Re: [RFC,05/10] x86/speculation: Add basic IBRS support infrastructure
From: Arjan van de Ven
Date: Mon Jan 29 2018 - 15:44:24 EST
On 1/29/2018 12:42 PM, Eduardo Habkost wrote:
The question is how the hypervisor could tell that to the guest.
If Intel doesn't give us a CPUID bit that can be used to tell
that retpolines are enough, maybe we should use a hypervisor
CPUID bit for that?
the objective is to have retpoline be safe everywhere and never use IBRS
(Linus was also pretty clear about that) so I'm confused by your question