On Mon, Aug 03, 2026 at 05:07:13PM +0300, Shahar Shitrit 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.
>
> This patch adds uapi definitions virtio_net flow filters define in
> version 1.4 of the VirtIO spec.
>
> Signed-off-by: Daniel Jurgens <[email protected]>
> Reviewed-by: Parav Pandit <[email protected]>
> Signed-off-by: Shahar Shitrit <[email protected]>
> ---
> drivers/net/virtio_net.c | 239 +++++++++++++++++++++++++++++
> include/uapi/linux/virtio_net_ff.h | 91 +++++++++++
> 2 files changed, 330 insertions(+)
> create mode 100644 include/uapi/linux/virtio_net_ff.h
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 3e2a5876c6c8..0d1f5a6cfd12 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -27,6 +27,11 @@
> #include <net/netdev_queues.h>
> #include <net/xdp_sock_drv.h>
> #include <net/page_pool/helpers.h>
> +#include <linux/virtio_admin.h>
> +#include <net/ipv6.h>
> +#include <net/ip.h>
> +#include <uapi/linux/virtio_pci.h>
why would virtio net need pci macros?
> +#include <uapi/linux/virtio_net_ff.h>
>
> static int napi_weight = NAPI_POLL_WEIGHT;
> module_param(napi_weight, int, 0444);
> @@ -282,6 +287,14 @@ static const struct virtnet_stat_desc
> virtnet_stats_tx_speed_desc_qstat[] = {
> VIRTNET_STATS_DESC_TX_QSTAT(speed, ratelimit_packets,
> hw_drop_ratelimits),
> };
>
> +struct virtnet_ff {
> + struct virtio_device *vdev;
> + bool ff_supported;
> + struct virtio_net_ff_cap_data *ff_caps;
> + struct virtio_net_ff_cap_mask_data *ff_mask;
> + struct virtio_net_ff_actions *ff_actions;
> +};
> +
> #define VIRTNET_Q_TYPE_RX 0
> #define VIRTNET_Q_TYPE_TX 1
> #define VIRTNET_Q_TYPE_CQ 2
> @@ -474,6 +487,8 @@ struct virtnet_info {
>
> struct virtio_net_rss_config_hdr *rss_hdr;
>
> + struct virtnet_ff ff;
> +
> /* Must be last as it ends in a flexible-array member. */
> TRAILING_OVERLAP(struct virtio_net_rss_config_trailer, rss_trailer,
> hash_key_data,
> u8 rss_hash_key_data[NETDEV_RSS_KEY_LEN];
> @@ -519,6 +534,7 @@ static struct sk_buff *virtnet_skb_append_frag(struct
> receive_queue *rq,
> static void virtnet_xsk_completed(struct send_queue *sq, int num);
> static void free_unused_bufs(struct virtnet_info *vi);
> static void virtnet_del_vqs(struct virtnet_info *vi);
> +static void remove_vq_common(struct virtnet_info *vi);
>
> enum virtnet_xmit_type {
> VIRTNET_XMIT_TYPE_SKB,
> @@ -5710,6 +5726,199 @@ static const struct netdev_stat_ops virtnet_stat_ops
> = {
> .get_base_stats = virtnet_get_base_stats,
> };
>
> +static size_t get_mask_size(u16 type)
> +{
> + switch (type) {
> + case VIRTIO_NET_FF_MASK_TYPE_ETH:
> + return sizeof(struct ethhdr);
> + case VIRTIO_NET_FF_MASK_TYPE_IPV4:
> + return sizeof(struct iphdr);
> + case VIRTIO_NET_FF_MASK_TYPE_IPV6:
> + return sizeof(struct ipv6hdr);
> + case VIRTIO_NET_FF_MASK_TYPE_TCP:
