Reply-To: Gavin Shan <gshan@redhat.com>
Subject: Re: [PATCH v4 02/21] KVM: arm64: Add SDEI virtualization
 infrastructure
To:     Shannon Zhao <shannon.zhaosl@gmail.com>,
        kvmarm@lists.cs.columbia.edu
Cc:     maz@kernel.org, linux-kernel@vger.kernel.org,
        Jonathan.Cameron@huawei.com, pbonzini@redhat.com, will@kernel.org
References: <20210815001352.81927-1-gshan@redhat.com>
 <20210815001352.81927-3-gshan@redhat.com>
 <89165079-d2a6-fad8-3a9c-dcb46a8acdc7@gmail.com>
From:   Gavin Shan <gshan@redhat.com>
Message-ID: <41ccffa1-4094-7e71-246f-ac11023f741a@redhat.com>
Date:   Thu, 13 Jan 2022 15:09:32 +0800
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Hi Shannon,

On 1/11/22 5:40 PM, Shannon Zhao wrote:
> On 2021/8/15 8:13, Gavin Shan wrote:
>> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
>> index e9a2b8f27792..2f021aa41632 100644
>> --- a/arch/arm64/kvm/arm.c
>> +++ b/arch/arm64/kvm/arm.c
>> @@ -150,6 +150,8 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
>>       kvm_vgic_early_init(kvm);
>> +    kvm_sdei_init_vm(kvm);
>> +
>>       /* The maximum number of VCPUs is limited by the host's GIC model */
>>       kvm->arch.max_vcpus = kvm_arm_default_max_vcpus();
> Hi, Is it possible to let user space to choose whether enabling SEDI or not rather than enable it by default?
> 

It's possible, but what's the benefit to do so. I think about it for
a while and I don't think it's not necessary, at least for now. First
of all, the SDEI event is injected from individual modules in userspace
(QEMU) or host kernel (Async PF). If we really want the function to be
disabled, the individual modules can accept parameter, used to indicate
the SDEI event injection is allowed or not. In this case, SDEI is enabled
by default, but the individual modules can choose not to use it :)

Thanks,
Gavin