From: Joerg Roedel <joerg.roedel@amd.com>
To: Andrew Oakley <andrew@ado.is-a-geek.net>
Cc: <iommu@lists.linux-foundation.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [git pull] IOMMU Updates for v3.7-rc1
Date: Thu, 11 Oct 2012 11:32:39 +0200 [thread overview]
Message-ID: <20121011093239.GA2619@amd.com> (raw)
In-Reply-To: <20121010230231.2fb3c3b9@ado-amd-gentoo.moore.slainvet.net>
On Wed, Oct 10, 2012 at 11:02:31PM +0100, Andrew Oakley wrote:
> On Wed, 10 Oct 2012 20:11:31 +0100
> Andrew Oakley <andrew@ado.is-a-geek.net> wrote:
> I'm not sure if the fix I've got is safe or if it's really a good idea
> to enable interrupt remapping with a broken BIOS.
Sadly it is not. Your patch works for your particular case but is not
generally applicable. There are indeed systems with 2 or more IOAPICs
and they all use different device-ids.
So, typically, there is one IOAPIC per SB, like in your case. But on
RD890 the chipset NB also includes an IOAPIC (which uses
device-id 00:00.1). This IOAPIC exists on your system too but is
disabled by the BIOS because the board does not use it.
So, in the end, device-id 00:00.1 might also be correct and the IVRS
entry could refer to the NB IOAPIC. We don't have any reliable
indication which IOAPIC is described in the IVRS table.
Cheer,
Joerg
--
AMD Operating System Research Center
Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach
General Managers: Alberto Bozzo
Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632
prev parent reply other threads:[~2012-10-11 9:32 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-05 15:23 [git pull] IOMMU Updates for v3.7-rc1 Joerg Roedel
2012-10-09 21:45 ` Andrew Oakley
2012-10-10 7:30 ` Joerg Roedel
2012-10-10 8:58 ` Andrew Oakley
2012-10-10 13:32 ` Joerg Roedel
2012-10-10 19:11 ` Andrew Oakley
2012-10-10 22:02 ` Andrew Oakley
2012-10-10 22:05 ` [PATCH] iommu/amd: Workaround wrong IOAPIC devid in IVRS andrew
2012-10-11 9:32 ` Joerg Roedel [this message]
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