On Wed, Sep 21, 2022 at 10:35:38AM -0700,
David Matlack <dmatlack@xxxxxxxxxx> wrote:
> Move kvm_mmu_{init,uninit}_tdp_mmu() behind tdp_mmu_enabled. This makes
> these functions consistent with the rest of the calls into the TDP MMU
> from mmu.c, and which is now possible since tdp_mmu_enabled is only
> modified when the x86 vendor module is loaded. i.e. It will never change
> during the lifetime of a VM.
>
> This change also enabled removing the stub definitions for 32-bit KVM,
> as the compiler will just optimize the calls out like it does for all
> the other TDP MMU functions.
>
> No functional change intended.
>
> Signed-off-by: David Matlack <dmatlack@xxxxxxxxxx>
> ---
> arch/x86/kvm/mmu/mmu.c | 11 +++++++----
> arch/x86/kvm/mmu/tdp_mmu.c | 6 ------
> arch/x86/kvm/mmu/tdp_mmu.h | 7 +++----
> 3 files changed, 10 insertions(+), 14 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index ccb0b18fd194..dd261cd2ad4e 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -5970,9 +5970,11 @@ int kvm_mmu_init_vm(struct kvm *kvm)
> INIT_LIST_HEAD(&kvm->arch.lpage_disallowed_mmu_pages);
> spin_lock_init(&kvm->arch.mmu_unsync_pages_lock);
>
> - r = kvm_mmu_init_tdp_mmu(kvm);
> - if (r < 0)
> - return r;
> + if (tdp_mmu_enabled) {
> + r = kvm_mmu_init_tdp_mmu(kvm);
> + if (r < 0)
> + return r;
> + }
>
> node->track_write = kvm_mmu_pte_write;
> node->track_flush_slot = kvm_mmu_invalidate_zap_pages_in_memslot;
> @@ -6002,7 +6004,8 @@ void kvm_mmu_uninit_vm(struct kvm *kvm)
>
> kvm_page_track_unregister_notifier(kvm, node);
>
> - kvm_mmu_uninit_tdp_mmu(kvm);
> + if (tdp_mmu_enabled)
> + kvm_mmu_uninit_tdp_mmu(kvm);
>
> mmu_free_vm_memory_caches(kvm);
> }
> diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
> index e7d0f21fbbe8..08ab3596dfaa 100644
> --- a/arch/x86/kvm/mmu/tdp_mmu.c
> +++ b/arch/x86/kvm/mmu/tdp_mmu.c
> @@ -15,9 +15,6 @@ int kvm_mmu_init_tdp_mmu(struct kvm *kvm)
> {
> struct workqueue_struct *wq;
>
> - if (!tdp_mmu_enabled)
> - return 0;
> -
> wq = alloc_workqueue("kvm", WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE, 0);
> if (!wq)
> return -ENOMEM;
> @@ -43,9 +40,6 @@ static __always_inline bool kvm_lockdep_assert_mmu_lock_held(struct kvm *kvm,
>
> void kvm_mmu_uninit_tdp_mmu(struct kvm *kvm)
> {
> - if (!tdp_mmu_enabled)
> - return;
> -
> /* Also waits for any queued work items. */
> destroy_workqueue(kvm->arch.tdp_mmu_zap_wq);
>
> diff --git a/arch/x86/kvm/mmu/tdp_mmu.h b/arch/x86/kvm/mmu/tdp_mmu.h
> index c163f7cc23ca..9d086a103f77 100644
> --- a/arch/x86/kvm/mmu/tdp_mmu.h
> +++ b/arch/x86/kvm/mmu/tdp_mmu.h
> @@ -5,6 +5,9 @@
>
> #include <linux/kvm_host.h>
>
> +int kvm_mmu_init_tdp_mmu(struct kvm *kvm);
> +void kvm_mmu_uninit_tdp_mmu(struct kvm *kvm);
> +
> hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu);
>
> __must_check static inline bool kvm_tdp_mmu_get_root(struct kvm_mmu_page *root)
> @@ -66,8 +69,6 @@ u64 *kvm_tdp_mmu_fast_pf_get_last_sptep(struct kvm_vcpu *vcpu, u64 addr,
> u64 *spte);
>
> #ifdef CONFIG_X86_64
> -int kvm_mmu_init_tdp_mmu(struct kvm *kvm);
> -void kvm_mmu_uninit_tdp_mmu(struct kvm *kvm);
> static inline bool is_tdp_mmu_page(struct kvm_mmu_page *sp) { return sp->tdp_mmu_page; }
>
> static inline bool is_tdp_mmu(struct kvm_mmu *mmu)
> @@ -87,8 +88,6 @@ static inline bool is_tdp_mmu(struct kvm_mmu *mmu)
> return sp && is_tdp_mmu_page(sp) && sp->root_count;
> }
> #else
> -static inline int kvm_mmu_init_tdp_mmu(struct kvm *kvm) { return 0; }
> -static inline void kvm_mmu_uninit_tdp_mmu(struct kvm *kvm) {}
> static inline bool is_tdp_mmu_page(struct kvm_mmu_page *sp) { return false; }
> static inline bool is_tdp_mmu(struct kvm_mmu *mmu) { return false; }
> #endif
> --
> 2.37.3.998.g577e59143f-goog
Reviewed-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
--
Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
