Hi Oliver, On 19.09.24, 11:12, "Oliver Upton" <oliver.upton@xxxxxxxxx <mailto:oliver.upton@xxxxxxxxx>> wrote: > Hi Lilit, > +cc kvmarm mailing list, get_maintainer is your friend :) > On Wed, Sep 18, 2024 at 03:27:59PM +0000, Lilit Janpoladyan wrote: > > An example of a device that tracks accesses to stage-2 translations and will > > implement page_tracking_device interface is AWS Graviton Page Tracking Agent > > (PTA). We'll be posting code for the Graviton PTA device driver in a separate > > series of patches. > In order to actually review these patches, we need to see an > implementation of such a page tracking device. Otherwise it's hard to > tell that the interface accomplishes the right abstractions. We'll be posting driver patches in the coming weeks, they should explain device functionality. > Beyond that, I have some reservations about maintaining support for > features that cannot actually be tested outside of your own environment. I understand, we'll see how we can emulate the functionality and make interface testable. > > When ARM architectural solution (FEAT_HDBSS feature) is available, we intend to > > use it via the same interface most likely with adaptations. > Will the PTA stuff eventually get retired once you get support for FEAT_HDBSS > in hardware? We'd need to keep the interface for as long as hardware without FEAT_HDBSS but with PTA is in use, hence the attempt of generalisation. > I think the best way forward here is to implement the architecture, and > hopefully after that your legacy driver can be made to fit the > interface. The FVP implements FEAT_HDBSS, so there's some (slow) > reference hardware to test against. Thanks for the idea, we'll test with FVP, but we'd need FEAT_HDBSS documentation for that. I don't think it's available yet, is it? > This is a very interesting feature, so hopefully we can move towards > something workable. > -- > Thanks, > Oliver Thanks for the feedback, we'll be working on the discussed points, Lilit Amazon Web Services Development Center Germany GmbH Krausenstr. 38 10117 Berlin Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss Eingetragen am Amtsgericht Charlottenburg unter HRB 257764 B Sitz: Berlin Ust-ID: DE 365 538 597
