diff mbox series

[1/8] KVM: x86: Add initializer for gfn_to_pfn_cache

Message ID 20220921020140.3240092-2-mhal@rbox.co (mailing list archive)
State New, archived
Headers show
Series KVM: x86: gfn_to_pfn_cache cleanups and a fix | expand

Commit Message

Michal Luczaj Sept. 21, 2022, 2:01 a.m. UTC 
Move the gfn_to_pfn_cache lock initialization to another helper and
call the new helper during VM/vCPU creation.

Rename "cache_init" and "cache_destroy" to activate+deactivate to
avoid implying that the cache really is destroyed/freed.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
---
 arch/x86/kvm/x86.c       | 12 +++++----
 arch/x86/kvm/xen.c       | 57 +++++++++++++++++++++-------------------
 include/linux/kvm_host.h | 23 +++++++++++-----
 virt/kvm/pfncache.c      | 21 ++++++++-------
 4 files changed, 65 insertions(+), 48 deletions(-)

Comments

Sean Christopherson Oct. 10, 2022, 11:38 p.m. UTC | #1 
On Wed, Sep 21, 2022, Michal Luczaj wrote:
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index f4519d3689e1..9fd67026d91a 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -1241,8 +1241,17 @@ int kvm_vcpu_write_guest(struct kvm_vcpu *vcpu, gpa_t gpa, const void *data,
>  void kvm_vcpu_mark_page_dirty(struct kvm_vcpu *vcpu, gfn_t gfn);
>  
>  /**
> - * kvm_gfn_to_pfn_cache_init - prepare a cached kernel mapping and HPA for a
> - *                             given guest physical address.
> + * kvm_gpc_init - initialize gfn_to_pfn_cache.
> + *
> + * @gpc:	   struct gfn_to_pfn_cache object.
> + *
> + * This sets up a gfn_to_pfn_cache by initializing locks.

I think it makes sense to add a blurb calling out that the cache needs to be
zeroed before init, i.e. needs to be zero-allocated.  I'll add it in v2.
diff mbox series

Patch

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 43a6a7efc6ec..15032b7f0589 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2301,11 +2301,11 @@  static void kvm_write_system_time(struct kvm_vcpu *vcpu, gpa_t system_time,
 
 	/* we verify if the enable bit is set... */
 	if (system_time & 1) {
-		kvm_gfn_to_pfn_cache_init(vcpu->kvm, &vcpu->arch.pv_time, vcpu,
-					  KVM_HOST_USES_PFN, system_time & ~1ULL,
-					  sizeof(struct pvclock_vcpu_time_info));
+		kvm_gpc_activate(vcpu->kvm, &vcpu->arch.pv_time, vcpu,
+				 KVM_HOST_USES_PFN, system_time & ~1ULL,
+				 sizeof(struct pvclock_vcpu_time_info));
 	} else {
-		kvm_gfn_to_pfn_cache_destroy(vcpu->kvm, &vcpu->arch.pv_time);
+		kvm_gpc_deactivate(vcpu->kvm, &vcpu->arch.pv_time);
 	}
 
 	return;
@@ -3374,7 +3374,7 @@  static int kvm_pv_enable_async_pf_int(struct kvm_vcpu *vcpu, u64 data)
 
 static void kvmclock_reset(struct kvm_vcpu *vcpu)
 {
-	kvm_gfn_to_pfn_cache_destroy(vcpu->kvm, &vcpu->arch.pv_time);
+	kvm_gpc_deactivate(vcpu->kvm, &vcpu->arch.pv_time);
 	vcpu->arch.time = 0;
 }
 
@@ -11551,6 +11551,8 @@  int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 	vcpu->arch.regs_avail = ~0;
 	vcpu->arch.regs_dirty = ~0;
 
