Re: [Xen-devel] [PATCH 1/3] x86/spec-ctrl: add AMD SSBD LS_CFG in init print

[Brian Woods <brian.woods@xxxxxxx>]

On Tue, Jul 31, 2018 at 04:47:48AM -0600, Jan Beulich wrote:
> Pointless initializer.

Noted

> Why log the same string twice? Simply OR together both conditions.
> Also please don't omit the blank before the ? operator. Both remarks
> apply as well further down.

Because they're completely different implementation at this point.  I
thought about naming it something else but couldn't think of something.
It also reads easier with having them split up where there isn't a ton
of logic in a single ternary operator.  There can be easily changed.

> I've peeked ahead into the following patches, and I can't see
> why this needs to be a synthetic feature flag. We use such flags
> for the purpose of alternative instruction patching, but you don't
> do anything like that.
> 
> Jan

I was talking Andy earily about a SSBD (via VIRT_SPEC_CTRL)
implementation and he mentioned something about ALTERNATIVE C funcs
which would allow to allow HVM guests to be able control SSBD.  In that
case having a synthetic feature flag is useful for helping to
differiate between SSBD via the LS_CFG MSR vs SPEC_CTRL in the future.


-- 
Brian Woods

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel