linux-kernel - Re: [PATCH v3 2/4] KVM: SVM: Add emulation support for #GP triggered by SVM instructions

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Message-ID: <99e65d54-8d6b-b027-aa34-66e0e30b5e1f@redhat.com>
Date:   Tue, 26 Jan 2021 12:34:26 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Wei Huang <wei.huang2@....com>, kvm@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, vkuznets@...hat.com,
        mlevitsk@...hat.com, seanjc@...gle.com, joro@...tes.org,
        bp@...en8.de, tglx@...utronix.de, mingo@...hat.com, x86@...nel.org,
        jmattson@...gle.com, wanpengli@...cent.com, bsd@...hat.com,
        dgilbert@...hat.com, luto@...capital.net
Subject: Re: [PATCH v3 2/4] KVM: SVM: Add emulation support for #GP triggered
 by SVM instructions

On 26/01/21 09:18, Wei Huang wrote:
> 
> @@ -288,6 +290,9 @@ int svm_set_efer(struct kvm_vcpu *vcpu, u64 efer)
>  		if (!(efer & EFER_SVME)) {
>  			svm_leave_nested(svm);
>  			svm_set_gif(svm, true);
> +			/* #GP intercept is still needed in vmware_backdoor */
> +			if (!enable_vmware_backdoor)
> +				clr_exception_intercept(svm, GP_VECTOR);
>  
>  			/*
>  			 * Free the nested guest state, unless we are in SMM.
> @@ -309,6 +314,10 @@ int svm_set_efer(struct kvm_vcpu *vcpu, u64 efer)
>  
>  	svm->vmcb->save.efer = efer | EFER_SVME;
>  	vmcb_mark_dirty(svm->vmcb, VMCB_CR);
> +	/* Enable #GP interception for SVM instructions */
> +	if (svm_gp_erratum_intercept)
> +		set_exception_intercept(svm, GP_VECTOR);
> +
>  	return 0;
>  }
>  

This should be in the "if (!(efer & EFER_SVME)) else" branch.  I'll fix 
it up myself.

Paolo