vcpu->cr3 = cr3;
spin_lock(&vcpu->kvm->lock);
- vcpu->mmu.new_cr3(vcpu);
+ /*
+ * 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);
}
EXPORT_SYMBOL_GPL(set_cr3);