lkml.org 
[lkml]   [2022]   [Aug]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 3/5] x86/microcode/intel: Allow a late-load only if a min rev is specified
On Sat, Aug 13, 2022 at 10:38:23PM +0000, Ashok Raj wrote:

> The proposal here is an even simpler option. The criteria for a microcode to
> be a viable late-load candidate is that no CPUID or OS visible MSR features
> are removed with respect to an earlier version of the microcode.
>
> Pseudocode for late-load is as follows:
>
> if header.min_required_id == 0
> This is old format microcode, block late-load
> else if current_ucode_version < header.min_required_id
> Current version is too old, block late-load of this microcode.
> else
> OK to proceed with late-load.

What about ucode that adds CPUID bits? Since the kernel will not re-init
it will not pick up on those. But userspace might.

Should we at all time enable CPUID intercept to ensure user visible
CPUID doesn't change?

\
 
 \ /
  Last update: 2022-08-15 09:44    [W:0.191 / U:0.180 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site