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Date:   Tue, 8 Oct 2019 17:08:47 +0200
From:   Andrea Parri <parri.andrea@gmail.com>
To:     Dexuan Cui <decui@microsoft.com>
Cc:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
        KY Srinivasan <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Sasha Levin <sashal@kernel.org>,
        Michael Kelley <mikelley@microsoft.com>,
        vkuznets <vkuznets@redhat.com>
Subject: Re: [PATCH 0/2] Drivers: hv: vmbus: Miscellaneous improvements
Message-ID: <20191008150847.GA15276@andrea>
References: <20191007163115.26197-1-parri.andrea@gmail.com>
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On Mon, Oct 07, 2019 at 05:41:10PM +0000, Dexuan Cui wrote:
> > From: linux-hyperv-owner@vger.kernel.org
> > <linux-hyperv-owner@vger.kernel.org> On Behalf Of Andrea Parri
> > Sent: Monday, October 7, 2019 9:31 AM
> > 
> > Hi all,
> > 
> > The patchset:
> > 
> > - simplifies/refactors the VMBus negotiation code by introducing
> >   the table of VMBus protocol versions (patch 1/2),
> > 
> > - enables VMBus protocol versions 5.1 and 5.2 (patch 2/2).
> > 
> > Thanks,
> >   Andrea
> > 
> > Andrea Parri (2):
> >   Drivers: hv: vmbus: Introduce table of VMBus protocol versions
> >   Drivers: hv: vmbus: Enable VMBus protocol versions 5.1 and 5.2
> 
> Should we add a module parameter to allow the user to specify a lower
> protocol version, when the VM runs on the latest host? 
> 
> This can be useful for testing and debugging purpose: the variable
> "vmbus_proto_version" is referenced by the vmbus driver itself and
> some VSC drivers: if we always use the latest available proto version,
> some code paths can not be tested on the latest hosts. 

The idea is appealing to me (altough I made no attempt to implement/test
it yet).  What do others think about this?  Maybe can be considered as a
follow-up patch/work to this series?

Thanks,
  Andrea