linux-kernel - Re: [PATCH 0/3] KVM: x86: Clean up RESET "emulation"

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Date:   Fri, 17 Sep 2021 19:37:21 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm <kvm@...r.kernel.org>,
        "Kernel Mailing List, Linux" <linux-kernel@...r.kernel.org>,
        Reiji Watanabe <reijiw@...gle.com>
Subject: Re: [PATCH 0/3] KVM: x86: Clean up RESET "emulation"

On 17/09/21 19:34, Sean Christopherson wrote:
>> but I do like it so yes, that was it. Especially the fact that init_vmcb now
>> has a single caller. I would further consider moving save area initialization
>> to *_vcpu_reset, and keeping the control fields in init_vmcb/vmcs. That would
>> make it easier to relate the two functions to separate parts of the manuals.
>
> I like the idea, but I think I'd prefer to tackle that at the same time as generic
> support for handling MSRs at RESET/INIT.

No problem, just roughly sketching some ideas for the future.  But 
you're absolutely right that some MSRs have effects on the control areas 
rather than the save area (and some have effects on neither).

Thanks,

Paolo

> E.g. instead of manually writing
> vmcs.GUEST_SYSENTER_* at RESET, provide infrastruture to automagically run through
> all emulated/virtualized at RESET and/or INIT as appropriate to initialize the
> guest value.
>