linux-kernel - Re: x86, microcode: BUG: microcode update that changes x86

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Message-ID: <20140925121007.GA25334@nazgul.tnic>
Date:	Thu, 25 Sep 2014 14:10:07 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	Henrique de Moraes Holschuh <hmh@....eng.br>
Cc:	Chuck Ebbert <cebbert.lkml@...il.com>,
	Andy Lutomirski <luto@...capital.net>,
	"H. Peter Anvin" <hpa@...or.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: x86, microcode: BUG: microcode update that changes x86_capability

On Thu, Sep 25, 2014 at 08:36:45AM -0300, Henrique de Moraes Holschuh wrote:
> This isn't an useless fix, it will allow systems without early initramfs
> support to operate correctly after a microcode update.

So what do we do if we update the microcode late and some userspace task
is using HLE and all of a sudden it segfaults and gets killed due to
#UD. I'll forward all those complaint emails to you then, no?

:-)

What's saying is, a reboot in this case is maybe the lesser of two evils.

-- 
Regards/Gruss,
    Boris.
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