+	kvm_gpc_init(&vcpu->arch.pv_time);
+
 	if (!irqchip_in_kernel(vcpu->kvm) || kvm_vcpu_is_reset_bsp(vcpu))
 		vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
 	else
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index 280cb5dc7341..cecf8299b187 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -42,13 +42,13 @@  static int kvm_xen_shared_info_init(struct kvm *kvm, gfn_t gfn)
 	int idx = srcu_read_lock(&kvm->srcu);
 
 	if (gfn == GPA_INVALID) {
-		kvm_gfn_to_pfn_cache_destroy(kvm, gpc);
+		kvm_gpc_deactivate(kvm, gpc);
 		goto out;
 	}
 
 	do {
-		ret = kvm_gfn_to_pfn_cache_init(kvm, gpc, NULL, KVM_HOST_USES_PFN,
-						gpa, PAGE_SIZE);
+		ret = kvm_gpc_activate(kvm, gpc, NULL, KVM_HOST_USES_PFN, gpa,
+				       PAGE_SIZE);
 		if (ret)
 			goto out;
 
@@ -554,15 +554,15 @@  int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
 			     offsetof(struct compat_vcpu_info, time));
 
 		if (data->u.gpa == GPA_INVALID) {
-			kvm_gfn_to_pfn_cache_destroy(vcpu->kvm, &vcpu->arch.xen.vcpu_info_cache);
+			kvm_gpc_deactivate(vcpu->kvm, &vcpu->arch.xen.vcpu_info_cache);
 			r = 0;
 			break;
 		}
 
-		r = kvm_gfn_to_pfn_cache_init(vcpu->kvm,
-					      &vcpu->arch.xen.vcpu_info_cache,
-					      NULL, KVM_HOST_USES_PFN, data->u.gpa,
-					      sizeof(struct vcpu_info));
+		r = kvm_gpc_activate(vcpu->kvm,
+				     &vcpu->arch.xen.vcpu_info_cache, NULL,
+				     KVM_HOST_USES_PFN, data->u.gpa,
+				     sizeof(struct vcpu_info));
 		if (!r)
 			kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
 
@@ -570,16 +570,16 @@  int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
 
 	case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
 		if (data->u.gpa == GPA_INVALID) {
-			kvm_gfn_to_pfn_cache_destroy(vcpu->kvm,
-						     &vcpu->arch.xen.vcpu_time_info_cache);
+			kvm_gpc_deactivate(vcpu->kvm,
+					   &vcpu->arch.xen.vcpu_time_info_cache);
 			r = 0;
 			break;
 		}
 
-		r = kvm_gfn_to_pfn_cache_init(vcpu->kvm,
-					      &vcpu->arch.xen.vcpu_time_info_cache,
-					      NULL, KVM_HOST_USES_PFN, data->u.gpa,
-					      sizeof(struct pvclock_vcpu_time_info));
+		r = kvm_gpc_activate(vcpu->kvm,
+				     &vcpu->arch.xen.vcpu_time_info_cache,
+				     NULL, KVM_HOST_USES_PFN, data->u.gpa,
+				     sizeof(struct pvclock_vcpu_time_info));
 		if (!r)
 			kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
 		break;
@@ -590,16 +590,15 @@  int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
 			break;
 		}
 		if (data->u.gpa == GPA_INVALID) {
-			kvm_gfn_to_pfn_cache_destroy(vcpu->kvm,
-						     &vcpu->arch.xen.runstate_cache);
+			kvm_gpc_deactivate(vcpu->kvm,
+					   &vcpu->arch.xen.runstate_cache);
 			r = 0;
 			break;
 		}
 
-		r = kvm_gfn_to_pfn_cache_init(vcpu->kvm,
-					      &vcpu->arch.xen.runstate_cache,
-					      NULL, KVM_HOST_USES_PFN, data->u.gpa,
-					      sizeof(struct vcpu_runstate_info));
+		r = kvm_gpc_activate(vcpu->kvm, &vcpu->arch.xen.runstate_cache,
+				     NULL, KVM_HOST_USES_PFN, data->u.gpa,
+				     sizeof(struct vcpu_runstate_info));
 		break;
 
 	case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT:
@@ -1817,7 +1816,12 @@  void kvm_xen_init_vcpu(struct kvm_vcpu *vcpu)
 {
 	vcpu->arch.xen.vcpu_id = vcpu->vcpu_idx;
 	vcpu->arch.xen.poll_evtchn = 0;
+
 	timer_setup(&vcpu->arch.xen.poll_timer, cancel_evtchn_poll, 0);
+
+	kvm_gpc_init(&vcpu->arch.xen.runstate_cache);
+	kvm_gpc_init(&vcpu->arch.xen.vcpu_info_cache);
+	kvm_gpc_init(&vcpu->arch.xen.vcpu_time_info_cache);
 }
 
 void kvm_xen_destroy_vcpu(struct kvm_vcpu *vcpu)
@@ -1825,18 +1829,17 @@  void kvm_xen_destroy_vcpu(struct kvm_vcpu *vcpu)
 	if (kvm_xen_timer_enabled(vcpu))
 		kvm_xen_stop_timer(vcpu);
 
