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KVM: Ensure all vcpus are consistent with in-kernel irqchip settings

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If some vcpus are created before KVM_CREATE_IRQCHIP, then
irqchip_in_kernel() and vcpu->arch.apic will be inconsistent, leading
to potential NULL pointer dereferences.

Fix by:
- ensuring that no vcpus are installed when KVM_CREATE_IRQCHIP is called
- ensuring that a vcpu has an apic if it is installed after KVM_CREATE_IRQCHIP

This is somewhat long winded because vcpu->arch.apic is created without
kvm->lock held.

Based on earlier patch by Michael Ellerman.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Avi Kivity 2012-03-05 14:23:29 +02:00
parent 4cee4798a3
commit 3e515705a1
4 changed files with 24 additions and 0 deletions
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4
virt/kvm/kvm_main.c
View file

@ -1651,6 +1651,10 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
goto vcpu_destroy;
mutex_lock(&kvm->lock);
if (!kvm_vcpu_compatible(vcpu)) {
r = -EINVAL;
goto unlock_vcpu_destroy;
}
if (atomic_read(&kvm->online_vcpus) == KVM_MAX_VCPUS) {
r = -EINVAL;
goto unlock_vcpu_destroy;