Re: [PATCH v3 1/4] x86/speculation: Use IBRS if available before calling into firmware

[Thomas Gleixner]

On Mon, 19 Feb 2018, David Woodhouse wrote:

> Retpoline means the kernel is safe because it has no indirect branches.
> But firmware isn't, so use IBRS for firmware calls if it's available.
> 
> Block preemption while IBRS is set, although in practice the call sites
> already had to be doing that.
> 
> Ignore hpwdt.c for now. It's taking spinlocks and calling into firmware
> code, from an NMI handler. I don't want to touch that with a bargepole.
> 
> Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>

Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>