On 25/09/2018 10:07, Ilias Apalodimas wrote:
Hello,
Can we add a discussion in upcoming meetings about the participation of SMMU in the booting procedure?
If I were you I'd roll up to one of the Thursday meetings. There's usually time for a bit of any other business.
In the past there's been a number of proposals on how to mitigate attacks, were a rogue PCI card is inserted into the system. Some of them include shutting down external DMA ports until the OS explicitly powers them up or blocking DMA using BME bit et > Keeping in mind this will enhance the security of devices would it make sense to include it as a 'MUST' if the hardware is present or a recommendation would be enough?
I'm not totally convinced this is in scope for EBBR (don't take this as a firm "no").
Basically EBBR primarily focuses on the handover from system firmware to OS[1].
For full defense this is essentially a requirement about the state of the system when we hand over from BL<something> to BL33 isn't it? It might therefore be regarded as an implementation quality issue.
Daniel.
[1] It is true we have contemplated (but haven't yet acted on) imposing also imposing requirements on boot ROMs but this is only really to try and squash (mis)features that impose a requirement to pre-partition the media the OS will install onto.