Re: [PATCH v4] x86/bugs: Add a separate config for each mitigation

[Ingo Molnar]

* Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:

> On Thu, Oct 12, 2023 at 08:51:24PM +0200, Ingo Molnar wrote:
> > > Another way to avoid ifdeffery:
> > > 
> > > static enum retbleed_mitigation_cmd retbleed_cmd __ro_after_init =
> > > 	IS_ENABLED(CONFIG_MITIGATION_RETBLEED) ? RETBLEED_CMD_AUTO : RETBLEED_CMD_OFF;
> > 
> > I think we could make it a simple:
> > 
> > 	static enum retbleed_mitigation_cmd retbleed_cmd __ro_after_init = IS_ENABLED(CONFIG_MITIGATION_RETBLEED);
> > 
> > Because RETBLEED_CMD_AUTO && RETBLEED_CMD_OFF maps naturally to 1 and 0. 
> > Maybe add a comment to the enum to maintain this property in the future 
> > too.
> 
> Hm, that both obfuscates the default and makes it fragile.  The fact
> that it would need a comment to try to prevent breaking it in the future
> is a clue that maybe we shouldn't do it ;-)

Can be enforced with BUILD_BUG_ON().

Thanks,

	Ingo