> + return sizeof(struct tcphdr);
> + case VIRTIO_NET_FF_MASK_TYPE_UDP:
> + return sizeof(struct udphdr);
> + }
> +
> + return 0;
> +}
> +
> +static int virtnet_ff_init(struct virtnet_ff *ff, struct virtio_device *vdev)
> +{
> + size_t ff_mask_size = sizeof(struct virtio_net_ff_cap_mask_data) +
> + sizeof(struct virtio_net_ff_selector) *
> + VIRTIO_NET_FF_MASK_TYPE_MAX;
> + struct virtio_admin_cmd_query_cap_id_result *cap_id_list;
> + struct virtio_net_ff_selector *sel;
> + unsigned long sel_types = 0;
> + size_t real_ff_mask_size;
> + int err;
> + int i;
> +
> + if (!vdev->config->admin_cmd_exec)
> + return -EOPNOTSUPP;
> +
> + cap_id_list = kzalloc(sizeof(*cap_id_list), GFP_KERNEL);
> + if (!cap_id_list)
> + return -ENOMEM;
> +
> + err = virtio_admin_cap_id_list_query(vdev, cap_id_list);
> + if (err)
> + goto err_cap_list;
> +
> + if (!(VIRTIO_CAP_IN_LIST(cap_id_list,
> + VIRTIO_NET_FF_RESOURCE_CAP) &&
> + VIRTIO_CAP_IN_LIST(cap_id_list,
> + VIRTIO_NET_FF_SELECTOR_CAP) &&
> + VIRTIO_CAP_IN_LIST(cap_id_list,
> + VIRTIO_NET_FF_ACTION_CAP))) {
> + err = -EOPNOTSUPP;
> + goto err_cap_list;
> + }
> +
> + ff->ff_caps = kzalloc(sizeof(*ff->ff_caps), GFP_KERNEL);
> + if (!ff->ff_caps) {
> + err = -ENOMEM;
> + goto err_cap_list;
> + }
> +
> + err = virtio_admin_cap_get(vdev,
> + VIRTIO_NET_FF_RESOURCE_CAP,
> + ff->ff_caps,
> + sizeof(*ff->ff_caps));
> +
> + if (err)
> + goto err_ff;
> +
> + if (!le32_to_cpu(ff->ff_caps->groups_limit) ||
> + !le32_to_cpu(ff->ff_caps->classifiers_limit) ||
> + !le32_to_cpu(ff->ff_caps->rules_limit) ||
> + !le32_to_cpu(ff->ff_caps->rules_per_group_limit)) {
I am not sure why do we validate these specifically.
Should we then validate selectors_per_classifier_limit too?
> + err = -EINVAL;
> + goto err_ff;
> + }
> +
> + /* VIRTIO_NET_FF_MASK_TYPE start at 1 */
> + for (i = 1; i <= VIRTIO_NET_FF_MASK_TYPE_MAX; i++)
> + ff_mask_size += get_mask_size(i);
> +
> + ff->ff_mask = kzalloc(ff_mask_size, GFP_KERNEL);
> + if (!ff->ff_mask) {
> + err = -ENOMEM;
> + goto err_ff;
> + }
> +
> + err = virtio_admin_cap_get(vdev,
> + VIRTIO_NET_FF_SELECTOR_CAP,
> + ff->ff_mask,
> + ff_mask_size);
> +
> + if (err)
> + goto err_ff_mask;
> +
> + ff->ff_mask->count = min_t(u8, ff->ff_mask->count,
> + VIRTIO_NET_FF_MASK_TYPE_MAX);
> +
> + ff->ff_actions = kzalloc(sizeof(*ff->ff_actions) +
> + VIRTIO_NET_FF_ACTION_MAX,
> + GFP_KERNEL);
> + if (!ff->ff_actions) {
> + err = -ENOMEM;
> + goto err_ff_mask;
> + }
> +
> + err = virtio_admin_cap_get(vdev,
> + VIRTIO_NET_FF_ACTION_CAP,
> + ff->ff_actions,
> + sizeof(*ff->ff_actions) +
> VIRTIO_NET_FF_ACTION_MAX);
> +
> + if (err)
> + goto err_ff_action;
> +
> + ff->ff_actions->count = min_t(u8, ff->ff_actions->count,
> + VIRTIO_NET_FF_ACTION_MAX);
and here, do we validate count != 0?
