RE: [PATCH] Add log to Xenfilt DriverAddDevice

[Martin Harvey <martin.harvey@xxxxxxxxxx>]

Very well, patch will be re-worked and resubmitted.

MH.

-----Original Message-----
From: Paul Durrant <xadimgnik@xxxxxxxxx> 
Sent: 13 July 2021 09:53
To: Martin Harvey <martin.harvey@xxxxxxxxxx>; win-pv-devel@xxxxxxxxxxxxxxxxxxxx
Subject: Re: [PATCH] Add log to Xenfilt DriverAddDevice

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On 13/07/2021 09:25, Martin Harvey wrote:
> Yes, we definitely need to log all filter AddDevice calls. Here's why:
> 
> Cut a long story short, the customer likes to do all the things to a VM which 
> they normally like to do to windows machines. This includes upgrading windows 
> editions via windows update on Win10, and also in some cases, mounting the 
> ISO for a newer windows server version, and upgrading the version of windows 
> server.
> 
> These upgrade cases do some driver migration steps, which often (but not 
> always) work perfectly. Unfortunately, we've seen cases where class 
> UpperFilter registry keys go missing / don't work, such that XenFilt no 
> longer binds to ACPI/PNP0A03 (PCIBus if memory serves).
> 
> If XenFilt can't filter the appropriate devices, **Everything** breaks - 
> particularly, Plug/Unplug doesn't work right, and the machine continually 
> prompts for reboot. I can go back thru case reports and give more details if 
> required.
> 
> Tracking this down as the newbie back in early 2020 took **weeks**, where it 
> could have taken a day or so. That debug print would make debugging similar 
> cases very much easier, and it's a problem we're likely to run into again.
> 
> Please include the debug print for developers sanity.
> 

That sounds like a justification :-) Care to send a v2 of the patch with (at 
least some of) this in the commit message?

   Cheers,

     Paul

> MH.
> 
> 
> -----Original Message-----
> From: win-pv-devel <win-pv-devel-bounces@xxxxxxxxxxxxxxxxxxxx> On 
> Behalf Of Paul Durrant
> Sent: 12 July 2021 20:06
> To: win-pv-devel@xxxxxxxxxxxxxxxxxxxx
> Subject: Re: [PATCH] Add log to Xenfilt DriverAddDevice
> 
>> Log all calls to DriverAddDevice, and the type of the device if 
>> possible
> 
> Any particular reason existent logging is insufficient? I think we need more 
> justification here.
> 
>