On Tue, Dec 17, 2024 at 04:32:55PM +0100, Thomas De Schampheleire wrote:
Hello,
Below commit was ported to 6.12, but I would like to request porting to the 6.6 longterm branch we are currently using:
commit c809b0d0e52d01c30066367b2952c4c4186b1047 Author: Borislav Petkov (AMD) <bp@alien8.de> Date: 2024-11-19 12:21:33 +0100 x86/microcode/AMD: Flush patch buffer mapping after application [...]The patch itself is small, but the consequence of not patching is large on affected systems (tens of seconds to minutes, of boot delay). See original discussion [1] for details.
The patch in master relies on a variable 'bsp_cpuid_1_eax' introduced in commit 94838d230a6c ("x86/microcode/AMD: Use the family,model,stepping encoded in the patch ID"), but porting that entire commit seems excessive, especially because there are several 'Fixes' commits for that one (e.g. 5343558a868e, d1744a4c975b, 1d81d85d1a19).
I think the simplest prerequisite change is (for Borislav Petkov to confirm):
Please send a set of working, and tested, commits that you wish for us to commit, we can't cherry-pick stuff out of an email like this for obvious reasons :)
And whenever possible, yes, we do want to take the fixes that are in Linus's tree, otherwise maintaining the branch over time gets harder and harder. So just backport them all please.
thanks,
greg k-h