Re: [PATCH v6 1/5] KVM: s390: clean up redundant 'kvm_run' parameters

Christian Borntraeger
2020-06-23T15:33:12Z

On 23.06.20 15:14, Tianjia Zhang wrote:
> In the current kvm version, 'kvm_run' has been included in the 'kvm_vcpu'
> structure. For historical reasons, many kvm-related function parameters
> retain the 'kvm_run' and 'kvm_vcpu' parameters at the same time. This
> patch does a unified cleanup of these remaining redundant parameters.
>
> Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
> arch/s390/kvm/kvm-s390.c | 23 +++++++++++++++--------
> 1 file changed, 15 insertions(+), 8 deletions(-)

Tinajia,

I have trouble seeing value in this particular patch. We add LOCs
without providing any noticable benefit. All other patches in this series at
least reduce the amount of code. So I would defer this to Paolo if he prefers
to have this way across all architectures.
>
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index d47c19718615..f5f96dc33712 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -4175,8 +4175,9 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
> return rc;
> }
>
> -static void sync_regs_fmt2(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
> +static void sync_regs_fmt2(struct kvm_vcpu *vcpu)
> {
> + struct kvm_run *kvm_run = vcpu->run;
> struct runtime_instr_cb *riccb;
> struct gs_cb *gscb;
>
> @@ -4242,8 +4243,10 @@ static void sync_regs_fmt2(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
> /* SIE will load etoken directly from SDNX and therefore kvm_run */
> }
>
> -static void sync_regs(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
> +static void sync_regs(struct kvm_vcpu *vcpu)
> {
> + struct kvm_run *kvm_run = vcpu->run;
> +
> if (kvm_run->kvm_dirty_regs & KVM_SYNC_PREFIX)
> kvm_s390_set_prefix(vcpu, kvm_run->s.regs.prefix);
> if (kvm_run->kvm_dirty_regs & KVM_SYNC_CRS) {
> @@ -4272,7 +4275,7 @@ static void sync_regs(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
>
> /* Sync fmt2 only data */
> if (likely(!kvm_s390_pv_cpu_is_protected(vcpu))) {
> - sync_regs_fmt2(vcpu, kvm_run);
> + sync_regs_fmt2(vcpu);
> } else {
> /*
> * In several places we have to modify our internal view to
> @@ -4291,8 +4294,10 @@ static void sync_regs(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
> kvm_run->kvm_dirty_regs = 0;
> }
>
> -static void store_regs_fmt2(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
> +static void store_regs_fmt2(struct kvm_vcpu *vcpu)
> {
> + struct kvm_run *kvm_run = vcpu->run;
> +
> kvm_run->s.regs.todpr = vcpu->arch.sie_block->todpr;
> kvm_run->s.regs.pp = vcpu->arch.sie_block->pp;
> kvm_run->s.regs.gbea = vcpu->arch.sie_block->gbea;
> @@ -4312,8 +4317,10 @@ static void store_regs_fmt2(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
> /* SIE will save etoken directly into SDNX and therefore kvm_run */
> }
>
> -static void store_regs(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
> +static void store_regs(struct kvm_vcpu *vcpu)
> {
> + struct kvm_run *kvm_run = vcpu->run;
> +
> kvm_run->psw_mask = vcpu->arch.sie_block->gpsw.mask;
> kvm_run->psw_addr = vcpu->arch.sie_block->gpsw.addr;
> kvm_run->s.regs.prefix = kvm_s390_get_prefix(vcpu);
> @@ -4332,7 +4339,7 @@ static void store_regs(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
> current->thread.fpu.fpc = vcpu->arch.host_fpregs.fpc;
> current->thread.fpu.regs = vcpu->arch.host_fpregs.regs;
> if (likely(!kvm_s390_pv_cpu_is_protected(vcpu)))
> - store_regs_fmt2(vcpu, kvm_run);
> + store_regs_fmt2(vcpu);
> }
>
> int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
> @@ -4370,7 +4377,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
> goto out;
> }
>
> - sync_regs(vcpu, kvm_run);
> + sync_regs(vcpu);
> enable_cpu_timer_accounting(vcpu);
>
> might_fault();
> @@ -4392,7 +4399,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
> }
>
> disable_cpu_timer_accounting(vcpu);
> - store_regs(vcpu, kvm_run);
> + store_regs(vcpu);
>
> kvm_sigset_deactivate(vcpu);
>
>