Messages in this thread | | | Subject | Re: [RFC Part2 PATCH v3 02/26] crypto: ccp: Add Platform Security Processor (PSP) device support | From | Brijesh Singh <> | Date | Fri, 8 Sep 2017 08:54:17 -0500 |
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On 09/08/2017 03:40 AM, Borislav Petkov wrote: > On Thu, Sep 07, 2017 at 05:19:32PM -0500, Brijesh Singh wrote: >> At high level, AMD-SP (AMD Secure Processor) (i.e CCP driver) will provide the >> support for CCP, SEV and TEE FW commands. >> >> >> +--- CCP >> | >> AMD-SP --| >> | +--- SEV >> | | >> +---- PSP ---* >> | >> +---- TEE > > I still don't see the need for such finegrained separation, though. > There's no "this is a separate compilation unit because... ". At least > the PSP branch could be a single driver without the interface. > > For example, psp_request_sev_irq() is called only by sev_dev_init(). So > why is sev-dev a separate compilation unit? Is anything else going to > use the PSP interface? >
I don't know anything about the TEE support hence I don't have very strong reason for finegrained separation -- I just wanted to ensure that the SEV enablement does not interfere with TEE support in the future.
> If not, just put it all in a psp-dev file and that's it. We have a > gazillion config options and having two more just because, is not a good > reason. You can always carve it out later if there's real need. But if > the SEV thing can't function without the PSP thing, then you can just as > well put it inside it. > > This way you can save yourself a bunch of exported functions and the > like. > > Another example for not optimal design is psp_request_tee_irq() - it > doesn't really request an irq by calling into the IRQ core but simply > assigns a handler. Which looks to me like you're simulating an interface > where one is not really needed. Ditto for the sev_irq version, btw. >
It's possible that both TEE and SEV share the same interrupt but their interrupt handling approach could be totally different hence I tried to abstract it.
I am making several assumption on TEE side without knowing in detail ;)
I can go with your recommendation -- we can always crave it out later once the TEE support is visible.
-Brijesh
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