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From: Yan Zhao <yan.y.zhao@intel.com>
To: Sean Christopherson <seanjc@google.com>
Cc: kvm@vger.kernel.org, intel-gfx@lists.freedesktop.org,
	linux-kernel@vger.kernel.org, Ben Gardon <bgardon@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	intel-gvt-dev@lists.freedesktop.org
Subject: Re: [Intel-gfx] [PATCH 19/27] KVM: x86/mmu: Use page-track notifiers iff there are external users
Date: Wed, 28 Dec 2022 14:56:00 +0800	[thread overview]
Message-ID: <Y6vogAvkktOPLwK9@yzhao56-desk.sh.intel.com> (raw)
In-Reply-To: <20221223005739.1295925-20-seanjc@google.com>

On Fri, Dec 23, 2022 at 12:57:31AM +0000, Sean Christopherson wrote:
> Disable the page-track notifier code at compile time if there are no
> external users, i.e. if CONFIG_KVM_EXTERNAL_WRITE_TRACKING=n.  KVM itself
> now hooks emulated writes directly instead of relying on the page-track
> mechanism.
> 
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
>  arch/x86/include/asm/kvm_host.h       |  2 ++
>  arch/x86/include/asm/kvm_page_track.h |  2 ++
>  arch/x86/kvm/mmu/page_track.c         |  9 ++++----
>  arch/x86/kvm/mmu/page_track.h         | 30 +++++++++++++++++++++++----
>  4 files changed, 35 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index eec424fac0ba..e8f8e1bd96c7 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1223,7 +1223,9 @@ struct kvm_arch {
>  	 * create an NX huge page (without hanging the guest).
>  	 */
>  	struct list_head possible_nx_huge_pages;
> +#ifdef CONFIG_KVM_EXTERNAL_WRITE_TRACKING
>  	struct kvm_page_track_notifier_head track_notifier_head;
> +#endif
>  	/*
>  	 * Protects marking pages unsync during page faults, as TDP MMU page
>  	 * faults only take mmu_lock for read.  For simplicity, the unsync
> diff --git a/arch/x86/include/asm/kvm_page_track.h b/arch/x86/include/asm/kvm_page_track.h
> index deece45936a5..53c2adb25a07 100644
> --- a/arch/x86/include/asm/kvm_page_track.h
> +++ b/arch/x86/include/asm/kvm_page_track.h
> @@ -55,6 +55,7 @@ void kvm_slot_page_track_remove_page(struct kvm *kvm,
>  				     struct kvm_memory_slot *slot, gfn_t gfn,
>  				     enum kvm_page_track_mode mode);
>  
> +#ifdef CONFIG_KVM_EXTERNAL_WRITE_TRACKING
>  enum pg_level kvm_page_track_max_mapping_level(struct kvm *kvm, gfn_t gfn,
>  					       enum pg_level max_level);
>  
> @@ -64,5 +65,6 @@ kvm_page_track_register_notifier(struct kvm *kvm,
>  void
>  kvm_page_track_unregister_notifier(struct kvm *kvm,
>  				   struct kvm_page_track_notifier_node *n);
> +#endif /* CONFIG_KVM_EXTERNAL_WRITE_TRACKING */
>  
>  #endif
> diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c
> index 2b302fd2c5dd..f932909aa9b5 100644
> --- a/arch/x86/kvm/mmu/page_track.c
> +++ b/arch/x86/kvm/mmu/page_track.c
> @@ -193,6 +193,7 @@ bool kvm_slot_page_track_is_active(struct kvm *kvm,
>  	return !!READ_ONCE(slot->arch.gfn_track[mode][index]);
>  }
>  
> +#ifdef CONFIG_KVM_EXTERNAL_WRITE_TRACKING
>  void kvm_page_track_cleanup(struct kvm *kvm)
>  {
>  	struct kvm_page_track_notifier_head *head;
> @@ -208,6 +209,7 @@ int kvm_page_track_init(struct kvm *kvm)
>  	head = &kvm->arch.track_notifier_head;
>  	INIT_HLIST_HEAD(&head->track_notifier_list);
>  	return init_srcu_struct(&head->track_srcu);
> +	return 0;
Double "return"s.


