Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20220627160440.31857-1-vkuznets@redhat.com>
In-Reply-To: <20220627160440.31857-1-vkuznets@redhat.com>
From:   Jim Mattson <jmattson@google.com>
Date:   Mon, 27 Jun 2022 10:50:22 -0700
Message-ID: <CALMp9eQL2a+mStk-cLwVX6NVqwAso2UYxAO7UD=Xi2TSGwUM2A@mail.gmail.com>
Subject: Re: [PATCH 00/14] KVM: nVMX: Use vmcs_config for setting up nested
 VMX MSRs
To:     Vitaly Kuznetsov <vkuznets@redhat.com>
Cc:     kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        Anirudh Rayabharam <anrayabh@linux.microsoft.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Maxim Levitsky <mlevitsk@redhat.com>,
        linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Mon, Jun 27, 2022 at 9:04 AM Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>
> Changes since RFC:
> - "KVM: VMX: Extend VMX controls macro shenanigans" PATCH added and the
>   infrastructure is later used in other patches [Sean] PATCHes 1-3 added
>   to support the change.
> - "KVM: VMX: Clear controls obsoleted by EPT at runtime, not setup" PATCH
>   added [Sean].
> - Commit messages added.
>
> vmcs_config is a sanitized version of host VMX MSRs where some controls are
> filtered out (e.g. when Enlightened VMCS is enabled, some know bugs are
> discovered, some inconsistencies in controls are detected,...) but
> nested_vmx_setup_ctls_msrs() uses raw host MSRs instead. This may end up
> in exposing undesired controls to L1. Switch to using vmcs_config instead.
>
> Sean Christopherson (1):
>   KVM: VMX: Clear controls obsoleted by EPT at runtime, not setup
>
> Vitaly Kuznetsov (13):
>   KVM: VMX: Check VM_ENTRY_IA32E_MODE in setup_vmcs_config()
>   KVM: VMX: Check CPU_BASED_{INTR,NMI}_WINDOW_EXITING in
>     setup_vmcs_config()
>   KVM: VMX: Tweak the special handling of SECONDARY_EXEC_ENCLS_EXITING
>     in setup_vmcs_config()
>   KVM: VMX: Extend VMX controls macro shenanigans
>   KVM: VMX: Move CPU_BASED_CR8_{LOAD,STORE}_EXITING filtering out of
>     setup_vmcs_config()
>   KVM: VMX: Add missing VMEXIT controls to vmcs_config
>   KVM: VMX: Add missing VMENTRY controls to vmcs_config
>   KVM: VMX: Add missing CPU based VM execution controls to vmcs_config
>   KVM: nVMX: Use sanitized allowed-1 bits for VMX control MSRs
>   KVM: VMX: Store required-1 VMX controls in vmcs_config
>   KVM: nVMX: Use sanitized required-1 bits for VMX control MSRs
>   KVM: VMX: Cache MSR_IA32_VMX_MISC in vmcs_config
>   KVM: nVMX: Use cached host MSR_IA32_VMX_MISC value for setting up
>     nested MSR
>
>  arch/x86/kvm/vmx/capabilities.h |  16 +--
>  arch/x86/kvm/vmx/nested.c       |  37 +++---
>  arch/x86/kvm/vmx/nested.h       |   2 +-
>  arch/x86/kvm/vmx/vmx.c          | 198 ++++++++++++++------------------
>  arch/x86/kvm/vmx/vmx.h          | 118 +++++++++++++++++++
>  5 files changed, 229 insertions(+), 142 deletions(-)
>
> --
> 2.35.3
>

Just checking that this doesn't introduce any backwards-compatibility
issues. That is, all features that were reported as being available in
the past should still be available moving forward.

Thanks,

--jim