From: Alex Williamson <alex.williamson@redhat.com>
To: Tian Fang <tfang.ca@gmail.com>
Cc: kvm@vger.kernel.org
Subject: Re: PCI passthrough in nested kvm
Date: Fri, 06 Jan 2012 08:35:34 -0700 [thread overview]
Message-ID: <1325864134.1605.18.camel@bling.home> (raw)
In-Reply-To: <CAKi6bsq7pzwLwBGvXYmhNc_fV8Lx9CArnTdk0+5jdEAqVPjrkA@mail.gmail.com>
On Thu, 2012-01-05 at 23:50 -0500, Tian Fang wrote:
> Hi,
>
> Nested kvm is supported. Wondering if a PCI device is able to be
> passed through into the nested kvm. Could some experts share some
> insides?
No, there's no iommu exposed to the L1 guest, so there's no way to
program the iommu for the L2 guest. You would also be bouncing
interrupts from the host to the L1 guest to the L2 guest, so you could
expect a performance hit with each level you add.
Alex
prev parent reply other threads:[~2012-01-06 15:35 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-06 4:50 PCI passthrough in nested kvm Tian Fang
2012-01-06 15:35 ` Alex Williamson [this message]
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