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.
next prev parent 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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