From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Campbell <ian.campbell@citrix.com>
Subject: Re: [PATCH v11 6/9] xen: Add ring 3 vmware_port support
Date: Fri, 5 Jun 2015 11:54:02 +0100
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To: Jan Beulich <JBeulich@suse.com>
Cc: Jun Nakajima <jun.nakajima@intel.com>, Tim Deegan <tim@xen.org>, Kevin Tian <kevin.tian@intel.com>, Keir Fraser <keir@xen.org>, Eddie Dong <eddie.dong@intel.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, George Dunlap <george.dunlap@eu.citrix.com>, Andrew Cooper <andrew.cooper3@citrix.com>, Ian Jackson <ian.jackson@eu.citrix.com>, Don Slutz <don.slutz@gmail.com>, Don Slutz <dslutz@verizon.com>, xen-devel@lists.xen.org, Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>, Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>, BorisOstrovsky <boris.ostrovsky@oracle.com>
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On Fri, 2015-06-05 at 10:31 +0100, Jan Beulich wrote:
> > I'm talking about cost-benefits analysis.  What's the benefit of
> > accepting this patch, and is it worth the cost?
> 
> The basic idea of allowing guests originally having got installed on
> VMware to continue their lives on Xen is certainly something worth
> accepting some cost. It's really hard to judge whether in the case
> here things go too far (and that would equally apply to the hand
> crafted instruction decoding done in earlier versions of this series).

I can see the benefit in having a guest which was installed on vmware be
able to boot and work on Xen.

But AIUI this userspace vmware port thing is not needed for that basic
use case but instead goes farther and enables advanced features like
clip boards integration, which TBH I think we could consider living
without (especially considering the costs discussed here).

It would be really useful to see a comprehensive list of exactly what
guest ring3 access to the vmware port actually enables i.e. a list of
specific features which require it.

Ian.