> On 26 Jan 2021, at 11:11, Jan Beulich <jbeul...@suse.com> wrote: > > On 26.01.2021 12:06, Bertrand Marquis wrote: >>> On 26 Jan 2021, at 09:22, Jan Beulich <jbeul...@suse.com> wrote: >>> On 25.01.2021 22:27, Stefano Stabellini wrote: >>>> @@ -77,7 +77,7 @@ config SBSA_VUART_CONSOLE >>>> SBSA Generic UART implements a subset of ARM PL011 UART. >>>> >>>> config ARM_SSBD >>>> - bool "Speculative Store Bypass Disable" if EXPERT >>>> + bool "Speculative Store Bypass Disable (UNSUPPORTED)" if UNSUPPORTED >>>> depends on HAS_ALTERNATIVE >>>> default y >>>> help >>>> @@ -87,7 +87,7 @@ config ARM_SSBD >>>> If unsure, say Y. >>>> >>>> config HARDEN_BRANCH_PREDICTOR >>>> - bool "Harden the branch predictor against aliasing attacks" if EXPERT >>>> + bool "Harden the branch predictor against aliasing attacks >>>> (UNSUPPORTED)" if UNSUPPORTED >>>> default y >>>> help >>>> Speculation attacks against some high-performance processors rely on >>> >>> Both of these default to y and have their _prompt_ >>> conditional upon EXPERT. Which means only an expert can turn them >>> _off_. Which doesn't make it look like these are unsupported? Or >>> if anything, turning them off is unsupported? >> >> ...You could see that as EXPERT/UNSUPPORTED options can only be >> “modified” from their default value if EXPERT/UNSUPPORTED is activated. > > But this is nothing you can recognize when configuring Xen > (i.e. seeing just these prompts).
Maybe something we could explain more clearly in the UNSUPPORTED/EXPERT config parameters instead ? We could also make that more clear in the help of such parameters directly. I do not see how we could make that more clear directly in the prompt (as making it too long is not a good solution). > >> If this is a problem we could also change those options to be default >> to _off_ by renaming them to config DISABLE_xxxx > > Yes, this would be a possibility, albeit not necessarily > one I would like. This is not one I would like either. Bertrand > > Jan
