>>> On 06.02.18 at 14:48, <andrew.coop...@citrix.com> wrote:
> The original version of this logic was:
>
> /*
> * On Intel hardware, we'd like to use retpoline in preference to
> * IBRS, but only if it is safe on this hardware.
> */
> else if ( boot_cpu_has(X86_FEATURE_IBRSB) )
> {
> if ( retpoline_safe() )
> thunk = THUNK_RETPOLINE;
> else
> ibrs = true;
> }
>
> but it was changed by a request during review. Sadly, the result is buggy as
> it breaks the later fallback logic by allowing IBRS to appear as available
> when in fact it isn't.
>
> This in practice means that on repoline-unsafe hardware without IBRS, we
> select THUNK_JUMP despite intending to select THUNK_RETPOLINE.
>
> Reported-by: Zhenzhong Duan <zhenzhong.d...@oracle.com>
> Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
Reviewed-by: Jan Beulich <jbeul...@suse.com>
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