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From: George Dunlap <george.dunlap@eu.citrix.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: xen-devel <xen-devel@lists.xenproject.org>,
	Eddie Dong <eddie.dong@intel.com>,
	Jun Nakajima <jun.nakajima@intel.com>, Tim Deegan <tim@xen.org>
Subject: Re: PVH and mtrr/PAT.........
Date: Fri, 22 Nov 2013 12:16:42 +0000	[thread overview]
Message-ID: <528F4B2A.1010109@eu.citrix.com> (raw)
In-Reply-To: <528F496F0200007800105BFF@nat28.tlf.novell.com>

On 22/11/13 11:09, Jan Beulich wrote:
>>>> On 22.11.13 at 11:43, George Dunlap <george.dunlap@eu.citrix.com> wrote:
>> I'm not incredibly familiar with the PAT / MTRR stuff, either from a
>> hardware level or a Xen level, so sorry if this is a dumb question. It
>> sounds like you're saying, because we have virtual MTRRs that are
>> already translated into EPT types, we should disable virtual MTRRs and
>> use PAT instead.  That doesn't make any kind of sense to me.  (I didn't
>> understand it when Jan said it either.)
> The underlying observation is that MTRRs aren't really needed -
> all they can do can be done with PAT. They pre-date PAT though,
> hence hardware vendors can't easily drop them. But in a model
> like PVH I just don't see the value of allowing their use, considering
> that this adds unnecessary complexity.

OK -- so when we move forward with the plan of "PVH mode is HVM mode 
with a couple of tweaks", you think that we should have an "enable 
virtual MTRR" flag, and disable this for PVH mode?

  -George

  reply	other threads:[~2013-11-22 12:17 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-20  2:11 PVH and mtrr/PAT Mukesh Rathor
2013-11-20  7:22 ` Xu, Dongxiao
2013-11-20  8:42 ` Jan Beulich
2013-11-20 18:12   ` George Dunlap
2013-11-20 22:24     ` Mukesh Rathor
2013-11-21 15:47       ` George Dunlap
2013-11-21 23:41         ` Mukesh Rathor
2013-11-22 10:43           ` George Dunlap
2013-11-22 11:09             ` Jan Beulich
2013-11-22 12:16               ` George Dunlap [this message]
2013-11-22 12:30                 ` Jan Beulich
2013-11-22 10:29         ` Jan Beulich
2013-12-03  7:20           ` Xu, Dongxiao
2013-12-03 13:54             ` George Dunlap
2013-11-21  2:42   ` Mukesh Rathor
2013-11-21  7:50     ` konrad wilk
2013-11-21 11:40     ` Jan Beulich
2013-11-22  0:42       ` Mukesh Rathor

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