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Subject: Re: [PATCH v2 1/7] KVM: s390: clean up redundant 'kvm_run' parameters
To:     Christian Borntraeger <borntraeger@de.ibm.com>,
        Cornelia Huck <cohuck@redhat.com>
Cc:     pbonzini@redhat.com, tsbogend@alpha.franken.de, paulus@ozlabs.org,
        mpe@ellerman.id.au, benh@kernel.crashing.org,
        frankja@linux.ibm.com, david@redhat.com, heiko.carstens@de.ibm.com,
        gor@linux.ibm.com, sean.j.christopherson@intel.com,
        vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com,
        joro@8bytes.org, tglx@linutronix.de, mingo@redhat.com,
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        james.morse@arm.com, julien.thierry.kdev@gmail.com,
        suzuki.poulose@arm.com, christoffer.dall@arm.com,
        peterx@redhat.com, thuth@redhat.com, kvm@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu,
        linux-mips@vger.kernel.org, kvm-ppc@vger.kernel.org,
        linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20200422125810.34847-1-tianjia.zhang@linux.alibaba.com>
 <20200422125810.34847-2-tianjia.zhang@linux.alibaba.com>
 <20200422154543.2efba3dd.cohuck@redhat.com>
 <dc5e0fa3-558b-d606-bda9-ed281cf9e9ae@de.ibm.com>
From:   Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Message-ID: <ed11e51e-7861-a93d-ac9f-ae81f94630b0@linux.alibaba.com>
Date:   Thu, 23 Apr 2020 11:14:49 +0800
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On 2020/4/22 23:58, Christian Borntraeger wrote:
> 
> 
> On 22.04.20 15:45, Cornelia Huck wrote:
>> On Wed, 22 Apr 2020 20:58:04 +0800
>> Tianjia Zhang <tianjia.zhang@linux.alibaba.com> wrote:
>>
>>> In the current kvm version, 'kvm_run' has been included in the 'kvm_vcpu'
>>> structure. Earlier than historical reasons, many kvm-related function
>>
>> s/Earlier than/For/ ?
>>
>>> 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>
>>> ---
>>>   arch/s390/kvm/kvm-s390.c | 37 ++++++++++++++++++++++---------------
>>>   1 file changed, 22 insertions(+), 15 deletions(-)
>>>
>>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
>>> index e335a7e5ead7..d7bb2e7a07ff 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;
>>>   
>>> @@ -4235,7 +4236,7 @@ static void sync_regs_fmt2(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
>>>   		}
>>>   		if (vcpu->arch.gs_enabled) {
>>>   			current->thread.gs_cb = (struct gs_cb *)
>>> -						&vcpu->run->s.regs.gscb;
>>> +						&kvm_run->s.regs.gscb;
>>
>> Not sure if these changes (vcpu->run-> => kvm_run->) are really worth
>> it. (It seems they amount to at least as much as the changes advertised
>> in the patch description.)
>>
>> Other opinions?
> 
> Agreed. It feels kind of random. Maybe just do the first line (move kvm_run from the
> function parameter list into the variable declaration)? Not sure if this is better.
> 

Why not, `kvm_run` is equivalent to `vcpu->run`, which is also part of 
the cleanup, or do you mean to put this change in another patch?

Thanks,
Tianjia