On 10/08/2020 15:11, Eugenio Pérez wrote:
> Bugzilla bug: 523
>
> Using testpmd as a vhost-user with iommu:
>
> /home/dpdk/build/app/dpdk-testpmd -l 1,3 \
> --vdev net_vhost0,iface=/tmp/vhost-user1,queues=1,iommu-support=1 \
> -- --auto-start --stats-period 5 --forward-mode=txonly
>
> And qemu with packed virtqueue:
>
> <interface type='vhostuser'>
> <mac address='88:67:11:5f:dd:02'/>
> <source type='unix' path='/tmp/vhost-user1' mode='client'/>
> <model type='virtio'/>
> <driver name='vhost' rx_queue_size='1024' iommu='on' ats='on'/>
> <address type='pci' domain='0x0000' bus='0x07' slot='0x00'
> function='0x0'/>
> </interface>
> ...
>
> <qemu:commandline>
> <qemu:arg value='-set'/>
> <qemu:arg value='device.net1.packed=on'/>
> </qemu:commandline>
>
> --
>
> Is it possible to consume the iotlb's entries of the mempoo from different
> threads. Thread sanitizer example output (after change rwlocks to POSIX ones):
>
> WARNING: ThreadSanitizer: data race (pid=76927)
> Write of size 8 at 0x00017ffd5628 by thread T5:
> #0 vhost_user_iotlb_cache_insert ../lib/librte_vhost/iotlb.c:181
> (dpdk-testpmd+0x769343)
> #1 vhost_user_iotlb_msg ../lib/librte_vhost/vhost_user.c:2380
> (dpdk-testpmd+0x78e4bf)
> #2 vhost_user_msg_handler ../lib/librte_vhost/vhost_user.c:2848
> (dpdk-testpmd+0x78fcf8)
> #3 vhost_user_read_cb ../lib/librte_vhost/socket.c:311
> (dpdk-testpmd+0x770162)
> #4 fdset_event_dispatch ../lib/librte_vhost/fd_man.c:286
> (dpdk-testpmd+0x7591c2)
> #5 ctrl_thread_init ../lib/librte_eal/common/eal_common_thread.c:193
> (dpdk-testpmd+0xa2890b)
> #6 <null> <null> (libtsan.so.0+0x2a68d)
>
> Previous read of size 8 at 0x00017ffd5628 by thread T3:
> #0 vhost_user_iotlb_cache_find ../lib/librte_vhost/iotlb.c:252
> (dpdk-testpmd+0x76ee96)
> #1 __vhost_iova_to_vva ../lib/librte_vhost/vhost.c:42
> (dpdk-testpmd+0x77488c)
> #2 vhost_iova_to_vva ../lib/librte_vhost/vhost.h:753
> (dpdk-testpmd+0x7abeb3)
> #3 map_one_desc ../lib/librte_vhost/virtio_net.c:497
> (dpdk-testpmd+0x7abeb3)
> #4 fill_vec_buf_packed ../lib/librte_vhost/virtio_net.c:751
> (dpdk-testpmd+0x7abeb3)
> #5 vhost_enqueue_single_packed ../lib/librte_vhost/virtio_net.c:1170
> (dpdk-testpmd+0x7abeb3)
> #6 virtio_dev_rx_single_packed ../lib/librte_vhost/virtio_net.c:1346
> (dpdk-testpmd+0x7abeb3)
> #7 virtio_dev_rx_packed ../lib/librte_vhost/virtio_net.c:1384
> (dpdk-testpmd+0x7abeb3)
> #8 virtio_dev_rx ../lib/librte_vhost/virtio_net.c:1435
> (dpdk-testpmd+0x7b0654)
> #9 rte_vhost_enqueue_burst ../lib/librte_vhost/virtio_net.c:1465
> (dpdk-testpmd+0x7b0654)
> #10 eth_vhost_tx ../drivers/net/vhost/rte_eth_vhost.c:470
> (dpdk-testpmd+0x1ddfbd8)
> #11 rte_eth_tx_burst ../lib/librte_ethdev/rte_ethdev.h:4800
> (dpdk-testpmd+0x505fdb)
> #12 pkt_burst_transmit ../app/test-pmd/txonly.c:365
> (dpdk-testpmd+0x5106ad)
> #13 run_pkt_fwd_on_lcore ../app/test-pmd/testpmd.c:2080
> (dpdk-testpmd+0x4f8951)
> #14 start_pkt_forward_on_core ../app/test-pmd/testpmd.c:2106
> (dpdk-testpmd+0x4f89d7)
> #15 eal_thread_loop ../lib/librte_eal/linux/eal_thread.c:127
> (dpdk-testpmd+0xa5b20a)
> #16 <null> <null> (libtsan.so.0+0x2a68d)
>
> Location is global '<null>' at 0x000000000000 (rtemap_0+0x00003ffd5628)
>
> Thread T5 'vhost-events' (tid=76933, running) created by main thread at:
> #0 pthread_create <null> (libtsan.so.0+0x2cd42)
> #1 rte_ctrl_thread_create
> ../lib/librte_eal/common/eal_common_thread.c:216 (dpdk-testpmd+0xa289e7)
> #2 rte_vhost_driver_start ../lib/librte_vhost/socket.c:1190
> (dpdk-testpmd+0x7728ef)