>  }
>  
>  /*
> @@ -254,8 +256,8 @@ EXPORT_SYMBOL_GPL(kvm_page_track_unregister_notifier);
>   * The node should figure out if the written page is the one that node is
>   * interested in by itself.
>   */
> -void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
> -			  int bytes)
> +void __kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
> +			    int bytes)
>  {
>  	struct kvm_page_track_notifier_head *head;
>  	struct kvm_page_track_notifier_node *n;
> @@ -272,8 +274,6 @@ void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
>  		if (n->track_write)
>  			n->track_write(gpa, new, bytes, n);
>  	srcu_read_unlock(&head->track_srcu, idx);
> -
> -	kvm_mmu_track_write(vcpu, gpa, new, bytes);
>  }
>  
>  /*
> @@ -316,3 +316,4 @@ enum pg_level kvm_page_track_max_mapping_level(struct kvm *kvm, gfn_t gfn,
>  	return max_level;
>  }
>  EXPORT_SYMBOL_GPL(kvm_page_track_max_mapping_level);
> +#endif
> diff --git a/arch/x86/kvm/mmu/page_track.h b/arch/x86/kvm/mmu/page_track.h
> index 89712f123ad3..1b363784aa4a 100644
> --- a/arch/x86/kvm/mmu/page_track.h
> +++ b/arch/x86/kvm/mmu/page_track.h
> @@ -6,8 +6,6 @@
>  
>  #include <asm/kvm_page_track.h>
>  
> -int kvm_page_track_init(struct kvm *kvm);
> -void kvm_page_track_cleanup(struct kvm *kvm);
>  
>  bool kvm_page_track_write_tracking_enabled(struct kvm *kvm);
>  int kvm_page_track_write_tracking_alloc(struct kvm_memory_slot *slot);
> @@ -21,13 +19,37 @@ bool kvm_slot_page_track_is_active(struct kvm *kvm,
>  				   const struct kvm_memory_slot *slot,
>  				   gfn_t gfn, enum kvm_page_track_mode mode);
>  
> -void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
> -			  int bytes);
> +#ifdef CONFIG_KVM_EXTERNAL_WRITE_TRACKING
> +int kvm_page_track_init(struct kvm *kvm);
> +void kvm_page_track_cleanup(struct kvm *kvm);
> +
> +void __kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
> +			    int bytes);
>  void kvm_page_track_delete_slot(struct kvm *kvm, struct kvm_memory_slot *slot);
>  
>  static inline bool kvm_page_track_has_external_user(struct kvm *kvm)
>  {
>  	return hlist_empty(&kvm->arch.track_notifier_head.track_notifier_list);
>  }
> +#else
> +static inline int kvm_page_track_init(struct kvm *kvm) { return 0; }
> +static inline void kvm_page_track_cleanup(struct kvm *kvm) { }
> +
> +static inline void __kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa,
> +					  const u8 *new, int bytes) { }
> +static inline void kvm_page_track_delete_slot(struct kvm *kvm,
> +					      struct kvm_memory_slot *slot) { }
> +
> +static inline bool kvm_page_track_has_external_user(struct kvm *kvm) { return false; }
> +
> +#endif /* CONFIG_KVM_EXTERNAL_WRITE_TRACKING */
> +
> +static inline void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa,
> +					const u8 *new, int bytes)
> +{
> +	__kvm_page_track_write(vcpu, gpa, new, bytes);
> +
Why not convert "vcpu" to "kvm" in __kvm_page_track_write() ?
i.e.
void __kvm_page_track_write(struct kvm *kvm, gpa_t gpa, const u8 *new, int bytes);


Thanks
Yan

> +	kvm_mmu_track_write(vcpu, gpa, new, bytes);
> +}
>  
>  #endif /* __KVM_X86_PAGE_TRACK_H */
> -- 
> 2.39.0.314.g84b9a713c41-goog
> 

