KVM: replace direct irq.h inclusion

virt/kvm/irqchip.c is including "irq.h" from the arch-specific KVM source
directory (i.e. not from arch/*/include) for the sole purpose of retrieving
irqchip_in_kernel.

Making the function inline in a header that is already included,
such as asm/kvm_host.h, is not possible because it needs to look at
struct kvm which is defined after asm/kvm_host.h is included.  So add a
kvm_arch_irqchip_in_kernel non-inline function; irqchip_in_kernel() is
only performance critical on arm64 and x86, and the non-inline function
is enough on all other architectures.

irq.h can then be deleted from all architectures except x86.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/arm64/kvm/arm.c

@@ -2130,6 +2130,11 @@ struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr)
 	return NULL;
 }
 
+bool kvm_arch_irqchip_in_kernel(struct kvm *kvm)
+{
+	return irqchip_in_kernel(kvm);
+}
+
 bool kvm_arch_has_irq_bypass(void)
 {
 	return true;

arch/arm64/kvm/irq.h

-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * irq.h: in kernel interrupt controller related definitions
- * Copyright (c) 2016 Red Hat, Inc.
- *
- * This header is included by irqchip.c. However, on ARM, interrupt
- * controller declarations are located in include/kvm/arm_vgic.h since
- * they are mostly shared between arm and arm64.
- */
-
-#ifndef __IRQ_H
-#define __IRQ_H
-
-#include <kvm/arm_vgic.h>
-
-#endif

arch/powerpc/kvm/irq.h

-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __IRQ_H
-#define __IRQ_H
-
-#include <linux/kvm_host.h>
-
-static inline int irqchip_in_kernel(struct kvm *kvm)
-{
-	int ret = 0;
-
-#ifdef CONFIG_KVM_MPIC
-	ret = ret || (kvm->arch.mpic != NULL);
-#endif
-#ifdef CONFIG_KVM_XICS
-	ret = ret || (kvm->arch.xics != NULL);
-	ret = ret || (kvm->arch.xive != NULL);
-#endif
-	smp_rmb();
-	return ret;
-}
-
-#endif

arch/powerpc/kvm/powerpc.c

@@ -36,7 +36,6 @@
 #include <asm/setup.h>
 
 #include "timing.h"
-#include "irq.h"
 #include "../mm/mmu_decl.h"
 
 #define CREATE_TRACE_POINTS
@@ -2165,10 +2164,25 @@ static int kvm_vm_ioctl_get_pvinfo(struct kvm_ppc_pvinfo *pvinfo)
 	return 0;
 }
 
+bool kvm_arch_irqchip_in_kernel(struct kvm *kvm)
+{
+	int ret = 0;
+
+#ifdef CONFIG_KVM_MPIC
+	ret = ret || (kvm->arch.mpic != NULL);
+#endif
+#ifdef CONFIG_KVM_XICS
+	ret = ret || (kvm->arch.xics != NULL);
+	ret = ret || (kvm->arch.xive != NULL);
+#endif
+	smp_rmb();
+	return ret;
+}
+
 int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_event,
 			  bool line_status)
 {
-	if (!irqchip_in_kernel(kvm))
+	if (!kvm_arch_irqchip_in_kernel(kvm))
 		return -ENXIO;
 
 	irq_event->status = kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID,

arch/s390/kvm/irq.h

-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * s390 irqchip routines
- *
- * Copyright IBM Corp. 2014
- *
- *    Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
- */
-#ifndef __KVM_IRQ_H
-#define __KVM_IRQ_H
-
-#include <linux/kvm_host.h>
-
-static inline int irqchip_in_kernel(struct kvm *kvm)
-{
-	return 1;
-}
-
-#endif

arch/s390/kvm/kvm-s390.c

@@ -5567,6 +5567,11 @@ vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
 	return VM_FAULT_SIGBUS;
 }
 
+bool kvm_arch_irqchip_in_kernel(struct kvm *kvm)
+{
+	return true;
+}
+
 /* Section: memory related */
 int kvm_arch_prepare_memory_region(struct kvm *kvm,
 				   const struct kvm_memory_slot *old,

arch/x86/kvm/irq.c

@@ -165,3 +165,8 @@ bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args)
 
 	return resample ? irqchip_kernel(kvm) : irqchip_in_kernel(kvm);
 }
+
+bool kvm_arch_irqchip_in_kernel(struct kvm *kvm)
+{
+	return irqchip_in_kernel(kvm);
+}

include/linux/kvm_host.h

@@ -663,6 +663,8 @@ struct kvm_irq_routing_table {
 	 */
 	struct hlist_head map[];
 };
+
+bool kvm_arch_irqchip_in_kernel(struct kvm *kvm);
 #endif
 
 #ifndef KVM_INTERNAL_MEM_SLOTS

virt/kvm/irqchip.c

@@ -17,7 +17,6 @@
 #include <linux/srcu.h>
 #include <linux/export.h>
 #include <trace/events/kvm.h>
-#include "irq.h"
 
 int kvm_irq_map_gsi(struct kvm *kvm,
 		    struct kvm_kernel_irq_routing_entry *entries, int gsi)
@@ -50,7 +49,7 @@ int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
 {
 	struct kvm_kernel_irq_routing_entry route;
 
-	if (!irqchip_in_kernel(kvm) || (msi->flags & ~KVM_MSI_VALID_DEVID))
+	if (!kvm_arch_irqchip_in_kernel(kvm) || (msi->flags & ~KVM_MSI_VALID_DEVID))
 		return -EINVAL;
 
 	route.msi.address_lo = msi->address_lo;