Re: [RFC 05/10] x86/speculation: Add basic IBRS support infrastructure

[Greg Kroah-Hartman]

On Mon, Jan 22, 2018 at 01:06:18PM +0100, Borislav Petkov wrote:
> On Mon, Jan 22, 2018 at 10:51:53AM +0100, Peter Zijlstra wrote:
> > That wouldn't be enough; AFAIU there's people with this stuff already
> > flashed in their BIOS. So the kernel needs to deal with it one way or
> > another.
> 
> Not a lot we can do there except maybe disable IBRS on those and users
> can go and complain to their BIOS vendor to give them a downgrade or
> they can downgrade themselves.
> 
> If we had free BIOS, this would've been a whole different story...

We kind of do, you can submit patches to UEFI, but I doubt that the
processor-specific portions are actually present in the Tianocore code
to be able to be patched.

What about LinuxBoot <https://linuxboot.org>, does it too take over too
late in the boot process to control this?

thanks,

greg k-h