[MODERATED] Re: [PATCH v7 04/10] TAAv7 4

On Tue, Oct 22, 2019 at 05:27:56PM -0700, speck for Pawan Gupta wrote:
> On Wed, Oct 23, 2019 at 12:05:55AM +0200, speck for Borislav Petkov wrote:
> > On Tue, Oct 22, 2019 at 11:53:21PM +0200, Borislav Petkov wrote:
> > > On Tue, Oct 22, 2019 at 02:29:02PM -0700, speck for Pawan Gupta wrote:
> > > > Side effect of RTM check ahead of X86_BUG_TAA will be a dmesg print
> > > > "Mitigation: TSX disabled" when X86_BUG_TAA is not set.
> > > 
> > > So what you're trying to tell me is that you don't want to print that
> > > message at all?
> > > 
> > > 	if (!boot_cpu_has(X86_FEATURE_RTM)) {
> > > 		taa_mitigation = TAA_MITIGATION_TSX_DISABLE;
> > > 		return;
> > > 	}
> > > 
> > > How's that?
> > 
> > And to perhaps answer your other question from below maybe - I'm
> > assuming you want something like this:
> > 
> > 	if (!boot_cpu_has(X86_FEATURE_RTM)) {
> > 		taa_mitigation = TAA_MITIGATION_TSX_DISABLE;
> > 		setup_clear_cpu_bug(X86_BUG_TAA);

I think we first need to agree on whether disabling TSX is the
mitigation for X86_BUG_TAA or the lack of bug. Your clearing the bug bit
here makes me think that you are treating it as lack of bug. This series
treats it as a mitigation when the hardware has the bug. Let me know
your thoughts on this.

Thanks,
Pawan