From: Sean Christopherson <seanjc@google.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>,
Maxim Levitsky <mlevitsk@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 3/4] KVM: nVMX: Track whether changes in L0 require MSR bitmap for L2 to be rebuilt
Date: Fri, 5 Nov 2021 14:28:25 +0000 [thread overview]
Message-ID: <YYU/iQCQJosjTKVs@google.com> (raw)
In-Reply-To: <875yt6lscj.fsf@vitty.brq.redhat.com>
On Fri, Nov 05, 2021, Vitaly Kuznetsov wrote:
> Sean Christopherson <seanjc@google.com> writes:
>
> > On Wed, Oct 13, 2021, Vitaly Kuznetsov wrote:
> >> diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
> >> index 592217fd7d92..2cdf66e6d1b0 100644
> >> --- a/arch/x86/kvm/vmx/vmx.h
> >> +++ b/arch/x86/kvm/vmx/vmx.h
> >> @@ -148,6 +148,15 @@ struct nested_vmx {
> >> bool need_vmcs12_to_shadow_sync;
> >> bool dirty_vmcs12;
> >>
> >> + /*
> >> + * Indicates whether MSR bitmap for L2 needs to be rebuilt due to
> >> + * changes in MSR bitmap for L1 or switching to a different L2. Note,
> >> + * this flag can only be used reliably in conjunction with a paravirt L1
> >> + * which informs L0 whether any changes to MSR bitmap for L2 were done
> >> + * on its side.
> >> + */
> >> + bool msr_bitmap_force_recalc;
> >
> > Belated bikeshedding... What about need_msr_bitmap_recalc to follow the above
> > need_vmcs12_to_shadow_sync?
> >
>
> 'msr_bitmap_force_recalc' was suggested by Paolo but
> 'need_msr_bitmap_recalc' sounds equally good to me.
Ah, actually, Paolo's is better. "!need" implies that the recalc can be skipped
regardless of any other behavior, whereas "!force" provides the hint that a recalc
may still be needed for other reasons.
Can we move the "force" to the front though, i.e. force_msr_bitmap_recalc? The
other fields in nested_vmx all have the verb at the front.
bool need_vmcs12_to_shadow_sync;
bool need_sync_vmcs02_to_vmcs12_rare;
bool change_vmcs01_virtual_apic_mode;
bool reload_vmcs01_apic_access_page;
bool update_vmcs01_cpu_dirty_logging;
next prev parent reply other threads:[~2021-11-05 14:28 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-13 14:22 [PATCH v3 0/4] KVM: nVMX: Enlightened MSR Bitmap feature for Hyper-V on KVM Vitaly Kuznetsov
2021-10-13 14:22 ` [PATCH v3 1/4] KVM: nVMX: Don't use Enlightened MSR Bitmap for L3 Vitaly Kuznetsov
2021-11-05 0:52 ` Sean Christopherson
2021-11-05 12:03 ` Vitaly Kuznetsov
2021-11-05 15:38 ` Maxim Levitsky
2021-11-05 15:39 ` Maxim Levitsky
2021-10-13 14:22 ` [PATCH v3 2/4] KVM: VMX: Introduce vmx_msr_bitmap_l01_changed() helper Vitaly Kuznetsov
2021-11-05 1:00 ` Sean Christopherson
2021-10-13 14:22 ` [PATCH v3 3/4] KVM: nVMX: Track whether changes in L0 require MSR bitmap for L2 to be rebuilt Vitaly Kuznetsov
2021-11-05 1:05 ` Sean Christopherson
2021-11-05 12:06 ` Vitaly Kuznetsov
2021-11-05 14:28 ` Sean Christopherson [this message]
2021-10-13 14:22 ` [PATCH v3 4/4] KVM: nVMX: Implement Enlightened MSR Bitmap feature Vitaly Kuznetsov
2021-11-05 1:09 ` Sean Christopherson
2021-11-05 12:08 ` Vitaly Kuznetsov
2021-11-03 15:13 ` [PATCH v3 0/4] KVM: nVMX: Enlightened MSR Bitmap feature for Hyper-V on KVM Vitaly Kuznetsov
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