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From: Alex Williamson <alex.williamson@redhat.com>
Date: Thu, 22 Oct 2015 07:01:01 -0600
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Subject: Re: [Qemu-devel] [RFC Patch 00/12] IXGBE: Add live migration
 support for SRIOV NIC
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: emil.s.tantilov@intel.com, kvm@vger.kernel.org, linux-pci@vger.kernel.org, qemu-devel@nongnu.org, Jesse Brandeburg <jesse.brandeburg@intel.com>, carolyn.wyborny@intel.com, "Skidmore,
	Donald C" <donald.c.skidmore@intel.com>, agraf@suse.de, matthew.vick@intel.com, intel-wired-lan@lists.osuosl.org, Jeff Kirsher <jeffrey.t.kirsher@intel.com>, yang.z.zhang@intel.com, Or Gerlitz <gerlitz.or@gmail.com>, Mitch Williams <mitch.a.williams@intel.com>, nrupal.jani@intel.com, bhelgaas@google.com, Lan Tianyu <tianyu.lan@intel.com>, Linux Netdev List <netdev@vger.kernel.org>, Shannon Nelson <shannon.nelson@intel.com>, eddie.dong@intel.com, Linux Kernel <linux-kernel@vger.kernel.org>, john.ronciak@intel.com, Paolo Bonzini <pbonzini@redhat.com>

On Thu, 2015-10-22 at 15:32 +0300, Michael S. Tsirkin wrote:
> On Wed, Oct 21, 2015 at 01:20:27PM -0600, Alex Williamson wrote:
> > The trouble here is that the VF needs to be unplugged prior to the start
> > of migration because we can't do effective dirty page tracking while the
> > device is connected and doing DMA.
> 
> That's exactly what patch 12/12 is trying to accomplish.
> 
> I do see some problems with it, but I also suggested some solutions.

I was replying to:

> So... what would you expect service down wise for the following
> solution which is zero touch and I think should work for any VF
> driver:

And then later note:

"Here it's done via an enlightened guest driver."