Messages in this thread | | | From | Vitaly Kuznetsov <> | Subject | Re: [PATCH 09/22] KVM: x86: Uninline and export hv_track_root_tdp() | Date | Mon, 31 Jan 2022 17:19:44 +0100 |
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Sean Christopherson <seanjc@google.com> writes:
> Uninline and export Hyper-V's hv_track_root_tdp(), which is (somewhat > indirectly) the last remaining reference to kvm_x86_ops from vendor > modules, i.e. will allow unexporting kvm_x86_ops. Reloading the TDP PGD > isn't the fastest of paths, hv_track_root_tdp() isn't exactly tiny, and > disallowing vendor code from accessing kvm_x86_ops provides nice-to-have > encapsulation of common x86 code (and of Hyper-V code for that > matter).
We can add a static branch for "kvm_x86_ops.tlb_remote_flush == hv_remote_flush_tlb" condition and check it in vendor modules prior to calling into hv_track_root_tdp() but I seriously doubt it'll bring us noticable performance gain.
> > No functional change intended. > > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > arch/x86/kvm/kvm_onhyperv.c | 14 ++++++++++++++ > arch/x86/kvm/kvm_onhyperv.h | 14 +------------- > 2 files changed, 15 insertions(+), 13 deletions(-) > > diff --git a/arch/x86/kvm/kvm_onhyperv.c b/arch/x86/kvm/kvm_onhyperv.c > index b469f45e3fe4..ee4f696a0782 100644 > --- a/arch/x86/kvm/kvm_onhyperv.c > +++ b/arch/x86/kvm/kvm_onhyperv.c > @@ -92,3 +92,17 @@ int hv_remote_flush_tlb(struct kvm *kvm) > return hv_remote_flush_tlb_with_range(kvm, NULL); > } > EXPORT_SYMBOL_GPL(hv_remote_flush_tlb); > + > +void hv_track_root_tdp(struct kvm_vcpu *vcpu, hpa_t root_tdp) > +{ > + struct kvm_arch *kvm_arch = &vcpu->kvm->arch; > + > + if (kvm_x86_ops.tlb_remote_flush == hv_remote_flush_tlb) { > + spin_lock(&kvm_arch->hv_root_tdp_lock); > + vcpu->arch.hv_root_tdp = root_tdp; > + if (root_tdp != kvm_arch->hv_root_tdp) > + kvm_arch->hv_root_tdp = INVALID_PAGE; > + spin_unlock(&kvm_arch->hv_root_tdp_lock); > + } > +} > +EXPORT_SYMBOL_GPL(hv_track_root_tdp); > diff --git a/arch/x86/kvm/kvm_onhyperv.h b/arch/x86/kvm/kvm_onhyperv.h > index 1c67abf2eba9..287e98ef9df3 100644 > --- a/arch/x86/kvm/kvm_onhyperv.h > +++ b/arch/x86/kvm/kvm_onhyperv.h > @@ -10,19 +10,7 @@ > int hv_remote_flush_tlb_with_range(struct kvm *kvm, > struct kvm_tlb_range *range); > int hv_remote_flush_tlb(struct kvm *kvm); > - > -static inline void hv_track_root_tdp(struct kvm_vcpu *vcpu, hpa_t root_tdp) > -{ > - struct kvm_arch *kvm_arch = &vcpu->kvm->arch; > - > - if (kvm_x86_ops.tlb_remote_flush == hv_remote_flush_tlb) { > - spin_lock(&kvm_arch->hv_root_tdp_lock); > - vcpu->arch.hv_root_tdp = root_tdp; > - if (root_tdp != kvm_arch->hv_root_tdp) > - kvm_arch->hv_root_tdp = INVALID_PAGE; > - spin_unlock(&kvm_arch->hv_root_tdp_lock); > - } > -} > +void hv_track_root_tdp(struct kvm_vcpu *vcpu, hpa_t root_tdp); > #else /* !CONFIG_HYPERV */ > static inline void hv_track_root_tdp(struct kvm_vcpu *vcpu, hpa_t root_tdp) > {
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
-- Vitaly
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