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From:   Dmytro Maluka <dmy@semihalf.com>
To:     Sean Christopherson <seanjc@google.com>,
        Paolo Bonzini <pbonzini@redhat.com>, kvm@vger.kernel.org
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>, linux-kernel@vger.kernel.org,
        Eric Auger <eric.auger@redhat.com>,
        Alex Williamson <alex.williamson@redhat.com>,
        Rong L Liu <rong.l.liu@intel.com>,
        Zhenyu Wang <zhenyuw@linux.intel.com>,
        Tomasz Nowicki <tn@semihalf.com>,
        Grzegorz Jaszczyk <jaz@semihalf.com>, upstream@semihalf.com,
        Dmitry Torokhov <dtor@google.com>,
        Dmytro Maluka <dmy@semihalf.com>
Subject: [PATCH v2 1/5] KVM: x86: Move irq mask notifiers from x86 to generic KVM
Date:   Fri,  5 Aug 2022 21:39:15 +0200
Message-Id: <20220805193919.1470653-2-dmy@semihalf.com>
In-Reply-To: <20220805193919.1470653-1-dmy@semihalf.com>
References: <20220805193919.1470653-1-dmy@semihalf.com>
MIME-Version: 1.0
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Currently irq mask notifiers are used only internally in the x86 code
for PIT emulation. However they are not really arch specific. We are
going to use them in the generic irqfd code, for postponing resampler
irqfd notification until the interrupt is unmasked. So move the
implementation of mask notifiers to the generic code, to allow irqfd to
register its mask notifiers.

Note that calling mask notifiers via calling kvm_fire_mask_notifiers()
is still implemented for x86 only, so registering mask notifiers on
other architectures will have no effect for now.

Signed-off-by: Dmytro Maluka <dmy@semihalf.com>
---
 arch/x86/include/asm/kvm_host.h | 16 ----------------
 arch/x86/kvm/irq_comm.c         | 33 ---------------------------------
 arch/x86/kvm/x86.c              |  1 -
 include/linux/kvm_host.h        | 15 +++++++++++++++
 virt/kvm/eventfd.c              | 33 +++++++++++++++++++++++++++++++++
 virt/kvm/kvm_main.c             |  1 +
 6 files changed, 49 insertions(+), 50 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 9217bd6cf0d1..dc76617f11c1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1198,9 +1198,6 @@ struct kvm_arch {
 
 	struct kvm_xen_hvm_config xen_hvm_config;
 
-	/* reads protected by irq_srcu, writes by irq_lock */
-	struct hlist_head mask_notifier_list;
-
 	struct kvm_hv hyperv;
 	struct kvm_xen xen;
 
@@ -1688,19 +1685,6 @@ int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3);
 int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
 			  const void *val, int bytes);
 
-struct kvm_irq_mask_notifier {
-	void (*func)(struct kvm_irq_mask_notifier *kimn, bool masked);
-	int irq;
-	struct hlist_node link;
-};
-
-void kvm_register_irq_mask_notifier(struct kvm *kvm, int irq,
-				    struct kvm_irq_mask_notifier *kimn);
-void kvm_unregister_irq_mask_notifier(struct kvm *kvm, int irq,
-				      struct kvm_irq_mask_notifier *kimn);
-void kvm_fire_mask_notifiers(struct kvm *kvm, unsigned irqchip, unsigned pin,
-			     bool mask);
-
 extern bool tdp_enabled;
 
 u64 vcpu_tsc_khz(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
index 0687162c4f22..f27e4c9c403e 100644
--- a/arch/x86/kvm/irq_comm.c
+++ b/arch/x86/kvm/irq_comm.c
@@ -234,39 +234,6 @@ void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id)
 	mutex_unlock(&kvm->irq_lock);
 }
 
-void kvm_register_irq_mask_notifier(struct kvm *kvm, int irq,
-				    struct kvm_irq_mask_notifier *kimn)
-{
-	mutex_lock(&kvm->irq_lock);
-	kimn->irq = irq;
-	hlist_add_head_rcu(&kimn->link, &kvm->arch.mask_notifier_list);
-	mutex_unlock(&kvm->irq_lock);
-}
-
-void kvm_unregister_irq_mask_notifier(struct kvm *kvm, int irq,
-				      struct kvm_irq_mask_notifier *kimn)
-{
-	mutex_lock(&kvm->irq_lock);
-	hlist_del_rcu(&kimn->link);
-	mutex_unlock(&kvm->irq_lock);
-	synchronize_srcu(&kvm->irq_srcu);
-}
-
-void kvm_fire_mask_notifiers(struct kvm *kvm, unsigned irqchip, unsigned pin,
-			     bool mask)
-{
-	struct kvm_irq_mask_notifier *kimn;
-	int idx, gsi;
-
-	idx = srcu_read_lock(&kvm->irq_srcu);
-	gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin);
-	if (gsi != -1)
-		hlist_for_each_entry_rcu(kimn, &kvm->arch.mask_notifier_list, link)
-			if (kimn->irq == gsi)
-				kimn->func(kimn, mask);
-	srcu_read_unlock(&kvm->irq_srcu, idx);
-}
-
 bool kvm_arch_can_set_irq_routing(struct kvm *kvm)
 {
 	return irqchip_in_kernel(kvm);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e5fa335a4ea7..a0a776f5c42f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11818,7 +11818,6 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 	if (ret)
 		goto out_page_track;
 
