Re: [virtio-comment] Re: [PATCH v1 3/8] device-context: Define the device context fields for device migration

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Oct 13, 2023 at 05:44:27PM +0800, Zhu, Lingshan wrote:
> > As Michael said, software based nesting is used..
> > See if actual hw based devices can implement it or not. Many components of cpu cannot do N level nesting either, but may be virtio can.
> > I donât know how yet.
> two facts:
> 1. virito works for nested for years
> 2. your admin vq lm solution does not work for nested

First virtio works but nested migration doesn't: the way virtio works doesn't
allow L1 hypervisor to migrate L2 if it passes virtio through to L2,
except by using full emulation approaches such as shadow vq -
surely, these are still possible.

Second doesn't work is an overstatement.  It remains to be seen what else can
be done though.  You hinted at a depdenency on PASID.  Have owner be a
PASID and Parav's approach seems to work with little to no change.

-- 
MST