Re: [PATCH net-next v3 04/11] virtio_net: Query and set flow filter caps

[Simon Horman <horms@kernel.org>]

On Tue, Sep 23, 2025 at 09:19:13AM -0500, Daniel Jurgens wrote:
> When probing a virtnet device, attempt to read the flow filter
> capabilities. In order to use the feature the caps must also
> be set. For now setting what was read is sufficient.
> 
> Signed-off-by: Daniel Jurgens <danielj@nvidia.com>
> Reviewed-by: Parav Pandit <parav@nvidia.com>
> Reviewed-by: Shahar Shitrit <shshitrit@nvidia.com>

...

> diff --git a/include/uapi/linux/virtio_net_ff.h b/include/uapi/linux/virtio_net_ff.h
> new file mode 100644
> index 000000000000..a35533bf8377
> --- /dev/null
> +++ b/include/uapi/linux/virtio_net_ff.h
> @@ -0,0 +1,55 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
> + *
> + * Header file for virtio_net flow filters
> + */
> +#ifndef _LINUX_VIRTIO_NET_FF_H
> +#define _LINUX_VIRTIO_NET_FF_H
> +
> +#include <linux/types.h>
> +#include <linux/kernel.h>
> +
> +#define VIRTIO_NET_FF_RESOURCE_CAP 0x800
> +#define VIRTIO_NET_FF_SELECTOR_CAP 0x801
> +#define VIRTIO_NET_FF_ACTION_CAP 0x802
> +
> +struct virtio_net_ff_cap_data {
> +	__le32 groups_limit;
> +	__le32 classifiers_limit;
> +	__le32 rules_limit;
> +	__le32 rules_per_group_limit;
> +	__u8 last_rule_priority;
> +	__u8 selectors_per_classifier_limit;
> +};
> +
> +struct virtio_net_ff_selector {
> +	__u8 type;
> +	__u8 flags;
> +	__u8 reserved[2];
> +	__u8 length;
> +	__u8 reserved1[3];
> +	__u8 mask[];
> +};
> +
> +#define VIRTIO_NET_FF_MASK_TYPE_ETH  1
> +#define VIRTIO_NET_FF_MASK_TYPE_IPV4 2
> +#define VIRTIO_NET_FF_MASK_TYPE_IPV6 3
> +#define VIRTIO_NET_FF_MASK_TYPE_TCP  4
> +#define VIRTIO_NET_FF_MASK_TYPE_UDP  5
> +#define VIRTIO_NET_FF_MASK_TYPE_MAX  VIRTIO_NET_FF_MASK_TYPE_UDP
> +
> +struct virtio_net_ff_cap_mask_data {
> +	__u8 count;
> +	__u8 reserved[7];
> +	struct virtio_net_ff_selector selectors[];

Hi Daniel,

Sparse warns that the line above is an array of flexible structures.
I wonder if that can be addressed somehow.

> +};
> +#define VIRTIO_NET_FF_MASK_F_PARTIAL_MASK (1 << 0)
> +
> +#define VIRTIO_NET_FF_ACTION_DROP 1
> +#define VIRTIO_NET_FF_ACTION_RX_VQ 2
> +#define VIRTIO_NET_FF_ACTION_MAX  VIRTIO_NET_FF_ACTION_RX_VQ
> +struct virtio_net_ff_actions {
> +	__u8 count;
> +	__u8 reserved[7];
> +	__u8 actions[];
> +};
> +#endif
> -- 
> 2.45.0
> 
>