Re: [PATCH 0/5] KVM: SVM: nSVM: Implement Enlightened MSR-Bitmap for Hyper-V-on-KVM and fix it for KVM-on-Hyper-V

[Paolo Bonzini]

On 12/20/21 16:21, Vitaly Kuznetsov wrote:
> Enlightened MSR-Bitmap feature implements a PV protocol for L0 and L1
> hypervisors to collaborate and skip unneeded updates to MSR-Bitmap.
> KVM implements the feature for KVM-on-Hyper-V but it seems there was
> a flaw in the implementation and the feature may not be fully functional.
> PATCHes 1-2 fix the problem. The rest of the series implements the same
> feature for Hyper-V-on-KVM.
>
> Vitaly Kuznetsov (5):
>    KVM: SVM: Drop stale comment from
>      svm_hv_vmcb_dirty_nested_enlightenments()
>    KVM: SVM: hyper-v: Enable Enlightened MSR-Bitmap support for real
>    KVM: nSVM: Track whether changes in L0 require MSR bitmap for L2 to be
>      rebuilt
>    KVM: x86: Make kvm_hv_hypercall_enabled() static inline
>    KVM: nSVM: Implement Enlightened MSR-Bitmap feature
>
>   arch/x86/kvm/hyperv.c           | 12 +--------
>   arch/x86/kvm/hyperv.h           |  6 ++++-
>   arch/x86/kvm/svm/nested.c       | 47 ++++++++++++++++++++++++++++-----
>   arch/x86/kvm/svm/svm.c          |  3 ++-
>   arch/x86/kvm/svm/svm.h          | 16 +++++++----
>   arch/x86/kvm/svm/svm_onhyperv.h | 12 +++------
>   6 files changed, 63 insertions(+), 33 deletions(-)

Queued 3-5 now, but it would be nice to have some testcases.

Paolo