Messages in this thread Patch in this message | | | From | Hawkins Jiawei <> | Subject | [PATCH] virtio-net: Zero max_tx_vq field for VIRTIO_NET_CTRL_MQ_HASH_CONFIG case | Date | Thu, 10 Aug 2023 11:15:57 +0800 |
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Kernel uses `struct virtio_net_ctrl_rss` to save command-specific-data for both the VIRTIO_NET_CTRL_MQ_HASH_CONFIG and VIRTIO_NET_CTRL_MQ_RSS_CONFIG commands.
According to the 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.".
Yet for the VIRTIO_NET_CTRL_MQ_HASH_CONFIG command case, the `max_tx_vq` field in struct virtio_net_ctrl_rss, which corresponds to the `reserved` field in struct virtio_net_hash_config, is not zeroed, thereby violating the VirtIO standard.
This patch solves this problem by zeroing this field in virtnet_init_default_rss().
Signed-off-by: Hawkins Jiawei <yin31149@gmail.com> ---
TestStep ======== 1. Boot QEMU with one virtio-net-pci net device with `mq` and `hash` feature on, command line like: -netdev tap,vhost=off,... -device virtio-net-pci,mq=on,hash=on,...
2. Trigger VIRTIO_NET_CTRL_MQ_HASH_CONFIG command in guest, command line like: ethtool -K eth0 rxhash on
Without this patch, in virtnet_commit_rss_command(), we can see the `max_tx_vq` field is 1 in gdb like below:
pwndbg> p vi->ctrl->rss $1 = { hash_types = 63, indirection_table_mask = 0, unclassified_queue = 0, indirection_table = {0 <repeats 128 times>}, max_tx_vq = 1, hash_key_length = 40 '(', ... }
With this patch, in virtnet_commit_rss_command(), we can see the `max_tx_vq` field is 0 in gdb like below:
pwndbg> p vi->ctrl->rss $1 = { hash_types = 63, indirection_table_mask = 0, unclassified_queue = 0, indirection_table = {0 <repeats 128 times>}, max_tx_vq = 0, hash_key_length = 40 '(', ... }
drivers/net/virtio_net.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 1270c8d23463..8db38634ae82 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -2761,7 +2761,7 @@ static void virtnet_init_default_rss(struct virtnet_info *vi) vi->ctrl->rss.indirection_table[i] = indir_val; } - vi->ctrl->rss.max_tx_vq = vi->curr_queue_pairs; + vi->ctrl->rss.max_tx_vq = vi->has_rss ? vi->curr_queue_pairs : 0; vi->ctrl->rss.hash_key_length = vi->rss_key_size; netdev_rss_key_fill(vi->ctrl->rss.key, vi->rss_key_size); -- 2.34.1
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