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Subject: Re: [PATCH v4 06/21] KVM: arm64: Support SDEI_EVENT_CONTEXT hypercall
To:     Gavin Shan <gshan@redhat.com>,
        Shannon Zhao <shannon.zhaosl@gmail.com>,
        kvmarm@lists.cs.columbia.edu
Cc:     maz@kernel.org, pbonzini@redhat.com, will@kernel.org,
        linux-kernel@vger.kernel.org, Jonathan.Cameron@huawei.com
References: <20210815001352.81927-1-gshan@redhat.com>
 <20210815001352.81927-7-gshan@redhat.com>
 <40d818a2-0c91-e06e-6ce8-ac8123b8d1d4@gmail.com>
 <798ecbb0-f369-f3e7-ad50-78acfd902d1d@redhat.com>
 <71b87778-ea60-b01d-9010-789feb1e16fa@redhat.com>
From:   Eric Auger <eauger@redhat.com>
Message-ID: <11bbc0c9-b4b2-473f-1979-a7ea8994d15e@redhat.com>
Date:   Tue, 25 Jan 2022 19:32:42 +0100
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Hi Gavin,

On 1/13/22 8:13 AM, Gavin Shan wrote:
> Hi Shannon,
> 
> On 1/13/22 3:02 PM, Gavin Shan wrote:
>> On 1/11/22 5:43 PM, Shannon Zhao wrote:
>>> On 2021/8/15 8:13, Gavin Shan wrote:
>>>> +static unsigned long kvm_sdei_hypercall_context(struct kvm_vcpu *vcpu)
>>>> +{
>>>> +    struct kvm *kvm = vcpu->kvm;
>>>> +    struct kvm_sdei_kvm *ksdei = kvm->arch.sdei;
>>>> +    struct kvm_sdei_vcpu *vsdei = vcpu->arch.sdei;
>>>> +    struct kvm_sdei_vcpu_regs *regs;
>>>> +    unsigned long index = smccc_get_arg1(vcpu);
>>>> +    unsigned long ret = SDEI_SUCCESS;
>>>> +
>>>> +    /* Sanity check */
>>>> +    if (!(ksdei && vsdei)) {
>>>> +        ret = SDEI_NOT_SUPPORTED;
>>>> +        goto out;
>>>> +    }
>>> Maybe we could move these common sanity check codes to
>>> kvm_sdei_hypercall to save some lines.
>>>
>>
>> Not all hypercalls need this check. For example,
>> COMPLETE/COMPLETE_RESUME/CONTEXT don't
>> have SDEI event number as the argument. If we really want move this
>> check into function
>> kvm_sdei_hypercall(), we would have code like below. Too much
>> duplicated snippets will
>> be seen. I don't think it's better than what we have if I fully
>> understand your comments.
>>
> 
> oops... sorry. Please ignore my previous reply. I thought you talk about
> the check on the SDEI event number wrongly. Yes, you're correct that the
> check should be moved to kvm_sdei_hypercall().

even better than my previous proposal then

Eric
> 
> Thanks,
> Gavin
> 
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