Re: [PATCH 0/4 for 2.3] vhost-user live migration support

[Yuanhan Liu <yuanhan.liu@linux.intel.com>]

On Tue, Dec 15, 2015 at 05:58:28PM +0300, Pavel Fedin wrote:
>  Hello!
> 
> > No idea. Maybe you have changed some other configures (such as of ovs)
> > without notice? Or, the ovs bridge interface resets?
> 
>  I don't touch the ovs at all. Just shut down the guest, rebuild the qemu, reinstall it, run the guest.
> 
> > 
> > BTW, would you please try my v1 patch set with above diff applied to
> > see if the ping loss is still there. You might also want to run tcpdump
> > with the dest host ovs bridge, to see if GARP is actually sent.
> 
>  Retested with wireshark running on the host. I used my qemu patch instead, but it should not matter at all:
> --- cut ---
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> index 1b6c5ac..5ca2987 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -480,7 +480,12 @@ static int vhost_user_get_u64(struct vhost_dev *dev, int request, uint64_t *u64)
> 
>  static int vhost_user_get_features(struct vhost_dev *dev, uint64_t *features)
>  {
> -    return vhost_user_get_u64(dev, VHOST_USER_GET_FEATURES, features);
> +    int ret = vhost_user_get_u64(dev, VHOST_USER_GET_FEATURES, features);
> +
> +    if (!ret) {
> +        virtio_add_feature(features, VIRTIO_NET_F_GUEST_ANNOUNCE);
> +    }
> +    return ret;
>  }
> 
>  static int vhost_user_set_owner(struct vhost_dev *dev)
> --- cut ---
> 
>  So, here are both wireshark captures on the host side:

Pavel,

I can reproduce your issue on my side with above patch (and only when
F_GUEST_ANNOUNCE is not set at DPDK vhost lib). TBH, I don't know
why that happened, the cause could be subtle, and I don't think it's
worthwhile to dig it, especially it's not the right way to do it.

So, would you please try to set the F_GUEST_ANNOUNCE flag on DPDK vhost
lib side, as my early diff showed and have another test?

On the other hand, I failed to find two identical server, the two closet
I found are E5-2695 and E5-2699, However, the MSI lost fatal bug still
occurred. I'm out of thoughts what could be the root cause. I'm asking
help from som KVM gurus; hopefully they could shine some lights on.
Meanwhile, I may need try to debug it.

Since you don't meet such issue, I'd hope you could have a test and
tell me how it works :)

Thanks.

	--yliu