Re: [Xen-devel] [PATCH v3 for 4.13] x86/microcode: refuse to load the same revision ucode

[Jan Beulich <jbeulich@xxxxxxxx>]

On 26.11.2019 16:41, Sergey Dyasli wrote:
> Currently if a user tries to live-load the same or older ucode revision
> than CPU already has, he will get a single message in Xen log like:
> 
>     (XEN) 128 cores are to update their microcode
> 
> No actual ucode loading will happen and this situation can be quite
> confusing. Fix this by starting ucode update only when the provided
> ucode revision is higher than the currently cached one (if any).
> This is based on the property that if microcode_cache exists, all CPUs
> in the system should have at least that ucode revision.
> 
> Additionally, print a user friendly message if no matching or newer
> ucode can be found in the provided blob. This also requires ignoring
> -ENODATA in AMD-side code, otherwise the message given to the user is:
> 
>     (XEN) Parsing microcode blob error -61
> 
> Which actually means that a ucode blob was parsed fine, but no matching
> ucode was found.
> 
> Signed-off-by: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>

Acked-by: Jan Beulich <jbeulich@xxxxxxxx>

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