Re: [PATCH 3/8] kvm: vmx: pass MSR_IA32_SPEC_CTRL and MSR_IA32_PRED_CMD down to the guest

[Paolo Bonzini]

On 10/01/2018 15:06, Arjan van de Ven wrote:
> On 1/10/2018 5:20 AM, Paolo Bonzini wrote:
>> * a simple specification that does "IBRS=1 blocks indirect branch
>> prediction altogether" would actually satisfy the specification just as
>> well, and it would be nice to know if that's what the processor actually
>> does.
> 
> it doesn't exactly, not for all.
> 
> so you really do need to write ibrs again.

Okay, so "always set IBRS=1" does *not* protect against variant 2.  Thanks,

Paolo