> + err = virtio_admin_cap_set(vdev,
> + VIRTIO_NET_FF_RESOURCE_CAP,
> + ff->ff_caps,
> + sizeof(*ff->ff_caps));
> + if (err)
> + goto err_ff_action;
> +
> + real_ff_mask_size = sizeof(struct virtio_net_ff_cap_mask_data);
> + sel = (void *)&ff->ff_mask->selectors;
> +
> + for (i = 0; i < ff->ff_mask->count; i++) {
> + /* If the selector type is unknown it may indicate the spec
> + * has been revised to include new types of selectors
> + */
> + if (!sel->type || sel->type > VIRTIO_NET_FF_MASK_TYPE_MAX)
> + break;
> +
> + if (sel->length != get_mask_size(sel->type) ||
> + test_and_set_bit(sel->type, &sel_types)) {
> + WARN_ON_ONCE(true);
given we gracefully fail, I'm not sure WARN is justified,
since we don't warn in other validation steps.
However
> + err = -EINVAL;
the error here is on the device side, not user side, right?
maybe a distinct error to indicate this.
> + goto err_ff_action;
> + }
> + real_ff_mask_size += sizeof(*sel) + sel->length;
> + if (real_ff_mask_size > ff_mask_size) {
> + WARN_ON_ONCE(true);
> + err = -EINVAL;
> + goto err_ff_action;
> + }
> + sel = (void *)sel + sizeof(*sel) + sel->length;
> + }
> + ff->ff_mask->count = i;
> +
> + err = virtio_admin_cap_set(vdev,
> + VIRTIO_NET_FF_SELECTOR_CAP,
> + ff->ff_mask,
> + real_ff_mask_size);
> + if (err)
> + goto err_ff_action;
> +
> + err = virtio_admin_cap_set(vdev,
> + VIRTIO_NET_FF_ACTION_CAP,
> + ff->ff_actions,
> + sizeof(*ff->ff_actions) +
> VIRTIO_NET_FF_ACTION_MAX);
why not ff->ff_mask->count? this is all we initialized...
> + if (err)
> + goto err_ff_action;
> +
> + ff->vdev = vdev;
> + ff->ff_supported = true;
> +
> + kfree(cap_id_list);
> +
> + return 0;
> +
> +err_ff_action:
> + kfree(ff->ff_actions);
> + ff->ff_actions = NULL;
> +err_ff_mask:
> + kfree(ff->ff_mask);
> + ff->ff_mask = NULL;
> +err_ff:
> + kfree(ff->ff_caps);
> + ff->ff_caps = NULL;
> +err_cap_list:
> + kfree(cap_id_list);
> +
> + return err;
> +}
> +
> +static void virtnet_ff_cleanup(struct virtnet_ff *ff)
> +{
> + if (!ff->ff_supported)
> + return;
> +
> + kfree(ff->ff_actions);
> + kfree(ff->ff_mask);
> + kfree(ff->ff_caps);
> + ff->ff_supported = false;
> +}
> +
> static void virtnet_freeze_down(struct virtio_device *vdev)
> {
> struct virtnet_info *vi = vdev->priv;
> @@ -5728,6 +5937,10 @@ static void virtnet_freeze_down(struct virtio_device
> *vdev)
> netif_tx_lock_bh(vi->dev);
> netif_device_detach(vi->dev);
> netif_tx_unlock_bh(vi->dev);
> +
> + rtnl_lock();
> + virtnet_ff_cleanup(&vi->ff);
> + rtnl_unlock();
> }
>
> static int init_vqs(struct virtnet_info *vi);
> @@ -5757,9 +5970,24 @@ static int virtnet_restore_up(struct virtio_device
> *vdev)
> goto err_destroy_pools;
> }
>
> + /*
> + * Initialize flow filters. Not supported is an acceptable and common
> + * return code
> + */
> + rtnl_lock();
> + err = virtnet_ff_init(&vi->ff, vi->vdev);
> + if (err && err != -EOPNOTSUPP) {
> + rtnl_unlock();
> + virtnet_freeze_down(vi->vdev);
> + remove_vq_common(vi);
> + return err;
> + }
> + rtnl_unlock();
> +
> netif_tx_lock_bh(vi->dev);
> netif_device_attach(vi->dev);
> netif_tx_unlock_bh(vi->dev);
> +
> return 0;
>
> err_destroy_pools:
> @@ -7043,6 +7271,15 @@ static int virtnet_probe(struct virtio_device *vdev)
>
> virtio_device_ready(vdev);
>
> + /* Initialize flow filters. Not supported is an acceptable and common
> + * return code
> + */
