linux-kernel - Re: [PATCH v4 1/7] KVM: s390: clean up redundant 'kvm

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Date:   Wed, 29 Apr 2020 14:03:41 +0200
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     Tianjia Zhang <tianjia.zhang@...ux.alibaba.com>
Cc:     kvm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        kvmarm@...ts.cs.columbia.edu, linux-mips@...r.kernel.org,
        kvm-ppc@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-s390@...r.kernel.org, linux-kernel@...r.kernel.org,
        tianjia.zhang@...ux.alibaba.com, pbonzini@...hat.com,
        tsbogend@...ha.franken.de, paulus@...abs.org, mpe@...erman.id.au,
        benh@...nel.crashing.org, borntraeger@...ibm.com,
        frankja@...ux.ibm.com, david@...hat.com, cohuck@...hat.com,
        heiko.carstens@...ibm.com, gor@...ux.ibm.com,
        sean.j.christopherson@...el.com, wanpengli@...cent.com,
        jmattson@...gle.com, joro@...tes.org, tglx@...utronix.de,
        mingo@...hat.com, bp@...en8.de, x86@...nel.org, hpa@...or.com,
        maz@...nel.org, james.morse@....com, julien.thierry.kdev@...il.com,
        suzuki.poulose@....com, christoffer.dall@....com,
        peterx@...hat.com, thuth@...hat.com, chenhuacai@...il.com
Subject: Re: [PATCH v4 1/7] KVM: s390: clean up redundant 'kvm_run' parameters

Tianjia Zhang <tianjia.zhang@...ux.alibaba.com> writes:

> 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@...ux.alibaba.com>
> ---
>  arch/s390/kvm/kvm-s390.c | 23 +++++++++++++++--------
>  1 file changed, 15 insertions(+), 8 deletions(-)
>
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index e335a7e5ead7..c0d94eaa00d7 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -4176,8 +4176,9 @@ 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;
>  
> @@ -4243,8 +4244,10 @@ 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) {
> @@ -4273,7 +4276,7 @@ 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
> @@ -4292,8 +4295,10 @@ 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;
> @@ -4313,8 +4318,10 @@ 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);
> @@ -4333,7 +4340,7 @@ 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)
> @@ -4371,7 +4378,7 @@ 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();
> @@ -4393,7 +4400,7 @@ 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);

Haven't tried to compile this but the change itself looks obviously
correct, so

Reviewed-by: Vitaly Kuznetsov <vkuznets@...hat.com>

-- 
Vitaly