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References: <20220322110712.222449-1-pbonzini@redhat.com> <20220322110712.222449-3-pbonzini@redhat.com>
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From:   Jim Mattson <jmattson@google.com>
Date:   Wed, 23 Mar 2022 09:59:55 -0700
Message-ID: <CALMp9eS0_BXC2J26umCOqQS6mbZn-QKQqYzFcON5rrEBbebbvw@mail.gmail.com>
Subject: Re: [PATCH 2/3] Documentation: KVM: add virtual CPU errata documentation
To:     Paolo Bonzini <pbonzini@redhat.com>
Cc:     linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        mlevitsk@redhat.com
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On Tue, Mar 22, 2022 at 4:07 AM Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> Add a file to document all the different ways in which the virtual CPU
> emulation is imperfect.  Include an example to show how to document
> such errata.
This is fantastic. Thank you. Along these lines, I wonder if we should
come up with a mechanism a la IA32_ARCH_CAPABILITIES (or AMD's OSVW
MSRs) for declaring fixed errata.

For example, today, KVM ignores the guest-only and host-only bits in
PerfEvtSel MSRs, but I can't imagine we're going to do that forever.

Reviewed-by: Jim Mattson <jmattson@google.com>