Re: [Qemu-devel] [PATCH 2/2] target-i386: Haswell-noTSX and Broadwell-noTSX

[Daniel P. Berrange]

On Thu, Mar 19, 2015 at 03:02:27PM -0300, Eduardo Habkost wrote:
> On Mon, Mar 16, 2015 at 10:24:51AM +0000, Daniel P. Berrange wrote:
> > On Fri, Mar 13, 2015 at 04:09:57PM -0300, Eduardo Habkost wrote:
> > > With the Intel microcode update that removed HLE and RTM, there will be
> > > different kinds of Haswell and Broadwell CPUs out there: some that still
> > > have the HLE and RTM features, and some that don't have the HLE and RTM
> > > features. On both cases people may be willing to use the pc-*-2.3
> > > machine-types.
> > > 
> > > So, to cover both cases, introduce Haswell-noTSX and Broadwell-noTSX CPU
> > > models, for hosts that have Haswell and Broadwell CPUs without TSX 
> > > support.
> > > 
> > > Signed-off-by: Eduardo Habkost <address@hidden>
> > 
> > The addition of Haswell-noTSX looks good to me.
> > 
> > I'm unclear on whether we truely need Broadwell-noTSX though. Did
> > Intel actually ship any Broadwell production silicon in which the
> > microcode disables this feature, or was it only a problem on
> > pre-production samples of Broadwell ? If the latter, I'd say we
> > don't need to have a Broadwell-noTSX model added. Perhaps Jun/Don
> > can confirm from Intel's side.
> 
> I've talked to Don and Jun, and they confirmed that a Broadwell-noTSX
> CPU model will be needed, too.
> 
> I see some Broadwell CPUs without TSX-NI on ark.intel.com, too, so the
> TSX errata wouldn't be the only reason for needing the -noTSX model.

Ok, your patch looks good.

  Reviewed-by: Daniel P. Berrange <address@hidden>

Regards,
Daniel
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