[MODERATED] Re: [PATCH 3/9] TAA 3

On 24/10/2019 21:36, speck for Borislav Petkov wrote:
> On Thu, Oct 24, 2019 at 03:14:03PM -0500, speck for Josh Poimboeuf wrote:
>> Actually, according to the patches, with TSX_CTRL CPUs, HLE is
>> unconditionally disabled, but still enumerated as present in CPUID
>> (why???)
> I found it: in an older email thread Andrew talks about migration
> compatibility and HLE. Dunno if we care but maybe someone else has a
> better idea.

The first TSX problem in Haswell/Broadwell lead to chaos when a
microcode update took feature bits out.

When the second problem came around, I understand from IRL conversations
that several vendors firmly expressed their opinion about whether
feature bits should disappear in microcode.

As HLE is a hint bit at best, it was left visible despite being disabled
behind the scenes.

~Andrew