10-2-vm -name guest2 -boot c -M pc -m 512 -smp
> 1 -monitor pty -drive
> file=/home/xma/images/fedora10-2-vm,if=virtio,boot=on -net
> raw,ifname=eth0 -net nic,macaddr=54:52:00:46:26:80,model=virtio,vhost
>
> mst/qemu-kvm/x86_64-softmmu/qemu-system-x86_64
> -s /home/xma/images/fedora10-2-vm -name guest2 -boot c -M pc -m 512 -smp
> 1 -monitor pty -drive
> file=/home/xma/images/fedora10-2-vm,if=virtio,boot=on -net
> raw,ifname=vnet0 -net nic,model,macaddr=54:52:00:46:26:80=virtio,vhost
>
> Please let me know what I can do next. I am eager to test the vhost
> performance for both latency and bw.
> tcpdump output:
> When I ping from guest to host, I didn't see any packets from any
> interfaces, not even an arp request.
>
> When I ping from host to guest, guest interface didn't see any packets
> either, not even an arp request.
Did you try tcpdump on the tap interface in host?
> Thanks for your help!
> Shirley
>
>
>
>
Possibly we'll have to debug this in vhost in host kernel.
I would debug this directly, it's just that my setup is somehow
different and I do not see this issue, otherwise I would not
waste your time.
Can we add some printks?
handle_tx has this at the top:
if (!sock || !sock_writeable(sock->sk))
return;
Could you please add
printk(KERN_ERR "%s: !sock = %d, !sock || !sock_writeable(sock->sk) =
%d",
__func__, !sock , !sock || !sock_writeable(sock->sk));
*Before* these checks?
Then make modules modules_install
rmmod vhost_net
insmod vhost_net
and re-run.
If you want me to send a patch that does this, let me know please.
Thanks!
--
MST
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