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

Vitaly Kuznetsov
2021-12-20T15:22:47Z

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)
--
2.33.1