This patch introduces vhost_vdpa_net_load_rss() to restore the hash calculation state at device's startup.
Signed-off-by: Hawkins Jiawei <yin31...@gmail.com> --- v4: - fix some typos pointed out by Michael - zero the `cfg` fields at the definition suggested by Michael v3: https://patchwork.kernel.org/project/qemu-devel/patch/b7cd0c8d6a58b16b086f11714d2908ad35c67caa.1697902949.git.yin31...@gmail.com/ - remove the `do_rss` argument in vhost_vdpa_net_load_rss() - zero reserved fields in "cfg" manually instead of using memset() to prevent compiler "array-bounds" warning v2: https://lore.kernel.org/all/f5ffad10699001107022851e0560cb394039d6b0.1693297766.git.yin31...@gmail.com/ - resolve conflict with updated patch "vdpa: Send all CVQ state load commands in parallel" - move the `table` declaration at the beginning of the vhost_vdpa_net_load_rss() RFC: https://lore.kernel.org/all/a54ca70b12ebe2f3c391864e41241697ab1aba30.1691762906.git.yin31...@gmail.com/ net/vhost-vdpa.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c index 7a226c93bc..e59d40b8ae 100644 --- a/net/vhost-vdpa.c +++ b/net/vhost-vdpa.c @@ -818,6 +818,88 @@ static int vhost_vdpa_net_load_mac(VhostVDPAState *s, const VirtIONet *n, return 0; } +static int vhost_vdpa_net_load_rss(VhostVDPAState *s, const VirtIONet *n, + struct iovec *out_cursor, + struct iovec *in_cursor) +{ + struct virtio_net_rss_config cfg = {}; + ssize_t r; + g_autofree uint16_t *table = NULL; + + /* + * According to VirtIO standard, "Initially the device has all hash + * types disabled and reports only VIRTIO_NET_HASH_REPORT_NONE.". + * + * Therefore, there is no need to send this CVQ command if the + * driver disables the all hash types, which aligns with + * the device's defaults. + * + * Note that the device's defaults can mismatch the driver's + * configuration only at live migration. + */ + if (!n->rss_data.enabled || + n->rss_data.hash_types == VIRTIO_NET_HASH_REPORT_NONE) { + return 0; + } + + table = g_malloc_n(n->rss_data.indirections_len, + sizeof(n->rss_data.indirections_table[0])); + cfg.hash_types = cpu_to_le32(n->rss_data.hash_types); + + /* + * According to VirtIO standard, "Field reserved MUST contain zeroes. + * It is defined to make the structure to match the layout of + * virtio_net_rss_config structure, defined in 5.1.6.5.7.". + * + * Therefore, we need to zero the fields in + * struct virtio_net_rss_config, which corresponds to the + * `reserved` field in struct virtio_net_hash_config. + * + * Note that all other fields are zeroed at their definitions, + * except for the `indirection_table` field, where the actual data + * is stored in the `table` variable to ensure compatibility + * with RSS case. Therefore, we need to zero the `table` variable here. + */ + table[0] = 0; + + /* + * Considering that virtio_net_handle_rss() currently does not restore + * the hash key length parsed from the CVQ command sent from the guest + * into n->rss_data and uses the maximum key length in other code, so + * we also employ the maximum key length here. + */ + cfg.hash_key_length = sizeof(n->rss_data.key); + + const struct iovec data[] = { + { + .iov_base = &cfg, + .iov_len = offsetof(struct virtio_net_rss_config, + indirection_table), + }, { + .iov_base = table, + .iov_len = n->rss_data.indirections_len * + sizeof(n->rss_data.indirections_table[0]), + }, { + .iov_base = &cfg.max_tx_vq, + .iov_len = offsetof(struct virtio_net_rss_config, hash_key_data) - + offsetof(struct virtio_net_rss_config, max_tx_vq), + }, { + .iov_base = (void *)n->rss_data.key, + .iov_len = sizeof(n->rss_data.key), + } + }; + + r = vhost_vdpa_net_load_cmd(s, out_cursor, in_cursor, + VIRTIO_NET_CTRL_MQ, + VIRTIO_NET_CTRL_MQ_HASH_CONFIG, + data, ARRAY_SIZE(data)); + if (unlikely(r < 0)) { + return r; + } + + return 0; +} + static int vhost_vdpa_net_load_mq(VhostVDPAState *s, const VirtIONet *n, struct iovec *out_cursor, @@ -843,6 +925,15 @@ static int vhost_vdpa_net_load_mq(VhostVDPAState *s, return r; } + if (!virtio_vdev_has_feature(&n->parent_obj, VIRTIO_NET_F_HASH_REPORT)) { + return 0; + } + + r = vhost_vdpa_net_load_rss(s, n, out_cursor, in_cursor); + if (unlikely(r < 0)) { + return r; + } + return 0; } -- 2.25.1
