> On Thu, 22 Jan 2026 14:45:27 +0530 Srujana Challa wrote: > > Increase VIRTIO_NET_RSS_MAX_KEY_SIZE from 40 to 52 bytes to align with > > the kernel's standard RSS key length defined by NETDEV_RSS_KEY_LEN. > > I've been meaning to bump NETDEV_RSS_KEY_LEN to 128 or some such. > Most modern drivers can't use netdev_rss_key_fill() either because core > generates a tiny key. And the devices support hashing over two layers of IPv6 > for tunnels. Instead of hardcoding 52, we can use:
#define VIRTIO_NET_RSS_MAX_KEY_SIZE NETDEV_RSS_KEY_LEN This automatically stays in sync with NETDEV_RSS_KEY_LEN and will adapt when it's increased to 128+. Please confirm. Thanks. > > Willem, WDYT? Is there a reason to keep the core key small? > Or deprecate netdev_rss_key_fill()? > > > The virtio specification requires devices to support at least 40 bytes > > for the RSS key size. However, devices may support larger key sizes up > > to 52 bytes (as reported by the device's rss_max_key_size config > > field). This change allows such devices to work properly. > > Previously, devices reporting rss_max_key_size > 40 would fail with an > > error during initialization. > > > > The driver already handles variable key sizes dynamically through > > vi->rss_key_size, so increasing the maximum limit is safe and > > maintains backward compatibility with devices that support smaller key > > sizes. > > > -#define VIRTIO_NET_RSS_MAX_KEY_SIZE 40 > > +#define VIRTIO_NET_RSS_MAX_KEY_SIZE 52
