KVM: Don't assign vcpu->cr3 if it's invalid: check first, set last

sSigned-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 2be6b1ca1a06..5dc601702782 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -579,7 +579,6 @@ void set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
                 }
         }
 
-        vcpu->cr3 = cr3;
         mutex_lock(&vcpu->kvm->lock);
         /*
          * Does the new cr3 value map to physical memory? (Note, we
@@ -592,8 +591,10 @@ void set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
          */
         if (unlikely(!gfn_to_memslot(vcpu->kvm, cr3 >> PAGE_SHIFT)))
                 inject_gp(vcpu);
-        else
+        else {
+                vcpu->cr3 = cr3;
                 vcpu->mmu.new_cr3(vcpu);
+        }
         mutex_unlock(&vcpu->kvm->lock);
 }
 EXPORT_SYMBOL_GPL(set_cr3);