Re: [Qemu-devel] [PATCH v5 3/3] intel_iommu: allow UNMAP notifiers

[Peter Xu <peterx@redhat.com>]

On Wed, Sep 21, 2016 at 01:49:10PM +1000, David Gibson wrote:
> On Tue, Sep 20, 2016 at 03:28:08PM +0800, Peter Xu wrote:
> > On Tue, Sep 20, 2016 at 04:14:09PM +1000, David Gibson wrote:
> > > On Wed, Sep 14, 2016 at 04:25:48PM +0800, Peter Xu wrote:
> > > > Intel vIOMMU is still lacking of a complete IOMMU notifier mechanism.
> > > > Before that is achieved, let's open a door for vhost DMAR support, which
> > > > only requires cache invalidations (UNMAP operations).
> > > > 
> > > > Meanwhile, converting hw_error() to error_report() and exit(1), to make
> > > > the error messages clean and obvious (so no CPU registers will be
> > > > dumped).
> > > 
> > > Erm... AIUI currently the intel iommu driver doesn't do any
> > > notifications.  Surely it's only valid to allow this once you've
> > > implemented unmap side notifications.
> > 
> > Yes, I suppose vhost DMAR patches will be based upon this one. I can
> > postpone this patch until Jason wants to pick it up, but it actually
> > does not hurt if we just enable it now, anyway no one is using it.
> 
> Even so, I think it's misleading to implicitly advertise a capability
> that's not yet implemented.  Changing this warning should happen after
> or at the same time as implementing the notifications in the vIOMMU
> model.

Sure. Then I'll post v6, and I'm okay with either way to merge it. Thanks.

-- peterx