-	kvm_gfn_to_pfn_cache_destroy(vcpu->kvm,
-				     &vcpu->arch.xen.runstate_cache);
-	kvm_gfn_to_pfn_cache_destroy(vcpu->kvm,
-				     &vcpu->arch.xen.vcpu_info_cache);
-	kvm_gfn_to_pfn_cache_destroy(vcpu->kvm,
-				     &vcpu->arch.xen.vcpu_time_info_cache);
+	kvm_gpc_deactivate(vcpu->kvm, &vcpu->arch.xen.runstate_cache);
+	kvm_gpc_deactivate(vcpu->kvm, &vcpu->arch.xen.vcpu_info_cache);
+	kvm_gpc_deactivate(vcpu->kvm, &vcpu->arch.xen.vcpu_time_info_cache);
+
 	del_timer_sync(&vcpu->arch.xen.poll_timer);
 }
 
 void kvm_xen_init_vm(struct kvm *kvm)
 {
 	idr_init(&kvm->arch.xen.evtchn_ports);
+	kvm_gpc_init(&kvm->arch.xen.shinfo_cache);
 }
 
 void kvm_xen_destroy_vm(struct kvm *kvm)
@@ -1844,7 +1847,7 @@  void kvm_xen_destroy_vm(struct kvm *kvm)
 	struct evtchnfd *evtchnfd;
 	int i;
 
-	kvm_gfn_to_pfn_cache_destroy(kvm, &kvm->arch.xen.shinfo_cache);
+	kvm_gpc_deactivate(kvm, &kvm->arch.xen.shinfo_cache);
 
 	idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i) {
 		if (!evtchnfd->deliver.port.port)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index f4519d3689e1..9fd67026d91a 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1241,8 +1241,17 @@  int kvm_vcpu_write_guest(struct kvm_vcpu *vcpu, gpa_t gpa, const void *data,
 void kvm_vcpu_mark_page_dirty(struct kvm_vcpu *vcpu, gfn_t gfn);
 
 /**
- * kvm_gfn_to_pfn_cache_init - prepare a cached kernel mapping and HPA for a
- *                             given guest physical address.
+ * kvm_gpc_init - initialize gfn_to_pfn_cache.
+ *
+ * @gpc:	   struct gfn_to_pfn_cache object.
+ *
+ * This sets up a gfn_to_pfn_cache by initializing locks.
+ */
+void kvm_gpc_init(struct gfn_to_pfn_cache *gpc);
+
+/**
+ * kvm_gpc_activate - prepare a cached kernel mapping and HPA for a given guest
+ *                    physical address.
  *
  * @kvm:	   pointer to kvm instance.
  * @gpc:	   struct gfn_to_pfn_cache object.
@@ -1266,9 +1275,9 @@  void kvm_vcpu_mark_page_dirty(struct kvm_vcpu *vcpu, gfn_t gfn);
  * kvm_gfn_to_pfn_cache_check() to ensure that the cache is valid before
  * accessing the target page.
  */
-int kvm_gfn_to_pfn_cache_init(struct kvm *kvm, struct gfn_to_pfn_cache *gpc,
-			      struct kvm_vcpu *vcpu, enum pfn_cache_usage usage,
-			      gpa_t gpa, unsigned long len);
+int kvm_gpc_activate(struct kvm *kvm, struct gfn_to_pfn_cache *gpc,
+		     struct kvm_vcpu *vcpu, enum pfn_cache_usage usage,
+		     gpa_t gpa, unsigned long len);
 
