Date: Mon, 15 Jan 2018 11:10:16 +0100
From: Borislav Petkov <bp@alien8.de>
To: Jia Zhang <zhang.jia@linux.alibaba.com>
Cc: tony.luck@intel.com, mingo@redhat.com, hpa@zytor.com,
        tglx@linutronix.de, x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] x86/microcode/intel: Extend BDW late-loading with
 platform id and LLC check
Message-ID: <20180115101016.k4ksjlclufogcfrt@pd.tnic>
References: <1515995003-113069-1-git-send-email-zhang.jia@linux.alibaba.com>
 <1515995003-113069-3-git-send-email-zhang.jia@linux.alibaba.com>
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On Mon, Jan 15, 2018 at 01:43:23PM +0800, Jia Zhang wrote:
> The commit b94b73733171
> ("x86/microcode/intel: Extend BDW late-loading with a revision check")
> reduces the impact of erratum BDF90 for Broadwell process model. Now,
> the impact can be reduced further through adding the checks for
> platform id and the size of LLC per core.
> 
> This fix is useful to reduce the impact for microcode update launched
> by BIOS with a must machine reset.
> 
> For more details, see erratum BDF90 in document #334165 (Intel Xeon
> Processor E7-8800/4800 v4 Product Family Specification Update) from
> September 2017.

You must be looking at something NDA or so but this:

https://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/xeon-e7-v4-spec-update.pdf

doesn't have none of that

> +         llc_size_per_core(c) > 2621440 &&
> +         c->platform_id == 0xef &&

fun.

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.