Re: [PATCH v3 4/6] x86/bugs: Don't fill RSB on VMEXIT with eIBRS+retpoline

[Nikolay Borisov]

On 2.04.25 г. 21:19 ч., Josh Poimboeuf wrote:
> eIBRS protects against guest->host RSB underflow/poisoning attacks.
> Adding retpoline to the mix doesn't change that.  Retpoline has a
> balanced CALL/RET anyway.
>
> So the current full RSB filling on VMEXIT with eIBRS+retpoline is
> overkill.  Disable it or do the VMEXIT_LITE mitigation if needed.
>
> Suggested-by: Pawan Gupta <pawan.kumar.gupta@xxxxxxxxxxxxxxx>
> Reviewed-by: Pawan Gupta <pawan.kumar.gupta@xxxxxxxxxxxxxxx>
> Reviewed-by: Amit Shah <amit.shah@xxxxxxx>
> Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>

Reviewed-by: Nikolay Borisov <nik.borisov@xxxxxxxx>