Re: [PATCH v2 3/3] x86/ucode: load microcode earlier on boot CPU

[Julien Grall <julien@xxxxxxx>]

Hi Sergey,

On 19/12/2022 14:45, Sergey Dyasli wrote:
> Call early_microcode_init() straight after multiboot modules become
> accessible. Modify it to load the ucode directly from the blob bypassing
> populating microcode_cache because xmalloc is still not available at
> that point during Xen boot.
>
> Introduce early_microcode_init_cache() for populating microcode_cache.
> It needs to rescan the modules in order to find the new virtual address
> of the ucode blob because it changes during the boot process, e.g.
> from 0x00000000010802fc to 0xffff83204dac52fc.
>
> While at it, drop alternative_vcall() from early_microcode_init() since
> it's not useful in an __init fuction.
Can you explain in the commit message why you need to load the microcode 
early? E.g. is it a nice feature to have or a real issue?
If the latter, then I think we will need to consider the patches for 
backport.
Cheers,

--
Julien Grall