Vineeth Pillai <viremana@xxxxxxxxxxxxxxxxxxx> writes:
> Enlightened MSR-Bitmap as per TLFS:
>
> "The L1 hypervisor may collaborate with the L0 hypervisor to make MSR
> accesses more efficient. It can enable enlightened MSR bitmaps by setting
> the corresponding field in the enlightened VMCS to 1. When enabled, L0
> hypervisor does not monitor the MSR bitmaps for changes. Instead, the L1
> hypervisor must invalidate the corresponding clean field after making
> changes to one of the MSR bitmaps."
>
> Enable this for SVM.
>
> Related VMX changes:
> commit ceef7d10dfb6 ("KVM: x86: VMX: hyper-v: Enlightened MSR-Bitmap support")
>
> Signed-off-by: Vineeth Pillai <viremana@xxxxxxxxxxxxxxxxxxx>
> ---
> arch/x86/kvm/svm/svm.c | 27 +++++++++++++++++++++++++++
> 1 file changed, 27 insertions(+)
>
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index 6287cab61f15..3562a247b7e8 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -646,6 +646,27 @@ static bool msr_write_intercepted(struct kvm_vcpu *vcpu, u32 msr)
> return !!test_bit(bit_write, &tmp);
> }
>
> +#if IS_ENABLED(CONFIG_HYPERV)
> +static inline void hv_vmcb_dirty_nested_enlightenments(struct kvm_vcpu *vcpu)
> +{
> + struct vmcb *vmcb = to_svm(vcpu)->vmcb;
> +
> + /*
> + * vmcb can be NULL if called during early vcpu init.
> + * And its okay not to mark vmcb dirty during vcpu init
> + * as we mark it dirty unconditionally towards end of vcpu
> + * init phase.
> + */
> + if (vmcb && vmcb_is_clean(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS) &&
> + vmcb->hv_enlightenments.hv_enlightenments_control.msr_bitmap)
> + vmcb_mark_dirty(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS);
vmcb_is_clean() check seems to be superfluous, vmcb_mark_dirty() does no
harm if the bit was already cleared.
> +}
> +#else
> +static inline void hv_vmcb_dirty_nested_enlightenments(struct kvm_vcpu *vcpu)
> +{
> +}
> +#endif
> +
> static void set_msr_interception_bitmap(struct kvm_vcpu *vcpu, u32 *msrpm,
> u32 msr, int read, int write)
> {
> @@ -677,6 +698,9 @@ static void set_msr_interception_bitmap(struct kvm_vcpu *vcpu, u32 *msrpm,
> write ? clear_bit(bit_write, &tmp) : set_bit(bit_write, &tmp);
>
> msrpm[offset] = tmp;
> +
> + hv_vmcb_dirty_nested_enlightenments(vcpu);
> +
> }
>
> void set_msr_interception(struct kvm_vcpu *vcpu, u32 *msrpm, u32 msr,
> @@ -1135,6 +1159,9 @@ static void 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;
> }
> #else
> static inline void hv_init_vmcb(struct vmcb *vmcb)
--
Vitaly
