linux-kernel - Re: [PATCH v19 116/130] KVM: TDX: Silently discard SMI request

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Date: Wed, 12 Jun 2024 21:06:40 +0800
From: Binbin Wu <binbin.wu@...ux.intel.com>
To: Paolo Bonzini <pbonzini@...hat.com>
Cc: Sean Christopherson <seanjc@...gle.com>, isaku.yamahata@...el.com,
 kvm@...r.kernel.org, linux-kernel@...r.kernel.org, isaku.yamahata@...il.com,
 erdemaktas@...gle.com, Sagi Shahar <sagis@...gle.com>,
 Kai Huang <kai.huang@...el.com>, chen.bo@...el.com, hang.yuan@...el.com,
 tina.zhang@...el.com
Subject: Re: [PATCH v19 116/130] KVM: TDX: Silently discard SMI request



On 6/11/2024 10:11 PM, Paolo Bonzini wrote:
> On Tue, Jun 11, 2024 at 3:18 PM Binbin Wu <binbin.wu@...ux.intel.com> wrote:
>>>>    }
>>>>
>>>> diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
>>>> index ed46e7e57c18..4f3b872cd401 100644
>>>> --- a/arch/x86/kvm/vmx/main.c
>>>> +++ b/arch/x86/kvm/vmx/main.c
>>>> @@ -283,6 +283,43 @@ static void vt_msr_filter_changed(struct kvm_vcpu *vcpu)
>>>>       vmx_msr_filter_changed(vcpu);
>>>>    }
>>>>
>>>> +#ifdef CONFIG_KVM_SMM
>>>> +static int vt_smi_allowed(struct kvm_vcpu *vcpu, bool for_injection)
>>>> +{
>>>> +    if (is_td_vcpu(vcpu))
>>>> +            return tdx_smi_allowed(vcpu, for_injection);
>>> Adding stubs for something that TDX will never support is silly.  Bug the VM and
>>> return an error.
>>>
>>>        if (KVM_BUG_ON(is_td_vcpu(vcpu)))
>>>                return -EIO;
>> is_td_vcpu() is defined in tdx.h.
>> Do you mind using open code to check whether the VM is TD in vmx.c?
>> "vcpu->kvm->arch.vm_type == KVM_X86_TDX_VM"
> I'd move it to some place that main.c can see.

is_td_vcpu() can be seen in main.c


>   Or vmx.c as Sean says
> below, but I am not sure I like the idea too much.

Which you may not like? Remove the vt_* wrapper or use KVM_BUG_ON()?

>
> Paolo
>
>>> And I wouldn't even bother with vt_* wrappers, just put that right in vmx_*().
>>> Same thing for everything below.
> If it's a KVM_BUG_ON()
>