  reply	other threads:[~2022-12-28  7:19 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-23  0:57 [Intel-gfx] [PATCH 00/27] drm/i915/gvt: KVM: KVMGT fixes and page-track cleanups Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 01/27] drm/i915/gvt: Verify pfn is "valid" before dereferencing "struct page" Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 02/27] KVM: x86/mmu: Factor out helper to get max mapping size of a memslot Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 03/27] drm/i915/gvt: Incorporate KVM memslot info into check for 2MiB GTT entry Sean Christopherson
2022-12-28  5:42   ` Yan Zhao
2023-01-03 21:13     ` Sean Christopherson
2023-01-05  3:07       ` Yan Zhao
2023-01-05 17:40         ` Sean Christopherson
2023-01-06  5:56           ` Yan Zhao
2023-01-06 23:01             ` Sean Christopherson
2023-01-09  9:58               ` Yan Zhao
2023-01-11 17:55                 ` Sean Christopherson
2023-01-19  2:58                   ` Zhenyu Wang
2023-01-19  5:26                     ` Yan Zhao
2023-02-23 20:41                       ` Sean Christopherson
2023-02-24  5:09                         ` Yan Zhao
2023-01-12  8:31         ` Yan Zhao
2022-12-23  0:57 ` [Intel-gfx] [PATCH 04/27] drm/i915/gvt: Verify VFIO-pinned page is THP when shadowing 2M gtt entry Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 05/27] drm/i915/gvt: Put the page reference obtained by KVM's gfn_to_pfn() Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 06/27] drm/i915/gvt: Don't rely on KVM's gfn_to_pfn() to query possible 2M GTT Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 07/27] drm/i915/gvt: Use an "unsigned long" to iterate over memslot gfns Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 08/27] drm/i915/gvt: Hoist acquisition of vgpu_lock out to kvmgt_page_track_write() Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 09/27] drm/i915/gvt: Protect gfn hash table with dedicated mutex Sean Christopherson
2022-12-28  5:03   ` Yan Zhao
2023-01-03 20:43     ` Sean Christopherson
2023-01-05  0:51       ` Yan Zhao
2022-12-23  0:57 ` [Intel-gfx] [PATCH 10/27] KVM: x86/mmu: Don't rely on page-track mechanism to flush on memslot change Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 11/27] KVM: x86/mmu: Don't bounce through page-track mechanism for guest PTEs Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 12/27] KVM: drm/i915/gvt: Drop @vcpu from KVM's ->track_write() hook Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 13/27] KVM: x86: Reject memslot MOVE operations if KVMGT is attached Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 14/27] drm/i915/gvt: Don't bother removing write-protection on to-be-deleted slot Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 15/27] KVM: x86: Add a new page-track hook to handle memslot deletion Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 16/27] drm/i915/gvt: switch from ->track_flush_slot() to ->track_remove_region() Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 17/27] KVM: x86: Remove the unused page-track hook track_flush_slot() Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 18/27] KVM: x86/mmu: Move KVM-only page-track declarations to internal header Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 19/27] KVM: x86/mmu: Use page-track notifiers iff there are external users Sean Christopherson
2022-12-28  6:56   ` Yan Zhao [this message]
2023-01-04  0:50     ` Sean Christopherson
2023-08-07 12:01   ` Like Xu
2023-08-07 17:19     ` Sean Christopherson
2023-08-09  1:02       ` Yan Zhao
2023-08-09 14:33         ` Sean Christopherson
2023-08-09 23:21           ` Yan Zhao
2023-08-10  3:02             ` Yan Zhao
2023-08-10 15:41               ` Sean Christopherson
2023-08-11  5:57                 ` Yan Zhao
2022-12-23  0:57 ` [Intel-gfx] [PATCH 20/27] KVM: x86/mmu: Drop infrastructure for multiple page-track modes Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 21/27] KVM: x86/mmu: Rename page-track APIs to reflect the new reality Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 22/27] KVM: x86/mmu: Assert that correct locks are held for page write-tracking Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 23/27] KVM: x86/mmu: Bug the VM if write-tracking is used but not enabled Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 24/27] KVM: x86/mmu: Drop @slot param from exported/external page-track APIs Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 25/27] KVM: x86/mmu: Handle KVM bookkeeping in page-track APIs, not callers Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 26/27] KVM: x86/mmu: Add page-track API to query if a gfn is valid Sean Christopherson
2022-12-28  7:57   ` Yan Zhao
2023-01-03 21:19     ` Sean Christopherson
2023-01-05  3:12       ` Yan Zhao
2023-01-05 17:53         ` Sean Christopherson
2022-12-23  0:57 ` [Intel-gfx] [PATCH 27/27] drm/i915/gvt: Drop final dependencies on KVM internal details Sean Christopherson
2022-12-23  1:28 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for drm/i915/gvt: KVM: KVMGT fixes and page-track cleanups Patchwork
2022-12-23  9:05 ` [Intel-gfx] [PATCH 00/27] " Yan Zhao
2023-01-04  1:01   ` Sean Christopherson
2023-01-05  3:13     ` Yan Zhao
2022-12-28  5:28 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for drm/i915/gvt: KVM: KVMGT fixes and page-track cleanups (rev2) Patchwork
2023-01-06  6:25 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for drm/i915/gvt: KVM: KVMGT fixes and page-track cleanups (rev3) Patchwork
2023-01-19  9:01 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for drm/i915/gvt: KVM: KVMGT fixes and page-track cleanups (rev4) Patchwork

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