[PATCH] kvm: check dev parameter when updating msi route

[P J P <ppandit@xxxxxxxxxx>]

From: Prasad J Pandit <pjp@xxxxxxxxxxxxxxxxx>

When updating message signalled interrupt(MSI) route in routine
kvm_irqchip_update_msi_route, device parameter could be null.
Add check to avoid null dereference.

Reported-by: Guoxiang Niu <niuguoxiang@xxxxxxxxxx>
Signed-off-by: Prasad J Pandit <pjp@xxxxxxxxxxxxxxxxx>
---
 accel/kvm/kvm-all.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index f290f487a5..cb7613d282 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -1167,7 +1167,7 @@ int kvm_irqchip_add_msi_route(KVMState *s, int vector, PCIDevice *dev)
     kroute.u.msi.address_lo = (uint32_t)msg.address;
     kroute.u.msi.address_hi = msg.address >> 32;
     kroute.u.msi.data = le32_to_cpu(msg.data);
-    if (pci_available && kvm_msi_devid_required()) {
+    if (pci_available && dev && kvm_msi_devid_required()) {
         kroute.flags = KVM_MSI_VALID_DEVID;
         kroute.u.msi.devid = pci_requester_id(dev);
     }
@@ -1205,7 +1205,7 @@ int kvm_irqchip_update_msi_route(KVMState *s, int virq, MSIMessage msg,
     kroute.u.msi.address_lo = (uint32_t)msg.address;
     kroute.u.msi.address_hi = msg.address >> 32;
     kroute.u.msi.data = le32_to_cpu(msg.data);
-    if (pci_available && kvm_msi_devid_required()) {
+    if (pci_available && dev && kvm_msi_devid_required()) {
         kroute.flags = KVM_MSI_VALID_DEVID;
         kroute.u.msi.devid = pci_requester_id(dev);
     }
-- 
2.14.3