Hi Volodymyr,
On 18/12/2018 21:11, Volodymyr Babchuk wrote:
From: Volodymyr Babchuk <vlad.babc...@gmail.com>
Some fast SMCCC calls to OP-TEE should be handled in a special way.
Capabilities exchange should be filtered out, so only caps
known to mediator are used. Also mediator disables static SHM
memory capability, because it can't share OP-TEE memory with a domain.
Only domain can share memory with OP-TEE, so it ensures that OP-TEE
supports dynamic SHM.
Basically, static SHM is a reserved memory region which is always
mapped into OP-TEE address space. It belongs to OP-TEE. Normally,
NW is allowed to access there, so it can communicate with OP-TEE.
On other hand, dynamic SHM is NW's own memory, which it can share
with OP-TEE. OP-TEE maps this memory dynamically, when it wants to
access it.
Because mediator can't share one static SHM region with all guests,
it just disables it for all.
I haven't seen an answer to my question on the previous version. For reminder:
Would it make sense to still allow the hardware domain to access static SHM?
Cheers,
--
Julien Grall
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