Hi Feng,
On Sat, Dec 19, 2020 at 12:51:03AM +0800, Chen Feng wrote:
Hi all,
I have a similar but different question here :)
Why not the tf-a support both smpd and tspd.
I am assuming you meant SPD and not TSPD.
Since the vendor's teeos that has not support ff-a interface currently.
If the teeos does not support FF-A then there is no need to include support for the SPMD. Things work as they do with the SPD.
So, I am not sure why you are looking for coexistence of both SPD and SPMD. Could you please clarify?
With armv8.4-sel2, is there a choice to disable scr.eel2 with origin vendor's theeos IDs, and enable scr.eel2 with new ff-a services?
Yes. SW does not have to use S-EL2 even if the HW supports it.
BTW, the FF-A specification is not tied to the availability of S-EL2.
It can be used by a teeos both with and without S-EL2. In either case,
- The Normal world uses a standard SMC interface to talk to the teeos.
- The Hypervisor in EL2 does not have to include a teeos specific driver. It uses a FF-A driver instead, which works with any teeos that uses FF-A.
- TF-A does not have to include teeos specific dispatcher (SPD) in EL3. It uses the SPMD instead which works with any teeos that uses FF-A.
It seems to need some tlb maintenance, but it seems work.
I do not understand the need for tlb maintenance if you want to use a teeos without FF-A. But, I might be not understanding you. Could you please clarify?
cheers, Achin
On 2020/11/23 3:27 下午, Achin Gupta via TF-A wrote:
Hi Heyi,
Happy to discuss the detail but the short answer is no.
Instead, it is possible to run an MM partition in S-EL0 under the TEE. This work is being done with OP-TEE.
From a SW architecture standpoint, it did not seem like a good idea to let EL3 run its "application" i.e. MM SP alongside a TEE which also runs its own applications. It is better to let the TEE own S-EL1 and run all applications in S-EL0 under it.
Cheers, Achin
On 23/11/2020, 05:36, "TF-A on behalf of Heyi Guo via TF-A" <tf-a-bounces@lists.trustedfirmware.org on behalf of tf-a@lists.trustedfirmware.org> wrote:
Hi All, On some platforms there may be requirements to run both TEE and SPM_MM instances, such as providing TEE services on server platforms. Do TF-A support this scenario? If it doesn't, do it make sense to add such support? Thanks, Heyi -- TF-A mailing list TF-A@lists.trustedfirmware.org https://lists.trustedfirmware.org/mailman/listinfo/tf-a-- cheers, feng