Re: No IOMMU/DMAR with DELL 3020

From: Kevin Oberman <rkoberman_at_gmail.com>
Date: Thu, 9 Apr 2015 14:00:11 -0700
On Thu, Apr 9, 2015 at 3:50 AM, Slawa Olhovchenkov <slw_at_zxy.spb.ru> wrote:

> On Thu, Apr 09, 2015 at 01:03:35PM +0300, Konstantin Belousov wrote:
>
> > On Thu, Apr 09, 2015 at 11:52:33AM +0300, Slawa Olhovchenkov wrote:
> > > On Thu, Apr 09, 2015 at 11:35:12AM +0300, Konstantin Belousov wrote:
> > >
> > > > On Thu, Apr 09, 2015 at 10:28:10AM +0200, Gustau P?rez wrote:
> > > > >    Yup, sorry for the error. I checked the micro in the ark and it
> has vt-d:
> > > > >
> > > > >               http://goo.gl/CZZRHz
> > > > It only indicates that the CPU/northbridge has the hardware, but
> BIOS must
> > > > do a work to configure it and to inform the OS about the
> configuration.
> > > > Your BIOS did not.
> > > >
> > > > >
> > > > >    in the bios, there's only one option to enable virtualization
> > > > > support, which is ticked.
> > > > >
> > > > >    The complete log is here:
> > > > >
> > > > >              http://dpaste.com/28FDMJQ
> > > > >
> > > > Dmesg would not give you any useful information there. A DMAR table
> > > > is either present, or is it not. In the later case, OS cannot use the
> > > > hardware, and if no option in BIOS is present, your only choice is to
> > > > complain to the machine/BIOS vendor.
> > >
> > > May be some OS utilites can do same work?
> > > This is theoretically capable?
> >
> > No, OS must know the peculiarities of the particular chipset.  But also,
>
> Someone may be know this and wrote support in utility.
> May be chipset datashit available.
> I am don't talk about 'universal, out of box support in OS'.
> I am talk about theoretically utility, that perform some operations
> after OS load.
>
> Also, I am interesting by OS-control interleaving memory (in
> multi-socket configuration).
> This is totaly imposible or just very complex?
>

I have a system where it is enabled via some BIOS setting that does not
make it remotely obvious what it enables VT-d. I've had to ind it three
times, once when the system was new, once when I had to send it in for
warranty repair and they reset BIOS, and again when the CMOS battery had to
be replaced. Every time it took me a while to figure out the magic, but it
was there. (No, mine was not a Dell. It was a ZT systems.)
--
Kevin Oberman, Network Engineer, Retired
E-mail: rkoberman_at_gmail.com
Received on Thu Apr 09 2015 - 19:00:12 UTC

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