On 05.11.21 18:58, Martin Roth wrote:
Oct 31, 2021, 15:03 by nico.h@gmx.de:
Hi Sheng,
On 27.10.21 06:29, Tan, Lean Sheng wrote:
As mentioned earlier the Firmware of the PSE needs to be loaded at boot time of the host CPU, this is mandatory for Elkhart Lake.
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so as far as I understand it this is not necessarily a blob, your patch only treats it like one? Or is there any need to make it proprietary?
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OTOH, if we'd add an option to load an external file like your patch suggests, we'd lose a lot. Not only, would it complicate the build process, we'd also have another platform that can't boot without external files. And that is more error-prone and always leads to more support requests, frustration etc. It's bad for the project, IMHO.
Nico
The issue of loading the PSE firmware was brought up in the coreboot leadership meeting on October 20.
Sheng mentioned that the desire/plan is to open the code for the PSE binary at some point, but it isn't open yet.
This binary is also mandatory for the elkhart lake platform, so to support this platform, loading this is required, whether it's built from source as a part of the coreboot build or supplied as a blob.
That's not true. Just rumors?
The decision at the leadership meeting was to allow this binary to be loaded by coreboot, so long as the PSE acts like an EC, and does not have access to the X86 memory space.
The discussion happened under a false pretext and with outdated information. Also, the PSE is nothing like an EC. Hint: does an EC do parts of the SoC silicon init that would usually be done by our ramstage?
Maybe to avoid wasting time with premature decisions, we should make up some guidelines? For instance, first discuss something on the mailing list, then in the leadership meeting? This way people could at least get a little information before they make decisions.
The load method wasn't discussed beyond what's in CB:55367, so if there's a different load method that's desired, that could be acceptable, but I think we can close the discussion on whether or not to allow the binary loader to be added, provided Sheng can show that this part doesn't have security implications for the X86 side.
Interesting point about the security. I'm also curious. I couldn't find anything about the mentioned MMU in Intel's docs.
Nico
PS. Please have a look at the available documentation before making decisions.