From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: "Pasi Kärkkäinen" <pasik@iki.fi>
Cc: xen-devel@lists.xensource.com
Subject: Re: Intel Xeon E5620 CPU and VT-d (IOMMU) support?
Date: Wed, 2 Jun 2010 14:02:58 -0400 [thread overview]
Message-ID: <20100602180258.GA31974@phenom.dumpdata.com> (raw)
In-Reply-To: <20100602164007.GM17817@reaktio.net>
On Wed, Jun 02, 2010 at 07:40:07PM +0300, Pasi Kärkkäinen wrote:
> Hello,
>
> I'm planning to upgrade my testbox and I was checking for hardware options.
> Can someone verify if Intel Xeon E5620 CPU supports (or doesn't support) VT-d IOMMU?
>
> I'm asking because Intel website doesn't mention VT-d for E5620:
> http://ark.intel.com/Product.aspx?id=47925
>
> .. but it does for some (older) CPUs (E5520):
> http://ark.intel.com/Product.aspx?id=40200
>
> The chipset I'm planning to get (Intel 5520 Tylersburg) does have VT-d / IOMMU support listed.
So one thing I didn't know was that you need equivalant number of DMAR
entries for the IO-APICs on your motherboard. If you have three IO-APICs (like, this
SuperMicro X8something), you need three DMAR entries - mine only has
one. Which means that VT-d is turned off (Xen and both Linux baremetal
do this) as it can't do its magic on the other IO-APICs to re-route the IRQs
to the guest. You can hack the code to re-enable it, but then you must
disable the x2APIC.
next prev parent reply other threads:[~2010-06-02 18:02 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-02 16:40 Intel Xeon E5620 CPU and VT-d (IOMMU) support? Pasi Kärkkäinen
2010-06-02 18:02 ` Konrad Rzeszutek Wilk [this message]
2010-06-03 9:33 ` Andreas Olsowski
2010-06-03 9:49 ` Pasi Kärkkäinen
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