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Date:   Wed, 4 Sep 2019 17:21:32 -0700
From:   "Raj, Ashok" <ashok.raj@intel.com>
To:     Boris Petkov <bp@alien8.de>
Cc:     Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Mihai Carabas <mihai.carabas@oracle.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
        Jon Grimm <Jon.Grimm@amd.com>, kanth.ghatraju@oracle.com,
        konrad.wilk@oracle.com, patrick.colp@oracle.com,
        Thomas Gleixner <tglx@linutronix.de>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        x86-ml <x86@kernel.org>, linux-kernel@vger.kernel.org,
        Ashok Raj <ashok.raj@intel.com>
Subject: Re: [PATCH] x86/microcode: Add an option to reload microcode even if
 revision is unchanged
Message-ID: <20190905002132.GA26568@otc-nc-03>
References: <1567056803-6640-1-git-send-email-ashok.raj@intel.com>
 <20190829060942.GA1312@zn.tnic>
 <20190829130213.GA23510@araj-mobl1.jf.intel.com>
 <20190903164630.GF11641@zn.tnic>
 <41cee473-321c-2758-032a-ccf0f01359dc@oracle.com>
 <D8A3D2BD-1FD4-4183-8663-3EF02A6099F3@alien8.de>
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On Thu, Sep 05, 2019 at 12:12:29AM +0200, Boris Petkov wrote:
> On September 5, 2019 12:06:54 AM GMT+02:00, Boris Ostrovsky <boris.ostrovsky@oracle.com> wrote:
> >Why do we need to taint kernel here? We are not making any changes.
> 
> Because this is not a normal operation we want users to do. This is only for testing microcode quicker.
> 
> >This won't allow people to load from new microcode blob which I thought
> >was one of the objectives behind this new feature.
> 
> You load a new blob the usual way: echo 1 > ...
> 
> This is the "unusual" way where you reload an already loaded revision only.

But echo 2 > reload would allow reading a microcode file from 
/lib/firmware/intel-ucode/ even if the revision hasn't changed right?

#echo 1 > reload wouldn't load if the revision on disk is same as what's loaded,
and we want to permit that with the echo 2 option.