Thank you, Alexander. The patch looks good to me. With this patch, do you see other problems with VPP?
I'd like to get a review from @Sam Andrew<mailto:[email protected]>. Acked-by: Long Li <[email protected]> From: Alexander Skorichenko <[email protected]> Sent: Tuesday, July 2, 2024 1:49 AM To: [email protected] Cc: Sam Andrew <[email protected]>; [email protected]; [email protected]; Long Li <[email protected]>; Wei Hu <[email protected]>; [email protected]; Matthew Smith <[email protected]> Subject: Re: [PATCH] net/netvsc: fix mtu_set in netvsc devices You don't often get email from [email protected]<mailto:[email protected]>. Learn why this is important<https://aka.ms/LearnAboutSenderIdentification> Hello, The failure happens when running under VPP. In terms of dpdk calls the following sequence of events occurs for a NetVSC device: Durung device probing stage of VPP 1. eth_hn_dev_init() memory for a single primary rx_queue is allocated dev->data->rx_queues[0] = 0, allocated, but not set yet no allocation happened for tx_queues[i] and non-primary rx_queues[i] During device setup stage of VPP from VPP's own generic dpdk_device_setup(): 2. rte_eth_dev_set_mtu() currently it segfaults in hn_reinit() when trying to reach into dev->data->rx_queues[i], dev->data->tx_queues[i] 3. rte_eth_tx_queue_setup() dev->data->tx_queues[i] are being allocated and set 4. rte_eth_rx_queue_setup() dev->data->rx_queues[i] get allocated (i > 0) and set So rx_queues[0] could be set in step 1, but rx_queues[i] and tx_queues[i] are still NULL. Allocating all the remaining rx/tx queues in step 1 would prevent the crash, but then in steps 3-4 would go through releasing and allocating all of the queues again. Another comment regarding the uniform condition introduced in hn_reinit() in the patch: if (dev->data->rx_queues[0] != NULL) ... Because of the difference between rx/tx queues described above, it's probably safer to extend the condition to check both rx and tx separately if (dev->data->rx_queues[0] != NULL && dev->data->tx_queues[0] != NULL) - Alexander Skorichenko
