kvm/x86: split ioapic-handled and EOI exit bitmaps

The function to determine if the vector is handled by ioapic used to
rely on the fact that only ioapic-handled vectors were set up to
cause vmexits when virtual apic was in use.

We're going to break this assumption when introducing Hyper-V
synthetic interrupts: they may need to cause vmexits too.

To achieve that, introduce a new bitmap dedicated specifically for
ioapic-handled vectors, and populate EOI exit bitmap from it for now.

Signed-off-by: Andrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Gleb Natapov <gleb@kernel.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Roman Kagan <rkagan@virtuozzo.com>
CC: Denis V. Lunev <den@openvz.org>
CC: qemu-devel@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -400,7 +400,7 @@ struct kvm_vcpu_arch {
 	u64 efer;
 	u64 apic_base;
 	struct kvm_lapic *apic;    /* kernel irqchip context */
-	u64 eoi_exit_bitmap[4];
+	DECLARE_BITMAP(ioapic_handled_vectors, 256);
 	unsigned long apic_attention;
 	int32_t apic_arb_prio;
 	int mp_state;
@@ -834,7 +834,7 @@ struct kvm_x86_ops {
 	int (*cpu_uses_apicv)(struct kvm_vcpu *vcpu);
 	void (*hwapic_irr_update)(struct kvm_vcpu *vcpu, int max_irr);
 	void (*hwapic_isr_update)(struct kvm *kvm, int isr);
-	void (*load_eoi_exitmap)(struct kvm_vcpu *vcpu);
+	void (*load_eoi_exitmap)(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap);
 	void (*set_virtual_x2apic_mode)(struct kvm_vcpu *vcpu, bool set);
 	void (*set_apic_access_page_addr)(struct kvm_vcpu *vcpu, hpa_t hpa);
 	void (*deliver_posted_interrupt)(struct kvm_vcpu *vcpu, int vector);

arch/x86/kvm/ioapic.c

@@ -233,7 +233,7 @@ static void kvm_ioapic_inject_all(struct kvm_ioapic *ioapic, unsigned long irr)
 }
 
 
-void kvm_ioapic_scan_entry(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)
+void kvm_ioapic_scan_entry(struct kvm_vcpu *vcpu, ulong *ioapic_handled_vectors)
 {
 	struct kvm_ioapic *ioapic = vcpu->kvm->arch.vioapic;
 	union kvm_ioapic_redirect_entry *e;
@@ -250,7 +250,7 @@ void kvm_ioapic_scan_entry(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)
 			    (e->fields.trig_mode == IOAPIC_EDGE_TRIG &&
 			     kvm_apic_pending_eoi(vcpu, e->fields.vector)))
 				__set_bit(e->fields.vector,
-					(unsigned long *)eoi_exit_bitmap);
+					  ioapic_handled_vectors);
 		}
 	}
 	spin_unlock(&ioapic->lock);

arch/x86/kvm/ioapic.h

@@ -121,7 +121,8 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
 		struct kvm_lapic_irq *irq, unsigned long *dest_map);
 int kvm_get_ioapic(struct kvm *kvm, struct kvm_ioapic_state *state);
 int kvm_set_ioapic(struct kvm *kvm, struct kvm_ioapic_state *state);
-void kvm_ioapic_scan_entry(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap);
-void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap);
-
+void kvm_ioapic_scan_entry(struct kvm_vcpu *vcpu,
+			   ulong *ioapic_handled_vectors);
+void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu,
+			    ulong *ioapic_handled_vectors);
 #endif

arch/x86/kvm/irq_comm.c

@@ -339,7 +339,8 @@ void kvm_arch_post_irq_routing_update(struct kvm *kvm)
 	kvm_make_scan_ioapic_request(kvm);
 }
 
-void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)
+void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu,
+			    ulong *ioapic_handled_vectors)
 {
 	struct kvm *kvm = vcpu->kvm;
 	struct kvm_kernel_irq_routing_entry *entry;
@@ -369,7 +370,7 @@ void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)
 				u32 vector = entry->msi.data & 0xff;
 
 				__set_bit(vector,
-					  (unsigned long *) eoi_exit_bitmap);
+					  ioapic_handled_vectors);
 			}
 		}
 	}

arch/x86/kvm/lapic.c

@@ -932,7 +932,7 @@ int kvm_apic_compare_prio(struct kvm_vcpu *vcpu1, struct kvm_vcpu *vcpu2)
 
 static bool kvm_ioapic_handles_vector(struct kvm_lapic *apic, int vector)
 {
-	return test_bit(vector, (ulong *)apic->vcpu->arch.eoi_exit_bitmap);
+	return test_bit(vector, apic->vcpu->arch.ioapic_handled_vectors);
 }
 
 static void kvm_ioapic_send_eoi(struct kvm_lapic *apic, int vector)

arch/x86/kvm/svm.c

@@ -3564,7 +3564,7 @@ static int svm_cpu_uses_apicv(struct kvm_vcpu *vcpu)
 	return 0;
 }
 
-static void svm_load_eoi_exitmap(struct kvm_vcpu *vcpu)
+static void svm_load_eoi_exitmap(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)
 {
 	return;
 }

arch/x86/kvm/vmx.c

@@ -8257,9 +8257,8 @@ static void vmx_hwapic_irr_update(struct kvm_vcpu *vcpu, int max_irr)
 	}
 }
 
-static void vmx_load_eoi_exitmap(struct kvm_vcpu *vcpu)
+static void vmx_load_eoi_exitmap(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)
 {
-	u64 *eoi_exit_bitmap = vcpu->arch.eoi_exit_bitmap;
 	if (!vmx_cpu_uses_apicv(vcpu))
 		return;
 

arch/x86/kvm/x86.c

@@ -6301,15 +6301,16 @@ static void vcpu_scan_ioapic(struct kvm_vcpu *vcpu)
 	if (!kvm_apic_hw_enabled(vcpu->arch.apic))
 		return;
 
-	memset(vcpu->arch.eoi_exit_bitmap, 0, 256 / 8);
+	bitmap_zero(vcpu->arch.ioapic_handled_vectors, 256);
 
 	if (irqchip_split(vcpu->kvm))
-		kvm_scan_ioapic_routes(vcpu, vcpu->arch.eoi_exit_bitmap);
+		kvm_scan_ioapic_routes(vcpu, vcpu->arch.ioapic_handled_vectors);
 	else {
 		kvm_x86_ops->sync_pir_to_irr(vcpu);
-		kvm_ioapic_scan_entry(vcpu, vcpu->arch.eoi_exit_bitmap);
+		kvm_ioapic_scan_entry(vcpu, vcpu->arch.ioapic_handled_vectors);
 	}
-	kvm_x86_ops->load_eoi_exitmap(vcpu);
+	kvm_x86_ops->load_eoi_exitmap(vcpu,
+				      (u64 *)vcpu->arch.ioapic_handled_vectors);
 }
 
 static void kvm_vcpu_flush_tlb(struct kvm_vcpu *vcpu)
@@ -6417,7 +6418,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 		if (kvm_check_request(KVM_REQ_IOAPIC_EOI_EXIT, vcpu)) {
 			BUG_ON(vcpu->arch.pending_ioapic_eoi > 255);
 			if (test_bit(vcpu->arch.pending_ioapic_eoi,
-				     (void *) vcpu->arch.eoi_exit_bitmap)) {
+				     vcpu->arch.ioapic_handled_vectors)) {
 				vcpu->run->exit_reason = KVM_EXIT_IOAPIC_EOI;
 				vcpu->run->eoi.vector =
 						vcpu->arch.pending_ioapic_eoi;