[PATCH 54/60] kvm: x86: Restrict KVM planes support to KVM_IRQCHIP_SPLIT

["Jörg Rödel" <joro@8bytes.org>]

From: Joerg Roedel <joerg.roedel@amd.com>

The code right now only supports plane-aware IOAPIC IRQ routing for
IRQ-chip in split mode. Enforce that restriction in the KVM x86 code.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/kvm/x86.c       | 8 ++++++--
 include/linux/kvm_host.h | 1 +
 virt/kvm/kvm_main.c      | 5 +++++
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c6910356b061..0b9fa1059481 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -490,6 +490,10 @@ EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_x86_default_max_planes);
 
 unsigned kvm_arch_max_planes(struct kvm *kvm)
 {
+	/* For now, planes are only supported with irqchip=split */
+	if (!irqchip_split(kvm))
+		return 1;
+
 	return kvm_x86_call(max_planes)(kvm);
 }
 
@@ -6833,7 +6837,7 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
 		if (cap->args[0] > KVM_MAX_IRQ_ROUTES)
 			goto split_irqchip_unlock;
 		r = -EEXIST;
-		if (irqchip_in_kernel(kvm))
+		if (irqchip_in_kernel(kvm) || kvm->has_planes)
 			goto split_irqchip_unlock;
 		if (kvm->created_vcpus)
 			goto split_irqchip_unlock;
@@ -7398,7 +7402,7 @@ int kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
 			goto create_irqchip_unlock;
 
 		r = -EINVAL;
-		if (kvm->created_vcpus)
+		if (kvm->created_vcpus || kvm->has_planes)
 			goto create_irqchip_unlock;
 
 		r = kvm_pic_init(kvm);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 3b62fb354267..dbf81e2520f2 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -918,6 +918,7 @@ struct kvm {
 	struct list_head gpc_list;
 
 	struct kvm_plane *planes[KVM_MAX_PLANES];
+	bool has_planes;
 
 	/*
 	 * created_vcpus is protected by kvm->lock, and is incremented
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 8f1a16af519a..ff27cdbe8d92 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -5477,6 +5477,10 @@ static int kvm_vm_ioctl_create_plane(struct kvm *kvm, unsigned id)
 	    WARN_ON_ONCE(id >= KVM_MAX_PLANES))
 		return -EINVAL;
 
+	/* Planes are only supported with in-kernel IRQ-chip */
+	if (!kvm_arch_irqchip_in_kernel(kvm))
+		return -EINVAL;
+
 	guard(mutex)(&kvm->lock);
 	if (kvm->planes[id])
 		return -EEXIST;
@@ -5498,6 +5502,7 @@ static int kvm_vm_ioctl_create_plane(struct kvm *kvm, unsigned id)
 		goto put_kvm;
 	}
 
+	kvm->has_planes = true;
 	fd_install(fd, file);
 	return fd;
 
-- 
2.53.0