From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH v2 6/6] KVM: nVMX: optimize prepare_vmcs02{,_full} for
 Enlightened VMCS case
Date: Wed, 25 Jul 2018 15:31:47 +0200
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Cc: kvm@vger.kernel.org,
        =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        Roman Kagan <rkagan@virtuozzo.com>,
        "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
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        Mohammed Gamal <mmorsy@redhat.com>,
        Cathy Avery <cavery@redhat.com>, linux-kernel@vger.kernel.org,
        Jim Mattson <jmattson@google.com>,
        Liran Alon <liran.alon@oracle.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>
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On 25/07/2018 15:26, Vitaly Kuznetsov wrote:
> Doing it in nested_vmx_handle_enlightened_vmptrld() is even better: we
> can simplify copy_enlightened_to_vmcs12() too!

Yes, that's true!

> The other place where we set dirty_vmcs12 is the newly introduced
> vmx_set_nested_state() but I think I'm going to add support for eVMCS
> there later and just return something like -ENOTSUPP for now. Too many
> people work on nested simultaneously :-)

Hmm, I think that means you have to put the clean fields in the
vmx_nested struct.  Then it's really easy in vmx_set_nested_state to
clear all the clean bits.  Touching memory in vmx_set_nested_state is...
*puts on sunglasses* a touchy subject (see comment in kvm/queue's
enter_vmx_non_root_mode).

Thanks,

Paolo