From 2e9ca760c289e1f992eb2cd053e217db7934ab0a Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Tue, 16 Aug 2022 01:36:27 -0400 Subject: [PATCH] virtio_net: Revert "virtio_net: set the default max ring size by find_vqs()" This reverts commit 762faee5a2678559d3dc09d95f8f2c54cd0466a7. This has been reported to trip up guests on GCP (Google Cloud). The reason is that virtio_find_vqs_ctx_size is broken on legacy devices. We can in theory fix virtio_find_vqs_ctx_size but in fact the patch itself has several other issues: - It treats unknown speed as < 10G - It leaves userspace no way to find out the ring size set by hypervisor - It tests speed when link is down - It ignores the virtio spec advice: Both \field{speed} and \field{duplex} can change, thus the driver is expected to re-read these values after receiving a configuration change notification. - It is not clear the performance impact has been tested properly Revert the patch for now. Reported-by: Andres Freund Link: https://lore.kernel.org/r/20220814212610.GA3690074%40roeck-us.net Link: https://lore.kernel.org/r/20220815070203.plwjx7b3cyugpdt7%40awork3.anarazel.de Link: https://lore.kernel.org/r/3df6bb82-1951-455d-a768-e9e1513eb667%40www.fastmail.com Link: https://lore.kernel.org/r/FCDC5DDE-3CDD-4B8A-916F-CA7D87B547CE%40anarazel.de Fixes: 762faee5a267 ("virtio_net: set the default max ring size by find_vqs()") Cc: Xuan Zhuo Cc: Jason Wang Signed-off-by: Michael S. Tsirkin Tested-by: Andres Freund Tested-by: Guenter Roeck Message-Id: <20220816053602.173815-2-mst@redhat.com> --- drivers/net/virtio_net.c | 42 ++++------------------------------------ 1 file changed, 4 insertions(+), 38 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index d934774e9733..ece00b84e3a7 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -3432,29 +3432,6 @@ static unsigned int mergeable_min_buf_len(struct virtnet_info *vi, struct virtqu (unsigned int)GOOD_PACKET_LEN); } -static void virtnet_config_sizes(struct virtnet_info *vi, u32 *sizes) -{ - u32 i, rx_size, tx_size; - - if (vi->speed == SPEED_UNKNOWN || vi->speed < SPEED_10000) { - rx_size = 1024; - tx_size = 1024; - - } else if (vi->speed < SPEED_40000) { - rx_size = 1024 * 4; - tx_size = 1024 * 4; - - } else { - rx_size = 1024 * 8; - tx_size = 1024 * 8; - } - - for (i = 0; i < vi->max_queue_pairs; i++) { - sizes[rxq2vq(i)] = rx_size; - sizes[txq2vq(i)] = tx_size; - } -} - static int virtnet_find_vqs(struct virtnet_info *vi) { vq_callback_t **callbacks; @@ -3462,7 +3439,6 @@ static int virtnet_find_vqs(struct virtnet_info *vi) int ret = -ENOMEM; int i, total_vqs; const char **names; - u32 *sizes; bool *ctx; /* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by @@ -3490,15 +3466,10 @@ static int virtnet_find_vqs(struct virtnet_info *vi) ctx = NULL; } - sizes = kmalloc_array(total_vqs, sizeof(*sizes), GFP_KERNEL); - if (!sizes) - goto err_sizes; - /* Parameters for control virtqueue, if any */ if (vi->has_cvq) { callbacks[total_vqs - 1] = NULL; names[total_vqs - 1] = "control"; - sizes[total_vqs - 1] = 64; } /* Allocate/initialize parameters for send/receive virtqueues */ @@ -3513,10 +3484,8 @@ static int virtnet_find_vqs(struct virtnet_info *vi) ctx[rxq2vq(i)] = true; } - virtnet_config_sizes(vi, sizes); - - ret = virtio_find_vqs_ctx_size(vi->vdev, total_vqs, vqs, callbacks, - names, sizes, ctx, NULL); + ret = virtio_find_vqs_ctx(vi->vdev, total_vqs, vqs, callbacks, + names, ctx, NULL); if (ret) goto err_find; @@ -3536,8 +3505,6 @@ static int virtnet_find_vqs(struct virtnet_info *vi) err_find: - kfree(sizes); -err_sizes: kfree(ctx); err_ctx: kfree(names); @@ -3897,9 +3864,6 @@ static int virtnet_probe(struct virtio_device *vdev) vi->curr_queue_pairs = num_online_cpus(); vi->max_queue_pairs = max_queue_pairs; - virtnet_init_settings(dev); - virtnet_update_settings(vi); - /* Allocate/initialize the rx/tx queues, and invoke find_vqs */ err = init_vqs(vi); if (err) @@ -3912,6 +3876,8 @@ static int virtnet_probe(struct virtio_device *vdev) netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs); netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs); + virtnet_init_settings(dev); + if (virtio_has_feature(vdev, VIRTIO_NET_F_STANDBY)) { vi->failover = net_failover_create(vi->dev); if (IS_ERR(vi->failover)) { -- 2.20.1