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From: Borislav Petkov <bp@alien8.de>
To: Andi Kleen <andi@firstfloor.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	peterz@infradead.org, x86@kernel.org,
	linux-kernel@vger.kernel.org, eranian@google.com,
	kan.liang@intel.com, isaku.yamahata@intel.com,
	kvm@vger.kernel.org, Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH v1 1/2] x86/cpufeature: Add facility to match microcode revisions
Date: Sat, 6 Oct 2018 20:39:28 +0200	[thread overview]
Message-ID: <20181006183928.GA703@zn.tnic> (raw)
In-Reply-To: <20181006181506.7cycnsg5gtoavtmx@two.firstfloor.org>

On Sat, Oct 06, 2018 at 11:15:07AM -0700, Andi Kleen wrote:
> The matcher can be used to match specific hardware steppings by setting
> the min/max_ucode to 0 or specific microcode revisions 
> (which are associated with steppings)

This better be explained unambiguously.

> We still support the old microcode interface that allows updates
> per CPU, and also it could happen during CPU hotplug.

There are no per CPU microcode updates anymore - it is all or none.

It is actually your microcoders who came up with a bunch of restrictions
like quiescing the cores from doing *anything*, blocking hotplug,
prohibiting updates if a subset of the cores is not online and still not
guaranteeing it'll work all the time because <reasons>.

The actually very simple reason being it is just too late for microcode
update when the machine is up. Where all I wanna do is rip the damn
thing out completely.

-- 
Regards/Gruss,
    Boris.

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

  reply	other threads:[~2018-10-06 18:39 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-06  0:19 [PATCH v1 1/2] x86/cpufeature: Add facility to match microcode revisions Andi Kleen
2018-10-06 14:14 ` Thomas Gleixner
2018-10-06 16:10   ` Thomas Gleixner
2018-10-06 18:15   ` Andi Kleen
2018-10-06 18:39     ` Borislav Petkov [this message]
2018-10-07  5:32     ` Thomas Gleixner
     [not found] ` <20181006001928.28097-2-andi@firstfloor.org>
2018-10-06 14:40   ` [PATCH v1 2/2] perf/x86/kvm: Avoid unnecessary work in guest filtering Thomas Gleixner
2018-10-06 16:13     ` Thomas Gleixner

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