Re: Hyper-Threading Vulnerability

Tomasz Torcz
2005-05-15T14:52:43Z

On Sun, May 15, 2005 at 04:12:07PM +0200, Andi Kleen wrote:
> > > > However they've patched the FreeBSD kernel to "workaround?" it:
> > > > ftp://ftp.freebsd.org/pub/FreeBSD/CERT/patches/SA-05:09/htt5.patch
> > >
> > > That's a similar stupid idea as they did with the disk write
> > > cache (lowering the MTBFs of their disks by considerable factors,
> > > which is much worse than the power off data loss problem)
> > > Let's not go down this path please.
> >
> > What wrong did they do with disk write cache?
>
> They turned it off by default, which according to disk vendors
> lowers the MTBF of your disk to a fraction of the original value.
>
> I bet the total amount of valuable data lost for FreeBSD users because
> of broken disks is much much bigger than what they gained from not losing
> in the rather hard to hit power off cases.

Aren't I/O barriers a way to safely use write cache?

--
Tomasz Torcz "God, root, what's the difference?"
zdzichu@irc.-nie.spam-.pl "God is more forgiving."