> #3 vhost_driver_setup ../drivers/net/vhost/rte_eth_vhost.c:1028
> (dpdk-testpmd+0x1de233d)
> #4 eth_dev_configure ../drivers/net/vhost/rte_eth_vhost.c:1126
> (dpdk-testpmd+0x1de29cc)
> #5 rte_eth_dev_configure ../lib/librte_ethdev/rte_ethdev.c:1439
> (dpdk-testpmd+0x991ce2)
> #6 start_port ../app/test-pmd/testpmd.c:2450 (dpdk-testpmd+0x4f9b45)
> #7 main ../app/test-pmd/testpmd.c:3777 (dpdk-testpmd+0x4fe1ac)
>
> Thread T3 'lcore-slave-3' (tid=76931, running) created by main thread at:
> #0 pthread_create <null> (libtsan.so.0+0x2cd42)
> #1 rte_eal_init ../lib/librte_eal/linux/eal.c:1244 (dpdk-testpmd+0xa46e2b)
> #2 main ../app/test-pmd/testpmd.c:3673 (dpdk-testpmd+0x4fdd75)
>
> --
>
> Or:
> WARNING: ThreadSanitizer: data race (pid=76927)
> Write of size 1 at 0x00017ffd00f8 by thread T5:
> #0 vhost_user_iotlb_cache_insert ../lib/librte_vhost/iotlb.c:182
> (dpdk-testpmd+0x769370)
> #1 vhost_user_iotlb_msg ../lib/librte_vhost/vhost_user.c:2380
> (dpdk-testpmd+0x78e4bf)
> #2 vhost_user_msg_handler ../lib/librte_vhost/vhost_user.c:2848
> (dpdk-testpmd+0x78fcf8)
> #3 vhost_user_read_cb ../lib/librte_vhost/socket.c:311
> (dpdk-testpmd+0x770162)
> #4 fdset_event_dispatch ../lib/librte_vhost/fd_man.c:286
> (dpdk-testpmd+0x7591c2)
> #5 ctrl_thread_init ../lib/librte_eal/common/eal_common_thread.c:193
> (dpdk-testpmd+0xa2890b)
> #6 <null> <null> (libtsan.so.0+0x2a68d)
>
> Previous write of size 1 at 0x00017ffd00f8 by thread T3:
> #0 vhost_user_iotlb_pending_insert ../lib/librte_vhost/iotlb.c:86
> (dpdk-testpmd+0x75eb0c)
> #1 __vhost_iova_to_vva ../lib/librte_vhost/vhost.c:58
> (dpdk-testpmd+0x774926)
> #2 vhost_iova_to_vva ../lib/librte_vhost/vhost.h:753
> (dpdk-testpmd+0x7a79d1)
> #3 virtio_dev_rx_batch_packed ../lib/librte_vhost/virtio_net.c:1295
> (dpdk-testpmd+0x7a79d1)
> #4 virtio_dev_rx_packed ../lib/librte_vhost/virtio_net.c:1376
> (dpdk-testpmd+0x7a79d1)
> #5 virtio_dev_rx ../lib/librte_vhost/virtio_net.c:1435
> (dpdk-testpmd+0x7b0654)
> #6 rte_vhost_enqueue_burst ../lib/librte_vhost/virtio_net.c:1465
> (dpdk-testpmd+0x7b0654)
> #7 eth_vhost_tx ../drivers/net/vhost/rte_eth_vhost.c:470
> (dpdk-testpmd+0x1ddfbd8)
> #8 rte_eth_tx_burst ../lib/librte_ethdev/rte_ethdev.h:4800
> (dpdk-testpmd+0x505fdb)
> #9 pkt_burst_transmit ../app/test-pmd/txonly.c:365 (dpdk-testpmd+0x5106ad)
> #10 run_pkt_fwd_on_lcore ../app/test-pmd/testpmd.c:2080
> (dpdk-testpmd+0x4f8951)
> #11 start_pkt_forward_on_core ../app/test-pmd/testpmd.c:2106
> (dpdk-testpmd+0x4f89d7)
> #12 eal_thread_loop ../lib/librte_eal/linux/eal_thread.c:127
> (dpdk-testpmd+0xa5b20a)
> #13 <null> <null> (libtsan.so.0+0x2a68d)
>
> --
>
> As a consequence, the two threads can modify the same entry of the mempool.
> Usually, this cause a loop in iotlb_pending_entries list.
>
> Fixes: d012d1f293f4 ("vhost: add IOTLB helper functions")
> Signed-off-by: Eugenio Pérez <epere...@redhat.com>
> ---
> lib/librte_vhost/iotlb.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/lib/librte_vhost/iotlb.c b/lib/librte_vhost/iotlb.c
> index 5b3a0c090..e0b67721b 100644
> --- a/lib/librte_vhost/iotlb.c
> +++ b/lib/librte_vhost/iotlb.c
> @@ -321,8 +321,7 @@ vhost_user_iotlb_init(struct virtio_net *dev, int
> vq_index)
> IOTLB_CACHE_SIZE, sizeof(struct vhost_iotlb_entry), 0,
> 0, 0, NULL, NULL, NULL, socket,
> MEMPOOL_F_NO_CACHE_ALIGN |
> - MEMPOOL_F_SP_PUT |
> - MEMPOOL_F_SC_GET);
> + MEMPOOL_F_SP_PUT);
> if (!vq->iotlb_pool) {
> VHOST_LOG_CONFIG(ERR,
> "Failed to create IOTLB cache pool (%s)\n",
>
Looks ok to me, but would need review from vhost maintainer.
