linux-kernel - Re: [PATCH] KVM: Veirfy memory slot only for readability

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]

Date:	Sun, 04 Dec 2011 19:29:16 +0200
From:	Sasha Levin <levinsasha928@...il.com>
To:	Avi Kivity <avi@...hat.com>
Cc:	Takuya Yoshikawa <yoshikawa.takuya@....ntt.co.jp>,
	linux-kernel@...r.kernel.org,
	Marcelo Tosatti <mtosatti@...hat.com>, kvm@...r.kernel.org,
	Takuya Yoshikawa <takuya.yoshikawa@...il.com>
Subject: Re: [PATCH] KVM: Veirfy memory slot only for readability

On Sun, 2011-12-04 at 18:53 +0200, Avi Kivity wrote:
> On 12/02/2011 07:46 AM, Sasha Levin wrote:
> > > Do you want to create read only memory slots for kvm tool?
> >
> > What KVM tool currently does is copy the kernel into guest memory and
> > run it from there. An idea raised recently was instead of copying it we
> > should mmap it into the memory to reduce footprint.
> >
> > This is why I'm looking into adding a read only memory slot. The KVM
> > code doesn't have to know it's read only.
> 
> The kernel will patch itself very early.  You need to use MAP_PRIVATE
> (and thus have a read/write area).  It will be interesting to see what
> fraction of the memory is modified.
> 
> Note that mapping will remove benefits like huge page support, and that
> you can get page sharing by using ksm.  Still, it's interesting to see
> where this goes.

Why would I lose hugepage if the kernel gets it's own memory slot?

-- 

Sasha.

--
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/