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Date:   Thu, 5 Sep 2019 13:20:19 -0700
From:   "Raj, Ashok" <ashok.raj@intel.com>
To:     Borislav 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: <20190905202019.GA3649@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>
 <20190905002132.GA26568@otc-nc-03>
 <20190905072029.GB19246@zn.tnic>
 <20190905194044.GA3663@otc-nc-03>
 <20190905194950.GH19246@zn.tnic>
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On Thu, Sep 05, 2019 at 09:49:50PM +0200, Borislav Petkov wrote:
> On Thu, Sep 05, 2019 at 12:40:44PM -0700, Raj, Ashok wrote:
> > The original description said to load a new microcode file, the content
> > could have changed, but revision in the header hasn't increased.
> 
> How does the hardware even accept a revision which is the same as the
> one already loaded?

Hardware will allow a reload as long as the loaded ucode svn <= the version being updated.