linux-kernel - Re: [PATCH v4 06/21] KVM: arm64: Support SDEI_EVENT_CONTEXT hypercall

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Date:   Tue, 25 Jan 2022 19:32:42 +0100
From:   Eric Auger <eauger@...hat.com>
To:     Gavin Shan <gshan@...hat.com>,
        Shannon Zhao <shannon.zhaosl@...il.com>,
        kvmarm@...ts.cs.columbia.edu
Cc:     maz@...nel.org, pbonzini@...hat.com, will@...nel.org,
        linux-kernel@...r.kernel.org, Jonathan.Cameron@...wei.com
Subject: Re: [PATCH v4 06/21] KVM: arm64: Support SDEI_EVENT_CONTEXT hypercall

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
> 
> _______________________________________________
> kvmarm mailing list
> kvmarm@...ts.cs.columbia.edu
> https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

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