On Mon, Jun 30, 2025 at 11:34:34AM +0000, Huang, Kai wrote:
> Yeah I agree the text can be improved. I tried to run AI to simplify but so
> far I am not quite happy about the result yet. I'll try more.
Ask it to simplify it. I get it that you want to be exhaustive in your commit
message but there really is such thing as too much text.
Think of it this way: is the text I'm writing optimal when anyone needs to
read it in the future to know why a change has been done. If not, try to make
it so.
> Yeah I agree a single u32 + flags is better. However this is the problem in
> the existing code (this patch only does renaming).
>
> I think I can come up with a patch to clean this up and put it as the first
> patch of this series, or I can do a patch to clean this up after this series
> (either together with this series, or separately at a later time). Which
> way do you prefer?
Clean ups go first, so yeah, please do a cleanup pre-patch.
> /*
> * The cache may be in an incoherent state (e.g., due to memory
> * encryption) and needs flushing during kexec.
> */
Better than nothing. I'd try to explain with 1-2 sentences what can happen due
to memory encryption and why cache invalidation is required. So that the
comment is standalone and is not sending you on a wild goose chasing ride.
> IIUC the X86_FEATURE_SME could be cleared via 'clearcpuid' kernel cmdline.
>
> Please also see my reply to Tom.
I know but we have never said that clearcpuid= should be used in production.
If you break the kernel using it, you get to keep the pieces. clearcpuid=
taints the kernel and screams bloody murder. So I'm not too worried about
that.
What is more relevant is this:
"I did verify that booting with mem_encrypt=off will start with
X86_FEATURE_SME set, the BSP will clear it and then all APs will not see
it set after that."
which should be put there in the comment.
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
