From: "Roedel, Joerg" <Joerg.Roedel@amd.com>
To: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: [PATCH] KVM: MMU: Do not unconditionally read PDPTE from guest memory
Date: Fri, 29 Jul 2011 13:31:11 +0200 [thread overview]
Message-ID: <20110729113111.GL5176@amd.com> (raw)
In-Reply-To: <1311842177-9542-1-git-send-email-avi@redhat.com>
On Thu, Jul 28, 2011 at 04:36:17AM -0400, Avi Kivity wrote:
> Architecturally, PDPTEs are cached in the PDPTRs when CR3 is reloaded.
> On SVM, it is not possible to implement this, but on VMX this is possible
> and was indeed implemented until nested SVM changed this to unconditionally
> read PDPTEs dynamically. This has noticable impact when running PAE guests.
>
> Fix by changing the MMU to read PDPTRs from the cache, falling back to
> reading from memory for the nested MMU.
>
> Signed-off-by: Avi Kivity <avi@redhat.com>
Hmm, interesting. Sorry for breaking it. I tested the patch on nested
svm, it works fine.
Tested-by: Joerg Roedel <joerg.roedel@amd.com>
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next prev parent reply other threads:[~2011-07-29 11:32 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-28 8:36 [PATCH] KVM: MMU: Do not unconditionally read PDPTE from guest memory Avi Kivity
2011-07-29 11:31 ` Roedel, Joerg [this message]
2011-07-31 8:08 ` Avi Kivity
2011-08-02 9:31 ` Roedel, Joerg
2011-08-02 12:34 ` Avi Kivity
2011-08-02 13:11 ` Roedel, Joerg
2011-08-04 9:49 ` Roedel, Joerg
2011-08-05 15:14 ` Marcelo Tosatti
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