Re: [Qemu-arm] [PATCH v2 00/13] iommu: support txattrs, support TCG execution, implement TZ MPC

[Peter Maydell]

On 5 June 2018 at 08:39, Peter Xu <address@hidden> wrote:
> On Mon, Jun 04, 2018 at 04:29:28PM +0100, Peter Maydell wrote:
>> Hi; this is v2 of my iommu patchset, which does:
>>  * support IOMMUs that are aware of memory transaction attributes and
>>    may generate different translations for different attributes
>>  * support TCG execution out of memory which is behind an IOMMU
>>  * implement the Arm TrustZone Memory Protection Controller
>>    (which needs both the above features in the IOMMU core code)
>>  * use the MPC in the mps2-an505 board

> It seems that this series is still using the IOMMU index way.  In case
> I missed anything... Could you elaborate a bit on why this IOMMU index
> solution is preferred comparing to the way to pass in MemTxAttrs?  Or
> was there any further discussion I missed on the topic?
>
> My last post to previous series is here:
>
> https://lists.gnu.org/archive/html/qemu-devel/2018-05/msg05702.html
>
> In that, I was still confused on why we couldn't use the existing
> MemTxAttrs directly instead of the new IOMMU index (and I explained on
> why that was prefered at least to me). I didn't see replies
> afterwards.

Broadly speaking I didn't think I had any further better
explanation than I'd already given in that thread, eg here:
https://lists.gnu.org/archive/html/qemu-devel/2018-05/msg05250.html
and here:
https://lists.gnu.org/archive/html/qemu-devel/2018-05/msg05513.html

If you want to make a specific (detailed) counterproposal of a
different API, I'm happy to look at whether that works for
the use cases I care about and whether it's a nicer way to do it.

thanks
-- PMM