linux-kernel - Re: [PATCH v2 8/10] KVM: MMU: prefetch ptes when intercepted guest #PF

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Wed, 30 Jun 2010 08:58:22 +0800
From:	Xiao Guangrong <xiaoguangrong@...fujitsu.com>
To:	Marcelo Tosatti <mtosatti@...hat.com>
CC:	Avi Kivity <avi@...hat.com>, LKML <linux-kernel@...r.kernel.org>,
	KVM list <kvm@...r.kernel.org>
Subject: Re: [PATCH v2 8/10] KVM: MMU: prefetch ptes when intercepted guest
 #PF



Marcelo Tosatti wrote:

>>> Also prefetch should be disabled for EPT, due to lack of accessed bit.
>>>
>> But we call mmu_set_spte() with speculative == false, it not touch the accessed bit.
> 
> There is no accessed bit on EPT. So the aging code (kvm_age_rmapp)
> considers any present translation as accessed. There is no way to
> distinguish between actually accessed translations and prefetched (but
> unused) ones.
> 

You are right, i'll disable the prefetch for EPT in the next version, thanks for
you point it out.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/