[PATCH v1 0/7] KVM: arm64: Fix handling of host fpsimd/sve state in protected mode

[Fuad Tabba]

On Mon, May 20, 2024 at 6:53 PM Mark Brown <broonie at kernel.org> wrote:
>
> On Mon, May 20, 2024 at 05:37:36PM +0000, Oliver Upton wrote:
>
> > Wouldn't it be equally valid to just zero the state that will not be
> > preserved regardless of whether or not the guest used fpsimd/sve?
>
> FWIW I've had this benchmarked for some implementations as causing a low
> single digits percentage overhead on syscalls (as you'd expect there's
> additional overhead when VLs over 128 are supported).

Interesting. Is this an argument in favor of zeroing (i.e., the
overhead is low and acceptable), or against (it is still an overhead)?

Thanks,
/fuad