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Re: [PATCH 2/4] KVM: SVM: use NPT page attributes

From Andy Lutomirski <luto@kernel.org>
Newsgroups linux.kernel
Subject Re: [PATCH 2/4] KVM: SVM: use NPT page attributes
Date 2015-07-17 02:40 +0200
Message-ID <pN1QZ-6aW-9@gated-at.bofh.it> (permalink)
References <pJBq1-6gd-7@gated-at.bofh.it> <pJBq1-6gd-5@gated-at.bofh.it>
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On 07/07/2015 06:45 AM, Paolo Bonzini wrote:
> Right now, NPT page attributes are not used, and the final page
> attribute depends solely on gPAT (which however is not synced
> correctly), the guest MTRRs and the guest page attributes.
>
> However, we can do better by mimicking what is done for VMX.
> In the absence of PCI passthrough, the guest PAT can be ignored
> and the page attributes can be just WB.  If passthrough is being
> used, instead, keep respecting the guest PAT, and emulate the guest
> MTRRs through the PAT field of the nested page tables.
>
> The only snag is that WP memory cannot be emulated correctly,
> because Linux's default PAT setting only includes the other types.
>

As of quite recently, Linux understands that the PAT has eight slots, 
and we can probably give you WP.  Do you want it?

--Andy
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Re: [PATCH 2/4] KVM: SVM: use NPT page attributes Andy Lutomirski <luto@kernel.org> - 2015-07-17 02:40 +0200

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