From: Scott Wood <scottwood@freescale.com>
To: kvm-ppc@vger.kernel.org
Subject: Re: Mapping of Shared Page in e500 Powerpc kvm
Date: Tue, 25 Oct 2011 20:38:58 +0000 [thread overview]
Message-ID: <4EA71E62.2090302@freescale.com> (raw)
In-Reply-To: <loom.20111023T153549-514@post.gmane.org>
On 10/23/2011 08:45 AM, Aashish Mittal wrote:
> Hi
>
> I'm working on powerpc e500 machine (Freescale P2020RDB machine) and
> using the paravirtualization guest support available inside kvm and wanted
> to some bookkeeping of my own on the shared page and from what i
> understood is that a single tlb entry is reserved for the shared page
> (magic page) when running the guest which is never preempted or flushed
> but when i tried printing out the dtlb misses on this shared page it show
> me a large number of dtlb misses on this shared page which means that
> this page is being preempted or flushed out in some way . Can someone pleas
> e clarify this situation if i'm understanding something wrong or is it a bug ?
What kernel are you running, and how many is "a large number"?
The magic page TLB entry will need to be reloaded if the shadow PID gets
invalidated, another guest gets scheduled on that CPU, or if something
like hugetlbfs steps on that TLB entry.
If you're running a kernel that predates shadow PID support, it will be
invalidated (along with everything else in the TLB) whenever you
schedule out or change guest execution mode .
-Scott
prev parent reply other threads:[~2011-10-25 20:38 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-23 13:45 Mapping of Shared Page in e500 Powerpc kvm Aashish Mittal
2011-10-23 15:14 ` Alexander Graf
2011-10-25 20:38 ` Scott Wood [this message]
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