linux-kernel - Re: [PATCH 4/4] Enabling Access bit when doing memory swapping

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

Message-ID: <4FBA1D73.2030600@redhat.com>
Date:	Mon, 21 May 2012 13:48:19 +0300
From:	Avi Kivity <avi@...hat.com>
To:	"Hao, Xudong" <xudong.hao@...el.com>
CC:	Marcelo Tosatti <mtosatti@...hat.com>,
	Xudong Hao <xudong.hao@...ux.intel.com>,
	"kvm@...r.kernel.org" <kvm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"Shan, Haitao" <haitao.shan@...el.com>,
	"Zhang, Xiantao" <xiantao.zhang@...el.com>
Subject: Re: [PATCH 4/4] Enabling Access bit when doing memory swapping

On 05/21/2012 01:35 PM, Hao, Xudong wrote:
> > 
> > That doesn't answer the question.  An atomic operation is now non-atomic.
> > 
> > You can calculate shadow_accessed_bit and keep on using clear_bit(), or
> > switch to cmpxchg64(), but don't just drop the dirty bit here.
> > 
>
> I know your meaning. How about this changes:
>
> ...
>             young = 1;
> +            if (enable_ept_ad_bits)
> +                clear_bit(ffs(shadow_accessed_mask), (unsigned long *)spte);

ffs() returns an off-by-one result, so this needs to be adjusted.  IIRC
bsfl is slow, but this shouldn't be a problem here.


-- 
error compiling committee.c: too many arguments to function

--
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/