linux-kernel - Re: [RFC PATCH v3 28/59] KVM: x86: Check for pending APICv interrupt in kvm_vcpu_has

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Message-ID: <4708e92c-373b-a07f-c80c-fe194ca706df@redhat.com>
Date:   Thu, 25 Nov 2021 21:50:39 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     isaku.yamahata@...el.com, Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, erdemaktas@...gle.com,
        Connor Kuehl <ckuehl@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     isaku.yamahata@...il.com,
        Sean Christopherson <sean.j.christopherson@...el.com>
Subject: Re: [RFC PATCH v3 28/59] KVM: x86: Check for pending APICv interrupt
 in kvm_vcpu_has_events()

On 11/25/21 01:20, isaku.yamahata@...el.com wrote:
> From: Sean Christopherson<sean.j.christopherson@...el.com>
> 
> Return true for kvm_vcpu_has_events() if the vCPU has a pending APICv
> interrupt to support TDX's usage of APICv.  Unlike VMX, TDX doesn't have
> access to vmcs.GUEST_INTR_STATUS and so can't emulate posted interrupts,
> i.e. needs to generate a posted interrupt and more importantly can't
> manually move requested interrupts into the vIRR (which it also doesn't
> have access to).

Does this mean it is impossible to disable APICv on TDX?  If so, please 
add a WARN.

Paolo