 /**
  * kvm_gfn_to_pfn_cache_check - check validity of a gfn_to_pfn_cache.
@@ -1325,7 +1334,7 @@  int kvm_gfn_to_pfn_cache_refresh(struct kvm *kvm, struct gfn_to_pfn_cache *gpc,
 void kvm_gfn_to_pfn_cache_unmap(struct kvm *kvm, struct gfn_to_pfn_cache *gpc);
 
 /**
- * kvm_gfn_to_pfn_cache_destroy - destroy and unlink a gfn_to_pfn_cache.
+ * kvm_gpc_deactivate - deactivate and unlink a gfn_to_pfn_cache.
  *
  * @kvm:	   pointer to kvm instance.
  * @gpc:	   struct gfn_to_pfn_cache object.
@@ -1333,7 +1342,7 @@  void kvm_gfn_to_pfn_cache_unmap(struct kvm *kvm, struct gfn_to_pfn_cache *gpc);
  * This removes a cache from the @kvm's list to be processed on MMU notifier
  * invocation.
  */
-void kvm_gfn_to_pfn_cache_destroy(struct kvm *kvm, struct gfn_to_pfn_cache *gpc);
+void kvm_gpc_deactivate(struct kvm *kvm, struct gfn_to_pfn_cache *gpc);
 
 void kvm_sigset_activate(struct kvm_vcpu *vcpu);
 void kvm_sigset_deactivate(struct kvm_vcpu *vcpu);
diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c
index 68ff41d39545..08f97cf97264 100644
--- a/virt/kvm/pfncache.c
+++ b/virt/kvm/pfncache.c
@@ -346,17 +346,20 @@  void kvm_gfn_to_pfn_cache_unmap(struct kvm *kvm, struct gfn_to_pfn_cache *gpc)
 }
 EXPORT_SYMBOL_GPL(kvm_gfn_to_pfn_cache_unmap);
 
+void kvm_gpc_init(struct gfn_to_pfn_cache *gpc)
+{
+	rwlock_init(&gpc->lock);
+	mutex_init(&gpc->refresh_lock);
+}
+EXPORT_SYMBOL_GPL(kvm_gpc_init);
 
-int kvm_gfn_to_pfn_cache_init(struct kvm *kvm, struct gfn_to_pfn_cache *gpc,
-			      struct kvm_vcpu *vcpu, enum pfn_cache_usage usage,
-			      gpa_t gpa, unsigned long len)
+int kvm_gpc_activate(struct kvm *kvm, struct gfn_to_pfn_cache *gpc,
+		     struct kvm_vcpu *vcpu, enum pfn_cache_usage usage,
+		     gpa_t gpa, unsigned long len)
 {
 	WARN_ON_ONCE(!usage || (usage & KVM_GUEST_AND_HOST_USE_PFN) != usage);
 
 	if (!gpc->active) {
-		rwlock_init(&gpc->lock);
-		mutex_init(&gpc->refresh_lock);
-
 		gpc->khva = NULL;
 		gpc->pfn = KVM_PFN_ERR_FAULT;
 		gpc->uhva = KVM_HVA_ERR_BAD;
@@ -371,9 +374,9 @@  int kvm_gfn_to_pfn_cache_init(struct kvm *kvm, struct gfn_to_pfn_cache *gpc,
 	}
 	return kvm_gfn_to_pfn_cache_refresh(kvm, gpc, gpa, len);
 }
-EXPORT_SYMBOL_GPL(kvm_gfn_to_pfn_cache_init);
+EXPORT_SYMBOL_GPL(kvm_gpc_activate);
 
-void kvm_gfn_to_pfn_cache_destroy(struct kvm *kvm, struct gfn_to_pfn_cache *gpc)
+void kvm_gpc_deactivate(struct kvm *kvm, struct gfn_to_pfn_cache *gpc)
 {
 	if (gpc->active) {
 		spin_lock(&kvm->gpc_lock);
@@ -384,4 +387,4 @@  void kvm_gfn_to_pfn_cache_destroy(struct kvm *kvm, struct gfn_to_pfn_cache *gpc)
 		gpc->active = false;
 	}
 }
-EXPORT_SYMBOL_GPL(kvm_gfn_to_pfn_cache_destroy);
+EXPORT_SYMBOL_GPL(kvm_gpc_deactivate);