linux-kernel - Re: [PATCH 1/4] KVM: x86: mark synthetic SMM vmexit as SVM_EXIT

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Message-ID: <da421a98-cca2-aece-b3a2-eb83e9795801@redhat.com>
Date:   Wed, 9 Mar 2022 16:46:50 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Maxim Levitsky <mlevitsk@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>
Cc:     kvm@...r.kernel.org, Jim Mattson <jmattson@...gle.com>,
        "H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Borislav Petkov <bp@...en8.de>, x86@...nel.org
Subject: Re: [PATCH 1/4] KVM: x86: mark synthetic SMM vmexit as SVM_EXIT_SW

On 3/1/22 18:13, Maxim Levitsky wrote:
> The fact that we have a stale VM exit reason in vmcb without this
> patch which can be in theory consumed somewhere down the road.
> 
> This stale vm exit reason also appears in the tracs which is
> very misleading.

Let's put it in the commit message:

This makes it a bit easier to read the KVM trace, and avoids
other potential problems due to a stale vmexit reason in the vmcb.  If
SVM_EXIT_SW somehow reaches svm_invoke_exit_handler(), instead, 
svm_check_exit_valid() will return false and a WARN will be logged.

Paolo