Re: [PATCH] x86/speculation: Add document to describe Spectre and its mitigations

[Ben Greear]

On 12/21/2018 05:17 PM, Tim Chen wrote:
> On 12/21/18 1:59 PM, Ben Greear wrote:
> > On 12/21/18 9:44 AM, Tim Chen wrote:
> > > Thomas,
> > >
> > > Andi and I have made an update to our draft of the Spectre admin guide.
> > > We may be out on Christmas vacation for a while.  But we want to
> > > send it out for everyone to take a look.
> >
> > Can you add a section on how to compile out all mitigations that have anything
> > beyond negligible performance impact for those running systems where performance
> > is more important than security?
>
> If you don't worry about security and performance is paramount, then
> boot with "nospectre_v2".  That's explained in the document.

There seem to be lots of different variants of this type of problem.  It was not clear
to me that just doing nospectre_v2 would be sufficient to get back full performance.

And anyway, I would like to compile the kernel to not need that command-line option,
so I am still interesting in what compile options need to be set to what values...

Thanks,
Ben

--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc  http://www.candelatech.com