> + err = virtnet_ff_init(&vi->ff, vi->vdev);
> + if (err && err != -EOPNOTSUPP) {
> + rtnl_unlock();
> + goto free_unregister_netdev;
> + }
> +
> if (vi->has_rss || vi->has_rss_hash_report) {
> if (!virtnet_commit_rss_command(vi)) {
> dev_warn(&vdev->dev, "RSS disabled because committing
> failed.\n");
> @@ -7125,6 +7362,7 @@ static int virtnet_probe(struct virtio_device *vdev)
>
> free_unregister_netdev:
> unregister_netdev(dev);
> + virtnet_ff_cleanup(&vi->ff);
> free_failover:
> net_failover_destroy(vi->failover);
> free_page_pools:
> @@ -7175,6 +7413,7 @@ static void virtnet_remove(struct virtio_device *vdev)
> virtnet_free_irq_moder(vi);
>
> unregister_netdev(vi->dev);
> + virtnet_ff_cleanup(&vi->ff);
>
> net_failover_destroy(vi->failover);
>
> diff --git a/include/uapi/linux/virtio_net_ff.h
> b/include/uapi/linux/virtio_net_ff.h
> new file mode 100644
> index 000000000000..f9e771a0baff
> --- /dev/null
> +++ b/include/uapi/linux/virtio_net_ff.h
> @@ -0,0 +1,91 @@
> +/* 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/stddef.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 - Flow filter resource capability limits
> + * @groups_limit: maximum number of flow filter groups supported by the
> device
> + * @classifiers_limit: maximum number of classifiers supported by the device
> + * @rules_limit: maximum number of rules supported device-wide across all
> groups
> + * @rules_per_group_limit: maximum number of rules allowed in a single group
> + * @last_rule_priority: priority value associated with the lowest-priority
> rule
> + * @selectors_per_classifier_limit: maximum selectors allowed in one
> classifier
> + */
> +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;
> + /* private: */
> + __u8 reserved[2];
> +};
> +
> +/**
> + * struct virtio_net_ff_selector - Selector mask descriptor
> + * @type: selector type, one of VIRTIO_NET_FF_MASK_TYPE_* constants
> + * @flags: selector flags, see VIRTIO_NET_FF_MASK_F_* constants
> + * @reserved: must be set to 0 by the driver and ignored by the device
> + * @length: size in bytes of @mask
> + * @reserved1: must be set to 0 by the driver and ignored by the device
> + * @mask: variable-length mask payload for @type, length given by @length
> + *
> + * A selector describes a header mask that a classifier can apply. The format
> + * of @mask depends on @type.
> + */
> +struct virtio_net_ff_selector {
> + __u8 type;
> + __u8 flags;
> + __u8 reserved[2];
> + __u8 length;
> + __u8 reserved1[3];
> + __u8 mask[] __counted_by(length);
> +};
> +
> +#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 - Supported selector mask formats
> + * @count: number of entries in @selectors
> + * @reserved: must be set to 0 by the driver and ignored by the device
> + * @selectors: packed array of struct virtio_net_ff_selector.
> + */
> +struct virtio_net_ff_cap_mask_data {
> + __u8 count;
> + __u8 reserved[7];
> + __u8 selectors[];
> +};
> +
> +#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 - Supported flow actions
> + * @count: number of supported actions in @actions
> + * @reserved: must be set to 0 by the driver and ignored by the device
> + * @actions: array of action identifiers (VIRTIO_NET_FF_ACTION_*)
> + */
> +struct virtio_net_ff_actions {
> + __u8 count;
> + __u8 reserved[7];
> + __u8 actions[] __counted_by(count);
> +};
> +#endif
> --
> 2.49.0
