On Tue, Jun 04, 2013 at 02:52:32PM +0300, Michael S. Tsirkin wrote:
> 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.
>
The fact that kernel does not check them for zero value is what will
prevents us from doing so.
> 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@xxxxxxxxxx>
> ---
> 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
--
Gleb.
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