Messages in this thread |  | | Date | Thu, 25 Jan 2018 11:54:20 +0100 (CET) | | From | Thomas Gleixner <> | | Subject | Re: [PATCH v4 6/7] x86/cpufeature: Blacklist SPEC_CTRL on early Spectre v2 microcodes |
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On Thu, 25 Jan 2018, David Woodhouse wrote:
> On Thu, 2018-01-25 at 09:23 +0000, David Woodhouse wrote: > > > > +/* > > + * Early microcode releases for the Spectre v2 mitigation were broken. > > + * Information taken from; > > + * • https://newsroom.intel.com/wp-content/uploads/sites/11/2018/01/microcode-update-guidance.pdf > > Oh look, Intel have released a *third* version of that document > already, and they've bumped the bad Kabylake versions to 0x84, although > they're *still* missing out the KBL 906EA SKU which was updated to 0x80 > in the public 20180108 microcode release. I'll bump them all in my tree > to 0x84. > > Thomas, want another copy in email now, or were we waiting for another > round of these before you merge them anyway?
Looking at this mess makes me even less convinced that a blacklist is a good idea. We have already at least 3 different variants of blacklists.
So I rather see a whitelist approach which says:
if (ucode_version < known_good(family, model)) return;
I know it would require that Intel releases a set of known good ucodes at some point in the future, but that's a reasonable request.
I rather take a few patches which add the cutoff for family/model (and NO, I don't want to add stepping into the mix at all) than having this blacklist mess which keeps changing every other day.
Thanks,
tglx
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