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Re: [Xen-devel] [PATCH] Simplify paging_invlpg when flush is not require

To: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] Simplify paging_invlpg when flush is not required.
From: Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Date: Mon, 4 Feb 2008 11:04:54 +0000
Cc: "Tian, Kevin" <kevin.tian@xxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
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At 08:55 +0000 on 03 Feb (1202028939), Keir Fraser wrote:
> Is there a significant advantage to doing this? One other comment is that I
> don't like extra boolean 0/1 arguments to functions. I'd rather have
> something like paging_invlpg() and paging_invlpg_noflush() and only have the
> boolean argument to paging.mode->invlpg().

As someone (probably Kevin) pointed out before, the entire guest-walk
in sh_invlpg is redundant because we maintain TLB flush discipline on
shadow l2es ourselves.  Cleaning that up was on the list of things to do
when the out-of-sync shadows are done.  If we're going to change this
code now, the right thing to do is to kill off sh_invlpg entirely, except
for the call to vtlb_flush().  Then there's no need for it to return a
value at all. 



Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, Citrix Systems (R&D) Ltd.
[Company #02300071, SL9 0DZ, UK.]

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