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References: <20210412130938.68178-1-david.edmondson@oracle.com>
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From:   Jim Mattson <jmattson@google.com>
Date:   Mon, 12 Apr 2021 11:34:33 -0700
Message-ID: <CALMp9eRTy-m6DkXRSGNU=r7xmrzFFQU60DB2asUDZLCgw93wRQ@mail.gmail.com>
Subject: Re: [PATCH 0/6] KVM: x86: Make the cause of instruction emulation
 available to user-space
To:     David Edmondson <david.edmondson@oracle.com>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        kvm list <kvm@vger.kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
        "the arch/x86 maintainers" <x86@kernel.org>,
        Sean Christopherson <seanjc@google.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Joerg Roedel <joro@8bytes.org>,
        Wanpeng Li <wanpengli@tencent.com>,
        Borislav Petkov <bp@alien8.de>, Ingo Molnar <mingo@redhat.com>,
        Aaron Lewis <aaronlewis@google.com>
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On Mon, Apr 12, 2021 at 6:09 AM David Edmondson
<david.edmondson@oracle.com> wrote:
>
> Instruction emulation happens for a variety of reasons, yet on error
> we have no idea exactly what triggered it. Add a cause of emulation to
> the various originators and pass it upstream when emulation fails.

What is userspace going to do with this information? It's hard to say
whether or not this is the right ABI without more context.