linux-kernel - Re: [PATCH v6 06/13] KVM: nVMX: optimize prepare_vmcs02{,

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Message-ID: <fc7d9a2c-6cf8-751e-9e0b-b9bbe0bddf5d@redhat.com>
Date:   Thu, 18 Oct 2018 14:42:33 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        Jim Mattson <jmattson@...gle.com>
Cc:     Radim Krčmář <rkrcmar@...hat.com>,
        Roman Kagan <rkagan@...tuozzo.com>,
        "K. Y. Srinivasan" <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        "Michael Kelley (EOSG)" <Michael.H.Kelley@...rosoft.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Liran Alon <liran.alon@...cle.com>,
        kvm list <kvm@...r.kernel.org>
Subject: Re: [PATCH v6 06/13] KVM: nVMX: optimize prepare_vmcs02{,_full} for
 Enlightened VMCS case

On 18/10/2018 13:14, Vitaly Kuznetsov wrote:
> 
> Based on that my suggestion would be to shadow GUEST_SS_AR_BYTES, keep
> GUEST_SS_AR_BYTES and unshadow the rest (GUEST_ES_BASE,
> GUEST_CS_SELECTOR, GUEST_CS_LIMIT, GUEST_CS_BASE). I can do this as a
> separate patch as I see this series is already in kvm/queue.

Yes, it should be a separate patch anyway.

GUEST_CS_BASE and GUEST_CS_LIMIT probably matter for 32-bit guests, but
I guess it's okay to remove them.  GUEST_CS_SELECTOR probably dates back
to when we were incorrectly using CPL=CS.RPL instead of CPL=SS.DPL, and
can be removed too.

GUEST_ES_BASE alone is quite useless, so it can go.

Paolo