Re: [PATCH] LoongArch: KVM: Remove unnecessary CSR register saving during enter guest

[zhaotianrui]

Reviewed-by: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>

在 2024/1/31 上午11:48, maobibo 写道:
> slightly ping :)
>
> On 2024/1/12 上午11:50, Bibo Mao wrote:
> > Some CSR registers like CRMD/PRMD are saved during enter VM mode. However
> > they are not restored for actual use, saving for these CSR registers
> > can be removed.
> >
> > Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx>
> > ---
> >   arch/loongarch/kvm/switch.S | 6 ------
> >   1 file changed, 6 deletions(-)
> >
> > diff --git a/arch/loongarch/kvm/switch.S b/arch/loongarch/kvm/switch.S
> > index 0ed9040307b7..905b90de50e8 100644
> > --- a/arch/loongarch/kvm/switch.S
> > +++ b/arch/loongarch/kvm/switch.S
> > @@ -213,12 +213,6 @@ SYM_FUNC_START(kvm_enter_guest)
> >       /* Save host GPRs */
> >       kvm_save_host_gpr a2
> > -    /* Save host CRMD, PRMD to stack */
> > -    csrrd    a3, LOONGARCH_CSR_CRMD
> > -    st.d    a3, a2, PT_CRMD
> > -    csrrd    a3, LOONGARCH_CSR_PRMD
> > -    st.d    a3, a2, PT_PRMD
> > -
> >       addi.d    a2, a1, KVM_VCPU_ARCH
> >       st.d    sp, a2, KVM_ARCH_HSP
> >       st.d    tp, a2, KVM_ARCH_HTP
> >
> > base-commit: de927f6c0b07d9e698416c5b287c521b07694cac