Re: [PATCH 2/5] KVM: SVM: hyper-v: Enable Enlightened MSR-Bitmap support for real

Paolo Bonzini
2022-01-25T15:55:57Z

On 12/20/21 16:21, Vitaly Kuznetsov wrote:
> Commit c4327f15dfc7 ("KVM: SVM: hyper-v: Enlightened MSR-Bitmap support")
> introduced enlightened MSR-Bitmap support for KVM-on-Hyper-V but it didn't
> actually enable the support. Similar to enlightened NPT TLB flush and
> direct TLB flush features, the guest (KVM) has to tell L0 (Hyper-V) that
> it's using the feature by setting the appropriate feature fit in VMCB
> control area (sw reserved fields).
>
> Fixes: c4327f15dfc7 ("KVM: SVM: hyper-v: Enlightened MSR-Bitmap support")
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
> arch/x86/kvm/svm/svm_onhyperv.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/x86/kvm/svm/svm_onhyperv.h b/arch/x86/kvm/svm/svm_onhyperv.h
> index cdbcfc63d171..489ca56212c6 100644
> --- a/arch/x86/kvm/svm/svm_onhyperv.h
> +++ b/arch/x86/kvm/svm/svm_onhyperv.h
> @@ -46,6 +46,9 @@ static inline void svm_hv_init_vmcb(struct vmcb *vmcb)
> if (npt_enabled &&
> ms_hyperv.nested_features & HV_X64_NESTED_ENLIGHTENED_TLB)
> hve->hv_enlightenments_control.enlightened_npt_tlb = 1;
> +
> + if (ms_hyperv.nested_features & HV_X64_NESTED_MSR_BITMAP)
> + hve->hv_enlightenments_control.msr_bitmap = 1;
> }
>
> static inline void svm_hv_hardware_setup(void)

Queued this one for now.

Paolo