Messages in this thread | | | Date | Wed, 24 Aug 2022 21:27:55 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH v3 1/5] x86/microcode/intel: Check against CPU signature before saving microcode |
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On Tue, Aug 23, 2022 at 11:13:13AM +0000, Ashok Raj wrote: > > > patch1: > > > fms3 <--- header FMS > > > ... > > > ext_sig: > > > fms1 > > > fms2 > > > > > > patch2: new > > > fms2 <--- header FMS > > > > > > Current code takes only fms3 and checks with patch2 fms2. > > > > So, find_matching_signature() does all the signatures matching and > > scanning already. If anything, that function should tell its callers > > whether the patch it is looking at - the fms2 one - should replace the > > current one or not. > > > > I.e., all the logic to say how strong a patch match is, should be > > concentrated there. And then the caller will do the according action. > > I updated the commit log accordingly. Basically find_matching_signature() > is only intended to find a CPU's sig/pf against a microcode image and not > intended to compare between two different images.
Err, what?
find_matching_signature() looks at fmt3 - your example above - and then goes and looks at ext_sig. Also your example above.
So you can teach that function to say with a *separate* return value "replace current patch with this new patch because this new patch is a better fit."
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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