linux-kernel - Re: [PATCH] KVM: nVMX: Fix the NMI IDT-vectoring info handling

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Date:   Thu, 22 Sep 2016 11:37:28 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Wanpeng Li <kernellwp@...il.com>, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Cc:     Wanpeng Li <wanpeng.li@...mail.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Jan Kiszka <jan.kiszka@...mens.com>,
        Bandan Das <bsd@...hat.com>
Subject: Re: [PATCH] KVM: nVMX: Fix the NMI IDT-vectoring info handling



On 22/09/2016 05:34, Wanpeng Li wrote:
> -	if (vmx->rmode.vm86_active) {
> -		if (kvm_inject_realmode_interrupt(vcpu, NMI_VECTOR, 0) != EMULATE_DONE)
> -			kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
> -		return;
> +		++vcpu->stat.nmi_injections;
> +		vmx->nmi_known_unmasked = false;
> +		if (vmx->rmode.vm86_active) {
> +			if (kvm_inject_realmode_interrupt(vcpu, NMI_VECTOR, 0) != EMULATE_DONE)
> +				kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
> +			return;
> +		}
>  	}
>  	vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
>  			INTR_TYPE_NMI_INTR | INTR_INFO_VALID_MASK | NMI_VECTOR);

Hi,

the patch is mostly okay but the "if (vmx->rmode.vm86_active)" part
should be done also if the VCPU is in guest mode.  See
vmx_queue_exception for a similar example.

I would like to know which processors lack virtual NMI support.  I'd
rather rip that code out...

Thanks,

Paolo