[MODERATED] Re: [PATCH v6 1/9] TAAv6 1

On Thu, Oct 10, 2019 at 12:40:45AM +0100, speck for Andrew Cooper wrote:
> > I don't know what the enabled status of HLE is on the MDS_NO, TAA parts,
> > and whether it is statically disabled with the TSX_CTRL microcode, but
> > if it isn't statically disabled then it needs to be dynamically disabled
> > by bit 0, or a 'CLFLUSH; XBEGIN ...; MOV secret' can still be used to
> > exploit TAA.
> 
> Apologies.  That is the RTM sequence.
> 
> For HLE, I meant 'CLFLUSH; XAQUIRE ...; MOV secret'.

Did we send out a review copy of the white paper for TAA yet?

HLE is kind of buried, but we do say:

   On processors that enumerate IA32_ARCH_CAPABILITIES[TSX_CTRL]
   (bit 7)=1, HLE prefix hints are always ignored.

Which is to say that HLE is unconditionally disabled by the
new microcode for TAA.

-Tony