On Mon, Sep 07, 2026 at 06:03:25PM +0200, Eric Auger wrote: > > > On 9/7/26 5:35 PM, Mostafa Saleh wrote: > > On Mon, Sep 07, 2026 at 04:49:58PM +0200, Eric Auger wrote: > >> > >> On 9/1/26 4:11 PM, Mostafa Saleh wrote: > >>> On Fri, Aug 14, 2026 at 12:25:09AM +0800, Tao Tang wrote: > >>>> To prevent aliasing between translations controlled through the Secure > >>>> and > >>>> Non-secure programming interfaces, the IOTLB lookup key must incorporate > >>>> SEC_SID. > >>>> > >>>> This commit: > >>>> - expands SMMUIOTLBKey with SEC_SID field for cache key differentiation > >>> I still feel that it's better to have a separate IOTLB for the secure > >>> world, as it should never mix with the non-secure one; as I commented > >>> on the last version: > >>> https://lore.kernel.org/qemu-devel/[email protected]/ > >>> > >>> Then all the functions can be re-used and it is just a matter > >>> of passing the right instance. > >>> > >>> No strong opinion though, this approach should work also, so it is up > >>> to Eric. > >> I don't have a strong opinion either. I am just curious about what the > >> implementation will become once we add further support for StreamWorld. > >> Will we be able to keep separate IOTLBs or will it make more sense to > >> have a unified IOTLB? > > Is that about the possiblity of mixing TLB entries accross different > > StreamWorlds, as I don't see immediately if that is possible. > > > > Or is it about growing number of IOTLB instances as we support > > StreamWorlds? I am not really sure about that as there are many > > possibilities (NS-EL1, NS-EL2, NS-EL2-E2H, Same for S, and realm) > > > > I'd imagine we have 3 instances NS, S and Realm but each one would > > need a STRW anyway, so maybe having a big one is not that bad. > Yes that was the question. Do we plan to have a multiplication of IOTLBs > for each streamworld value in which case it may become messy? > > Anyway we can rework later. So I would say pick up your prefered solution.
Let's keep it as it is now then (shared IOTLB). After more thinking I believe that would scale better. Thanks, Mostafa > > Eric >
