linux-kernel - RE: [PATCH] KVM: x86: always set accessed bit in shadow PTEs

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Message-ID: <A9667DDFB95DB7438FA9D7D576C3D87E0AE12CC2@SHSMSX104.ccr.corp.intel.com>
Date:	Tue, 17 Nov 2015 00:59:30 +0000
From:	"Zhang, Yang Z" <yang.z.zhang@...el.com>
To:	Paolo Bonzini <pbonzini@...hat.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"kvm@...r.kernel.org" <kvm@...r.kernel.org>
CC:	Takuya Yoshikawa <yoshikawa_takuya_b1@....ntt.co.jp>
Subject: RE: [PATCH] KVM: x86: always set accessed bit in shadow PTEs

Paolo Bonzini wrote on 2015-11-13:
> Commit 7a1638ce4220 ("nEPT: Redefine EPT-specific link_shadow_page()",
> 2013-08-05) says:
> 
>     Since nEPT doesn't support A/D bit, we should not set those bit
>     when building the shadow page table.
> but this is not necessary.  Even though nEPT doesn't support A/D
> bits, and hence the vmcs12 EPT pointer will never enable them,
> we always use them for shadow page tables if available (see
> construct_eptp in vmx.c).  So we can set the A/D bits freely
> in the shadow page table.
> 
> This patch hence basically reverts commit 7a1638ce4220.
> 
> Cc: Yang Zhang <yang.z.zhang@...el.com>
> Cc: Takuya Yoshikawa <yoshikawa_takuya_b1@....ntt.co.jp>
> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>

Looks good to me.

Best regards,
Yang


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