[PATCH] KVM: Make loading cr3 more robust

	vcpu->cr3 = cr3;

	spin_lock(&vcpu->kvm->lock);

	/*

	 * Does the new cr3 value map to physical memory? (Note, we

	 * catch an invalid cr3 even in real-mode, because it would

	 * cause trouble later on when we turn on paging anyway.)

	 *

	 * A real CPU would silently accept an invalid cr3 and would

	 * attempt to use it - with largely undefined (and often hard

	 * to debug) behavior on the guest side.

	 */

	if (unlikely(!gfn_to_memslot(vcpu->kvm, cr3 >> PAGE_SHIFT)))

		inject_gp(vcpu);

	else

		vcpu->mmu.new_cr3(vcpu);

	spin_unlock(&vcpu->kvm->lock);

}