On Wed, Jun 08, 2022 at 08:28:03AM +0000, Tian, Kevin wrote:
> > From: Nicolin Chen
> > Sent: Monday, June 6, 2022 2:19 PM
> > 
> > From: Jason Gunthorpe <j...@nvidia.com>
> > 
> > The KVM mechanism for controlling wbinvd is only triggered during
> > kvm_vfio_group_add(), meaning it is a one-shot test done once the devices
> > are setup.
> It's not one-shot. kvm_vfio_update_coherency() is called in both
> group_add() and group_del(). Then the coherency property is
> checked dynamically in wbinvd emulation:

>From the perspective of managing the domains that is still
one-shot. It doesn't get updated when individual devices are
added/removed to domains.

> given that I'm fine with the change in this patch. Even more probably
> we really want an explicit one-shot model so KVM can lock down
> the property once it starts to consume it then further adding a new
> group which would change the coherency is explicitly rejected and
> removing an existing group leaves it intact.

Why? Once wbinvd is enabled it is compatible with all domain
configurations, so just leave it on and ignore everything at that

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