-	INIT_HLIST_HEAD(&kvm->arch.mask_notifier_list);
 	INIT_LIST_HEAD(&kvm->arch.assigned_dev_head);
 	atomic_set(&kvm->arch.noncoherent_dma_count, 0);
 
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 90a45ef7203b..dd5f14e31996 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -760,7 +760,10 @@ struct kvm {
 	struct kvm_irq_routing_table __rcu *irq_routing;
 #endif
 #ifdef CONFIG_HAVE_KVM_IRQFD
+	/* reads protected by irq_srcu, writes by irq_lock */
 	struct hlist_head irq_ack_notifier_list;
+	/* reads protected by irq_srcu, writes by irq_lock */
+	struct hlist_head irq_mask_notifier_list;
 #endif
 
 #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
@@ -1581,6 +1584,12 @@ struct kvm_irq_ack_notifier {
 	void (*irq_acked)(struct kvm_irq_ack_notifier *kian);
 };
 
+struct kvm_irq_mask_notifier {
+	void (*func)(struct kvm_irq_mask_notifier *kimn, bool masked);
+	int irq;
+	struct hlist_node link;
+};
+
 int kvm_irq_map_gsi(struct kvm *kvm,
 		    struct kvm_kernel_irq_routing_entry *entries, int gsi);
 int kvm_irq_map_chip_pin(struct kvm *kvm, unsigned irqchip, unsigned pin);
@@ -1599,6 +1608,12 @@ void kvm_register_irq_ack_notifier(struct kvm *kvm,
 				   struct kvm_irq_ack_notifier *kian);
 void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
 				   struct kvm_irq_ack_notifier *kian);
+void kvm_register_irq_mask_notifier(struct kvm *kvm, int irq,
+				    struct kvm_irq_mask_notifier *kimn);
+void kvm_unregister_irq_mask_notifier(struct kvm *kvm, int irq,
+				      struct kvm_irq_mask_notifier *kimn);
+void kvm_fire_mask_notifiers(struct kvm *kvm, unsigned irqchip, unsigned pin,
+			     bool mask);
 int kvm_request_irq_source_id(struct kvm *kvm);
 void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id);
 bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args);
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 2a3ed401ce46..39403d9fbdcc 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -518,6 +518,39 @@ void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
 	synchronize_srcu(&kvm->irq_srcu);
 	kvm_arch_post_irq_ack_notifier_list_update(kvm);
 }
+
+void kvm_register_irq_mask_notifier(struct kvm *kvm, int irq,
+				    struct kvm_irq_mask_notifier *kimn)
+{
+	mutex_lock(&kvm->irq_lock);
+	kimn->irq = irq;
+	hlist_add_head_rcu(&kimn->link, &kvm->irq_mask_notifier_list);
+	mutex_unlock(&kvm->irq_lock);
+}
+
+void kvm_unregister_irq_mask_notifier(struct kvm *kvm, int irq,
+				      struct kvm_irq_mask_notifier *kimn)
+{
+	mutex_lock(&kvm->irq_lock);
+	hlist_del_rcu(&kimn->link);
+	mutex_unlock(&kvm->irq_lock);
+	synchronize_srcu(&kvm->irq_srcu);
+}
+
+void kvm_fire_mask_notifiers(struct kvm *kvm, unsigned irqchip, unsigned pin,
+			     bool mask)
+{
+	struct kvm_irq_mask_notifier *kimn;
+	int idx, gsi;
+
+	idx = srcu_read_lock(&kvm->irq_srcu);
+	gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin);
+	if (gsi != -1)
+		hlist_for_each_entry_rcu(kimn, &kvm->irq_mask_notifier_list, link)
+			if (kimn->irq == gsi)
+				kimn->func(kimn, mask);
+	srcu_read_unlock(&kvm->irq_srcu, idx);
+}
 #endif
 
 void
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index a49df8988cd6..5ca7fb0b8257 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1144,6 +1144,7 @@ static struct kvm *kvm_create_vm(unsigned long type)
 
 #ifdef CONFIG_HAVE_KVM_IRQFD
 	INIT_HLIST_HEAD(&kvm->irq_ack_notifier_list);
+	INIT_HLIST_HEAD(&kvm->irq_mask_notifier_list);
 #endif
 
 	r = kvm_init_mmu_notifier(kvm);
-- 
2.37.1.559.g78731f0fdb-goog