From: Andy Lutomirski <luto@kernel.org>
To: Paolo Bonzini <pbonzini@redhat.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: guangrong.xiao@linux.intel.com, jroedel@suse.de,
alex.williamson@redhat.com, ogerlitz@mellanox.com,
amirv@mellanox.com
Subject: Re: [PATCH 2/4] KVM: SVM: use NPT page attributes
Date: Thu, 16 Jul 2015 17:35:28 -0700 [thread overview]
Message-ID: <55A84DD0.9040008@kernel.org> (raw)
In-Reply-To: <1436276739-50326-3-git-send-email-pbonzini@redhat.com>
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
next prev parent reply other threads:[~2015-07-17 0:35 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-07 13:45 [RFC/RFT PATCH v2 0/4] KVM: x86: full virtualization of guest MTRR Paolo Bonzini
2015-07-07 13:45 ` [PATCH 1/4] KVM: count number of assigned devices Paolo Bonzini
2015-07-07 15:22 ` Alex Williamson
2015-07-07 15:36 ` Paolo Bonzini
2015-07-07 13:45 ` [PATCH 2/4] KVM: SVM: use NPT page attributes Paolo Bonzini
2015-07-08 5:59 ` Xiao Guangrong
2015-07-08 11:19 ` Paolo Bonzini
2015-07-09 2:30 ` Xiao Guangrong
2015-07-09 15:18 ` Paolo Bonzini
2015-07-10 1:19 ` Xiao Guangrong
2015-07-10 10:47 ` Paolo Bonzini
2015-07-10 16:02 ` Xiao Guangrong
2015-07-17 0:35 ` Andy Lutomirski [this message]
2015-07-17 2:31 ` Paolo Bonzini
2015-07-07 13:45 ` [PATCH 3/4] KVM: SVM: Sync g_pat with guest-written PAT value Paolo Bonzini
2015-07-07 13:45 ` [PATCH 4/4] KVM: x86: apply guest MTRR virtualization on host reserved pages Paolo Bonzini
2015-07-07 14:06 ` [RFC/RFT PATCH v2 0/4] KVM: x86: full virtualization of guest MTRR Joerg Roedel
2015-07-07 14:09 ` Paolo Bonzini
2015-07-07 14:14 ` Joerg Roedel
-- strict thread matches above, loose matches on Subject: below --
2015-07-08 15:18 [RFC/RFT PATCH v3 " Paolo Bonzini
2015-07-08 15:18 ` [PATCH 2/4] KVM: SVM: use NPT page attributes Paolo Bonzini
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