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    SubjectRe: Fix built-in early-load Intel microcode alignment
    On Wed, Jan 15, 2020 at 08:46:04PM +0200, Jari Ruusu wrote:
    > On 1/15/20, Luis Chamberlain <mcgrof@kernel.org> wrote:
    > > On Mon, Jan 13, 2020 at 09:58:25PM +0200, Jari Ruusu wrote:
    > >> Before that 16-byte alignment patch was applied, my only one
    > >> microcode built-in BLOB was "accidentally" 16-byte aligned.
    > >
    > > How did it accidentially get 16-byte aligned?
    >
    > Old code aligned it to 8-bytes.
    > There is 50/50-chance of it also being 16-byte aligned.

    But *how? Why is there a 50/50 chance of it being aligned to
    16 bytes if 8 bytes are currently specified?

    > So it ended up being both 8-byte and 16-byte aligned.

    What do you mean both? How can it be aligned to both?

    > > Also, how do you *know* something is broken right now?
    >
    > I haven't spotted brokenness in Linux microcode loader other
    > than that small alignment issue.
    >
    > However, I can confirm that there are 2 microcode updates newer
    > than what my laptop computer's latest BIOS includes. Both newer
    > ones (20191115 and 20191112) are unstable on my laptop computer
    > i5-7200U (fam 6 model 142 step 9 pf 0x80). Hard lockups with both
    > of them. Back to BIOS microcode for now.

    I was more interested in how you are *certain*, other than manualcode
    inspection, and that a spec indicates we should use 16 bytes for Intel
    microcode -- that the 8 byte alignment *does* not allow users to
    currently update their Intel CPU microcode for built-in firmware.

    From what I gather so far we have no case yet reported where we know for
    sure it fails right now with the 8 byte alignment on 64-bit.

    This information would just be useful for the commit log.

    Luis

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