ACS got added in 4.0 unconditionally, that broke older<->4.0 migration
where there was a PCIe root port.
Fix this by turning it off for 3.1 and older machines; note this
fixes compatibility for older QEMUs but breaks compatibility with 4.0
for older machine types.
machine type source qemu dest qemu
3.1 3.1 4.0 broken
3.1 3.1 4.1rc2 broken
3.1 3.1 4.1+this OK ++
3.1 4.0 4.1rc2 OK
3.1 4.0 4.1+this broken --
4.0 4.0 4.1rc2 OK
4.0 4.0 4.1+this OK
So we gain and lose; the consensus seems to be treat this as a
fix for older machine types.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20190730093719.12958-3-dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
c8557f1b48