Sean Christopherson <seanjc@xxxxxxxxxx> 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@xxxxxxxxxx>
> ---
> 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@xxxxxxxxxx>
--
Vitaly
