diff mbox series

[v3,02/10] KVM: x86/mmu: Move TDP MMU VM init/uninit behind tdp_mmu_enabled

Message ID 20220921173546.2674386-3-dmatlack@google.com (mailing list archive)
State New, archived
Headers show
Series KVM: x86/mmu: Make tdp_mmu read-only and clean up TPD MMU fault handler | expand

Commit Message

David Matlack Sept. 21, 2022, 5:35 p.m. UTC 
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@google.com>
---
 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(-)

Comments

Isaku Yamahata Oct. 3, 2022, 7:01 p.m. UTC | #1 
On Wed, Sep 21, 2022 at 10:35:38AM -0700,
David Matlack <dmatlack@google.com> 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@google.com>
> ---
>  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@intel.com>
diff mbox series

Patch

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