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    SubjectRe: [PATCH 2/2] x86, microcode: Make reload interface per system
    On 06/20/2012 04:46 PM, Borislav Petkov wrote:
    >>
    >> Except you still need to re-poke it when you have a new microcode
    >> blob... so what was gained by all this churn?
    >
    > We need to do that anyway if new (F,M,S) ucode piece comes along.
    >
    > The gain is twofold:
    >
    > * we don't need the userspace tool to split the blob - we have one
    > single file we load and the driver picks out what it needs.
    >
    > * as a result, we drop the CONFIG_MICROCODE_OLD_INTERFACE, i.e.
    > /dev/cpu/microcode which takes the single blob anyway which the driver
    > picks apart later.
    >
    > In the end, we have one unified ucode loading procedure:
    >
    > 1. put the blob in /lib/firmware/...
    > 2. echo 1 > /sys/devices/system/cpu/microcode/reload
    >
    > That's it - it can't be simpler than that.
    >

    I really don't get why the whole thing is any simpler than the old
    /dev/cpu/microcode interface in the first place, where instead of:

    > 1. put the blob in /lib/firmware/...
    > 2. echo 1 > /sys/devices/system/cpu/microcode/reload

    ... you do ...

    1. dd if=<microcode blob> of=/dev/cpu/microcode bs=<large>

    ... as well as set up the early initramfs part, of course.

    -hpa



    --
    H. Peter Anvin, Intel Open Source Technology Center
    I work for Intel. I don't speak on their behalf.



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