From mboxrd@z Thu Jan  1 00:00:00 1970
From: Bjorn Helgaas <bjorn.helgaas@hp.com>
Date: Fri, 03 Oct 2008 15:50:18 +0000
Subject: Re: [PATCH 0/2]Add Variable Page Size and IA64 Support in Intel IOMMU
Message-Id: <200810030950.19359.bjorn.helgaas@hp.com>
List-Id: <linux-ia64.vger.kernel.org>
References: <20081001165606.GA21279@linux-os.sc.intel.com>
In-Reply-To: <20081001165606.GA21279@linux-os.sc.intel.com>
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To: Fenghua Yu <fenghua.yu@intel.com>
Cc: "Luck, Tony" <tony.luck@intel.com>, Jesse Barnes <jbarnes@virtuousgeek.org>, David Woodhouse <dwmw2@infradead.org>, Ingo Molnar <mingo@elte.hu>, Avi Kivity <avi@redhat.com>, Stephen Rothwell <sfr@canb.auug.org.au>, Andrew Morton <akpm@linux-foundation.org>, LKML <linux-kernel@vger.kernel.org>, linux-ia64@vger.kernel.org

On Wednesday 01 October 2008 10:56:06 am Fenghua Yu wrote:
> The following two patches (Intel IOMMU generic patch and ia64 specific patch) together enable Intel IOMMU on IA64 platform. They are applied cleanly on the latest linux-next tree which contains Intel IOMMU interrupt remapping and VT-d driver KVM support code.

General comment (not ia64-related): it looks like you detect the
IOMMU using the static DMAR table.  Does the IOMMU also appear in
PCI config space or the ACPI namespace?  I expect it would, because
the fact that the DMAR table is static precludes any sort of hot-plug
to add or remove IOMMUs.

If it *is* in config space or the namespace, it would be good to
exercise that discovery path to help shake out firmware bugs.  For
example, arch/ia64/hp/common/sba_iommu.c uses acpi_bus_register_driver()
to discover HP IOMMUs.  I wouldn't hold the sba_iommu.c discovery code
(most of which I take the blame for) up as a shining example of how to
do things, but it shows the point.

Bjorn