From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paul Durrant <Paul.Durrant@citrix.com>
Subject: Re: [PATCH 3/3] tools: introduce parameter max_ranges.
Date: Wed, 20 Jan 2016 10:18:01 +0000
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To: Ian Campbell <Ian.Campbell@citrix.com>, Kevin Tian <kevin.tian@intel.com>, "Yu, Zhang" <yu.c.zhang@linux.intel.com>, Wei Liu <wei.liu2@citrix.com>
Cc: "Keir (Xen.org)" <keir@xen.org>, Andrew Cooper <Andrew.Cooper3@citrix.com>, "xen-devel@lists.xen.org" <xen-devel@lists.xen.org>, Stefano Stabellini <Stefano.Stabellini@citrix.com>, "Lv,
	Zhiyuan" <zhiyuan.lv@intel.com>, "jbeulich@suse.com" <jbeulich@suse.com>
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> -----Original Message-----
> From: Ian Campbell [mailto:ian.campbell@citrix.com]
> Sent: 20 January 2016 10:16
> To: Kevin Tian; Yu, Zhang; Wei Liu; Paul Durrant
> Cc: Keir (Xen.org); jbeulich@suse.com; Andrew Cooper; xen-
> devel@lists.xen.org; Lv, Zhiyuan; Stefano Stabellini
> Subject: Re: [Xen-devel] [PATCH 3/3] tools: introduce parameter
> max_ranges.
> 
> On Wed, 2016-01-20 at 03:58 +0000, Tian, Kevin wrote:
> > > From: Yu, Zhang [mailto:yu.c.zhang@linux.intel.com]
> > > Sent: Wednesday, January 20, 2016 11:33 AM
> > > > As a feature this write-protection has nothing to be GPU
> > > > virtualization specific.
> > > > In the future the same mediated pass-through idea used in XenGT may
> > > > be
> > > > used on other I/O devices which need to shadow some structure w/
> > > > requirement
> > > > to write-protect guest memory. So it's not good to tie this to either
> > > > XenGT
> > > > or GTT.
> > > >
> > > Thank you, Kevin.
> > > Well, if this parameter is not supposed to be xengt specific, we do not
> > > need to connect it with any xengt flag such as ."vgt=1" or "GVT-g=1".
> > > Hence the user will have to configure the max_wp_ram_ranges himself,
> > > right?
> > >
> >
> > Not always. The option can be configured manually by the user, or
> > automatically set in the code when "vgt=1" is recognized.
> 
> Is the latter approach not always sufficient? IOW, if it can be done
> automatically, why would the user need to tweak it?
>

I think latter is sufficient for now. We always have the option of adding a specific wp_ram_ranges parameter in future if there is a need.

  Paul
 
> Ian.