Re: Platform Spec Technical Feedback


atishp@...
 

On Wed, 2021-10-13 at 14:35 -0600, Aaron Durbin wrote:
Sorry. I missed the other update below.

On Wed, Oct 13, 2021 at 12:32 PM Atish Patra <atish.patra@...>
wrote:
But there is no option to not implement an APLIC or PLIC,
correct?
Why not? IMSIC on its own is certainly valid. 
Yes. Platform spec just providing all the options. Wired irqs can
only
be generated using APLIC or PLIC while MSIs through IMSIC.
That's why, platform spec provides that guidance.

If a Platform only wants rely on MSIs for everything, it is okay to
implement just IMSIC. That's why, server extension only mandates

2.1.4.2.4. MSIs, Virtual MSIs, and Wired IRQs

which states

"One, or more AIA APLIC devices are required to support wired
interrupts."

APLIC can be ignored in case there are no wired irq interrupts in
the
system.

We can certainly improve the text if it is not clear.

I think that would be helpful because, to me, it reads like wired
interrupts are required.
Sure. We will try to improve the text. Any suggestions are welcome.
Thanks again for your feedback.


--
Regards,
Atish

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