From: Guenter Roeck <linux@roeck-us.net>
To: Chris Wright <chrisw@sous-sol.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
David Woodhouse <dwmw2@infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"open list:INTEL IOMMU (VT-d)" <iommu@lists.linux-foundation.org>
Subject: Re: WARNING: at drivers/iommu/dmar.c:484 warn_invalid_dmar with Intel Motherboard
Date: Thu, 11 Jul 2013 13:59:02 -0700 [thread overview]
Message-ID: <20130711205902.GB22605@roeck-us.net> (raw)
In-Reply-To: <20130711190054.GC24833@sequoia2.sous-sol.org>
On Thu, Jul 11, 2013 at 12:00:54PM -0700, Chris Wright wrote:
> * Guenter Roeck (linux@roeck-us.net) wrote:
> > On Tue, Jul 09, 2013 at 04:22:52PM -0700, Chris Wright wrote:
> > > One thing I've seen is the BIOS zeroing the base register address when
> > > VT-d is disabled in BIOS. So, Guenter, a "fix" may be simply enabling
> > > VT-d in the BIOS.
> > >
> > Ah, yes, I think I may have that disabled. I'll check it tonight.
>
> Did you find out if BIOS change fixed this?
>
No, it didn't. Enabling or disabling virtualization in the BIOS did not make
a difference. It looks like there is a bad DMAR table entry (with address 0)
in the ACPI data. In case you are interested how it looks like:
DMAR @ 0xcb3f3f90
0000: 44 4d 41 52 90 00 00 00 01 d5 49 4e 54 45 4c 20 DMAR......INTEL
0010: 44 48 38 37 52 4c 20 20 40 01 00 00 49 4e 54 4c DH87RL @...INTL
0020: 01 00 00 00 26 00 00 00 00 00 00 00 00 00 00 00 ....&...........
0030: 00 00 10 00 01 00 00 00 00 00 00 00 00 00 00 00 ................
0040: 01 00 30 00 00 00 00 00 00 b0 eb cb 00 00 00 00 ..0.............
0050: ff 9f ec cb 00 00 00 00 01 08 00 00 00 00 1d 00 ................
0060: 01 08 00 00 00 00 1a 00 01 08 00 00 00 00 14 00 ................
0070: 01 00 20 00 00 00 00 00 00 00 00 d7 00 00 00 00 .. .............
0080: ff ff 1f df 00 00 00 00 01 08 00 00 00 00 02 00 ................
Turns out the i7-4770K doesn't support VT-d, so my current understanding
is that there should be no DMAR table in the first place.
Guenter
next prev parent reply other threads:[~2013-07-11 20:59 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-09 20:24 Guenter Roeck
2013-07-09 21:05 ` Bjorn Helgaas
2013-07-09 22:31 ` Guenter Roeck
2013-07-09 23:22 ` Chris Wright
2013-07-09 23:43 ` Guenter Roeck
2013-07-10 0:05 ` Chris Wright
2013-07-10 0:18 ` Guenter Roeck
2013-07-10 0:53 ` David Woodhouse
2013-07-10 3:55 ` Guenter Roeck
2013-07-11 19:00 ` Chris Wright
2013-07-11 20:59 ` Guenter Roeck [this message]
2013-07-11 22:31 ` Chris Wright
2013-08-14 9:36 ` Joerg Roedel
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