RE: Likely bug in the PV driver v9.0

[Paul Durrant <xadimgnik@xxxxxxxxx>]

Hi Oliver,

 

  Xen 4.9 and Ubuntu 18.04 are clearly both a little old. I guess it is possible that changes in netback have caused problems. I think the next step is probably to disable all offloads (checksum and LSO) in advanced properties pane for the PV network frontend and see if the problem still exists. If that doesn’t have any effect then next would be to collect wireshark traces and look for oddities around RDP login.

 

  Cheers,

 

    Paul

 

 

From: Oliver Linden <oliver_linden@xxxxxxxxxxx>
Sent: 05 May 2020 18:38
To: paul@xxxxxxx; win-pv-devel@xxxxxxxxxxxxxxxxxxxx
Subject: Re: Likely bug in the PV driver v9.0

 

Hello Paul,

thanks a lot for your reply. I already reached out to the Xen IRC channels but didn't get a response besides the email address I've used for my initial email.

The Windows firewall settings don't have any influence on the behavior. I tested that already. But as far as I can recall I had the drivers installed on a Windows 10 1909 DomU on my old server running an upgraded ubuntu 18.04 with Xen 4.9 and xend still being active (originally server install date was Dec 2012 with ubuntu 12.04 and their Xen version).

With this setup the v9 drivers were working with RDP. Does this give you any hint/idea?

Best, Oliver

Am 05.05.20 um 15:56 schrieb Paul Durrant:

Hi Oliver,

 

  I can only think this is a checksumming issue. I can’t see how else a network driver operating no higher than L4 (for checksum/LSO) would be able to affect a very specific part of a higher level protocol. Although, one thing to watch out for… in the past I have seen Windows do things like re-enabling firewall rules when there is a change in the network stack so you might want to check that.

 

  Cheers,

 

    Paul

 

From: win-pv-devel <win-pv-devel-bounces@xxxxxxxxxxxxxxxxxxxx> On Behalf Of Oliver Linden
Sent: 04 May 2020 18:06
To: win-pv-devel@xxxxxxxxxxxxxxxxxxxx
Subject: Likely bug in the PV driver v9.0

 

Dear all,

I'm observing an annoying bug with the v9 Windows PV drivers. It's easy reproducible here on my side:

Dom0:
ubuntu 20.04 freshly installed around Easter with there version of Xen (4.11) and only using the xl tool-stack.

DomU:
With every fresh installation of Windows 10 v1909 German the following can be reproduced:

• Everything is working but slow as expected
• Installation of the v9 drivers works well without any issues and results in significantly improved speed

but

RDP connections to such a machine aren't possible anymore. The RDP service always asks for a user/PW but never accepts it. To be precise, the RDP connections are working

• with the plain vanilla installation
• with the v9 drivers being installed except the network class & driver

Since I'm using my Windows machines predominately with RDP clients it would be great if this can be solved. Please let me know if you need any kind of details from my side.

Best, Oliver