[Qemu-devel] [PATCH 1/2] kvm: zero-initialize KVM_SET_GSI_ROUTING input

["Michael S. Tsirkin" <mst@redhat.com>]

kvm_add_routing_entry makes an attempt to
zero-initialize any new routing entry.
However, it fails to initialize padding
within the u field of the structure
kvm_irq_routing_entry.

Other functions like kvm_irqchip_update_msi_route
also fail to initialize the padding field in
kvm_irq_routing_entry.

While mostly harmless, this would prevent us from
reusing these fields for something useful in
the future.

It's better to just make sure all input is initialized.

Once it is, we can also drop complex field by field assignment and just
do the simple *a = *b to update a route entry.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 kvm-all.c | 19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/kvm-all.c b/kvm-all.c
index 405480e..f119ce1 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -1006,11 +1006,8 @@ static void kvm_add_routing_entry(KVMState *s,
     }
     n = s->irq_routes->nr++;
     new = &s->irq_routes->entries[n];
-    memset(new, 0, sizeof(*new));
-    new->gsi = entry->gsi;
-    new->type = entry->type;
-    new->flags = entry->flags;
-    new->u = entry->u;
+
+    *new = *entry;
 
     set_gsi(s, entry->gsi);
 
@@ -1029,9 +1026,7 @@ static int kvm_update_routing_entry(KVMState *s,
             continue;
         }
 
-        entry->type = new_entry->type;
-        entry->flags = new_entry->flags;
-        entry->u = new_entry->u;
+        *entry = *new_entry;
 
         kvm_irqchip_commit_routes(s);
 
@@ -1043,7 +1038,7 @@ static int kvm_update_routing_entry(KVMState *s,
 
 void kvm_irqchip_add_irq_route(KVMState *s, int irq, int irqchip, int pin)
 {
-    struct kvm_irq_routing_entry e;
+    struct kvm_irq_routing_entry e = {};
 
     assert(pin < s->gsi_count);
 
@@ -1156,7 +1151,7 @@ int kvm_irqchip_send_msi(KVMState *s, MSIMessage msg)
             return virq;
         }
 
-        route = g_malloc(sizeof(KVMMSIRoute));
+        route = g_malloc0(sizeof(KVMMSIRoute));
         route->kroute.gsi = virq;
         route->kroute.type = KVM_IRQ_ROUTING_MSI;
         route->kroute.flags = 0;
@@ -1177,7 +1172,7 @@ int kvm_irqchip_send_msi(KVMState *s, MSIMessage msg)
 
 int kvm_irqchip_add_msi_route(KVMState *s, MSIMessage msg)
 {
-    struct kvm_irq_routing_entry kroute;
+    struct kvm_irq_routing_entry kroute = {};
     int virq;
 
     if (!kvm_gsi_routing_enabled()) {
@@ -1203,7 +1198,7 @@ int kvm_irqchip_add_msi_route(KVMState *s, MSIMessage msg)
 
 int kvm_irqchip_update_msi_route(KVMState *s, int virq, MSIMessage msg)
 {
-    struct kvm_irq_routing_entry kroute;
+    struct kvm_irq_routing_entry kroute = {};
 
     if (!kvm_irqchip_in_kernel()) {
         return -ENOSYS;
-- 
MST