Messages in this thread | | | Subject | Re: [PATCH 2/2] x86/microcode/intel: Extend BDW late-loading with platform id and LLC check | From | Jia Zhang <> | Date | Mon, 15 Jan 2018 21:07:15 +0800 |
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在 2018/1/15 下午7:48, Henrique de Moraes Holschuh 写道: > On Mon, 15 Jan 2018, Jia Zhang wrote: >> For more details, see erratum BDF90 in document #334165 (Intel Xeon >> Processor E7-8800/4800 v4 Product Family Specification Update) from >> September 2017. > > For the record, this erratum may well affect some E5v4 as well. > Anything with a LLC/core ratio >= 2.5 is potentially affected as far as > I could tell when I took a serious look at it months ago (based only on > crash reports and public information). > > It would be safer to just blacklist by sig == 0x406f1, revision < > 0x0b00021, and LLC/core ratio >= 2.5, ignoring platform IDs. > >> /* >> * Late loading on model 79 with microcode revision less than 0x0b000021 >> - * may result in a system hang. This behavior is documented in item >> - * BDF90, #334165 (Intel Xeon Processor E7-8800/4800 v4 Product Family). >> + * and LLC size per core bigger than 2.5MB may result in a system hang. >> + * This behavior is documented in item BDF90, #334165 (Intel Xeon >> + * Processor E7-8800/4800 v4 Product Family). >> */ >> if (c->x86 == 6 && >> c->x86_model == INTEL_FAM6_BROADWELL_X && >> c->x86_mask == 0x01 && >> + llc_size_per_core(c) > 2621440 && >> + c->platform_id == 0xef && >> c->microcode < 0x0b000021) { >> pr_err_once("Erratum BDF90: late loading with revision < 0x0b000021 (0x%x) disabled.\n", c->microcode); >> pr_err_once("Please consider either early loading through initrd/built-in or a potential BIOS update.\n"); > > The c->platform_id test looks wrong. The processor will only have a > single bit set, it is the microcode update that has more than a single > bit set. > > And do you really want 0xef? That is everyhing the public available > microcode updates can be applied to in the first place, so even a > corrected test would be useless (it would always match) unless you > actually expect to find never-seen-in-the-wild platform mask 0x10?
Yes you are right. That platform id is used in microcode update for matching compare. I will drop platform id in v2.
Jia
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