Re: [PATCH v2 1/3] x86/pv: Options to disable and/or compile out 32bit PV support

[Jan Beulich <jbeulich@xxxxxxxx>]

On 29.04.2020 15:06, Andrew Cooper wrote:
> This is the start of some performance and security-hardening improvements,
> based on the fact that 32bit PV guests are few and far between these days.
> 
> Ring1 is full of architectural corner cases, such as counting as supervisor
> from a paging point of view.  This accounts for a substantial performance hit
> on processors from the last 8 years (adjusting SMEP/SMAP on every privilege
> transition), and the gap is only going to get bigger with new hardware
> features.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Reviewed-by: Wei Liu <wl@xxxxxxx>
> Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>

Acked-by: Jan Beulich <jbeulich@xxxxxxxx>