From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marcelo Tosatti <mtosatti@redhat.com>
Subject: [patch 2/3] KVM: x86: disallow KVM_{SET,GET}_LAPIC without allocated in-kernel lapic
Date: Thu, 29 Oct 2009 13:44:16 -0200
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References: <20091029154414.686484229@amt.cnet>
Cc: kvm@vger.kernel.org, mst@redhat.com, gleb@redhat.com,
	Marcelo Tosatti <mtosatti@redhat.com>
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Otherwise kvm might attempt to dereference a NULL pointer.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Index: kvm/arch/x86/kvm/x86.c
===================================================================
--- kvm.orig/arch/x86/kvm/x86.c
+++ kvm/arch/x86/kvm/x86.c
@@ -1893,6 +1893,9 @@ long kvm_arch_vcpu_ioctl(struct file *fi
 
 	switch (ioctl) {
 	case KVM_GET_LAPIC: {
+		r = -EINVAL;
+		if (!vcpu->arch.apic)
+			goto out;
 		lapic = kzalloc(sizeof(struct kvm_lapic_state), GFP_KERNEL);
 
 		r = -ENOMEM;
@@ -1908,6 +1911,9 @@ long kvm_arch_vcpu_ioctl(struct file *fi
 		break;
 	}
 	case KVM_SET_LAPIC: {
+		r = -EINVAL;
+		if (!vcpu->arch.apic)
+			goto out;
 		lapic = kmalloc(sizeof(struct kvm_lapic_state), GFP_KERNEL);
 		r = -ENOMEM;
 		if (!lapic)