110 lines
6.4 KiB
Diff
110 lines
6.4 KiB
Diff
From 521a1953bc11ab6823dcbbee773bcf86e926a9e7 Mon Sep 17 00:00:00 2001
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From: Si-Wei Liu <si-wei.liu@oracle.com>
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Date: Fri, 6 May 2022 19:28:18 -0700
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Subject: [PATCH 14/16] virtio-net: don't handle mq request in userspace
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handler for vhost-vdpa
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Jason Wang <jasowang@redhat.com>
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RH-MergeRequest: 98: Multiqueue fixes for vhost-vDPA
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RH-Commit: [7/7] 9781cab45448ae16a00fbf10cf7995df6b984a0a (jasowang/qemu-kvm-cs)
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RH-Bugzilla: 2070804
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RH-Acked-by: Eugenio Pérez <eperezma@redhat.com>
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RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
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RH-Acked-by: Cindy Lu <lulu@redhat.com>
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virtio_queue_host_notifier_read() tends to read pending event
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left behind on ioeventfd in the vhost_net_stop() path, and
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attempts to handle outstanding kicks from userspace vq handler.
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However, in the ctrl_vq handler, virtio_net_handle_mq() has a
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recursive call into virtio_net_set_status(), which may lead to
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segmentation fault as shown in below stack trace:
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0 0x000055f800df1780 in qdev_get_parent_bus (dev=0x0) at ../hw/core/qdev.c:376
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1 0x000055f800c68ad8 in virtio_bus_device_iommu_enabled (vdev=vdev@entry=0x0) at ../hw/virtio/virtio-bus.c:331
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2 0x000055f800d70d7f in vhost_memory_unmap (dev=<optimized out>) at ../hw/virtio/vhost.c:318
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3 0x000055f800d70d7f in vhost_memory_unmap (dev=<optimized out>, buffer=0x7fc19bec5240, len=2052, is_write=1, access_len=2052) at ../hw/virtio/vhost.c:336
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4 0x000055f800d71867 in vhost_virtqueue_stop (dev=dev@entry=0x55f8037ccc30, vdev=vdev@entry=0x55f8044ec590, vq=0x55f8037cceb0, idx=0) at ../hw/virtio/vhost.c:1241
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5 0x000055f800d7406c in vhost_dev_stop (hdev=hdev@entry=0x55f8037ccc30, vdev=vdev@entry=0x55f8044ec590) at ../hw/virtio/vhost.c:1839
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6 0x000055f800bf00a7 in vhost_net_stop_one (net=0x55f8037ccc30, dev=0x55f8044ec590) at ../hw/net/vhost_net.c:315
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7 0x000055f800bf0678 in vhost_net_stop (dev=dev@entry=0x55f8044ec590, ncs=0x55f80452bae0, data_queue_pairs=data_queue_pairs@entry=7, cvq=cvq@entry=1)
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at ../hw/net/vhost_net.c:423
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8 0x000055f800d4e628 in virtio_net_set_status (status=<optimized out>, n=0x55f8044ec590) at ../hw/net/virtio-net.c:296
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9 0x000055f800d4e628 in virtio_net_set_status (vdev=vdev@entry=0x55f8044ec590, status=15 '\017') at ../hw/net/virtio-net.c:370
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10 0x000055f800d534d8 in virtio_net_handle_ctrl (iov_cnt=<optimized out>, iov=<optimized out>, cmd=0 '\000', n=0x55f8044ec590) at ../hw/net/virtio-net.c:1408
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11 0x000055f800d534d8 in virtio_net_handle_ctrl (vdev=0x55f8044ec590, vq=0x7fc1a7e888d0) at ../hw/net/virtio-net.c:1452
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12 0x000055f800d69f37 in virtio_queue_host_notifier_read (vq=0x7fc1a7e888d0) at ../hw/virtio/virtio.c:2331
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13 0x000055f800d69f37 in virtio_queue_host_notifier_read (n=n@entry=0x7fc1a7e8894c) at ../hw/virtio/virtio.c:3575
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14 0x000055f800c688e6 in virtio_bus_cleanup_host_notifier (bus=<optimized out>, n=n@entry=14) at ../hw/virtio/virtio-bus.c:312
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15 0x000055f800d73106 in vhost_dev_disable_notifiers (hdev=hdev@entry=0x55f8035b51b0, vdev=vdev@entry=0x55f8044ec590)
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at ../../../include/hw/virtio/virtio-bus.h:35
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16 0x000055f800bf00b2 in vhost_net_stop_one (net=0x55f8035b51b0, dev=0x55f8044ec590) at ../hw/net/vhost_net.c:316
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17 0x000055f800bf0678 in vhost_net_stop (dev=dev@entry=0x55f8044ec590, ncs=0x55f80452bae0, data_queue_pairs=data_queue_pairs@entry=7, cvq=cvq@entry=1)
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at ../hw/net/vhost_net.c:423
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18 0x000055f800d4e628 in virtio_net_set_status (status=<optimized out>, n=0x55f8044ec590) at ../hw/net/virtio-net.c:296
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19 0x000055f800d4e628 in virtio_net_set_status (vdev=0x55f8044ec590, status=15 '\017') at ../hw/net/virtio-net.c:370
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20 0x000055f800d6c4b2 in virtio_set_status (vdev=0x55f8044ec590, val=<optimized out>) at ../hw/virtio/virtio.c:1945
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21 0x000055f800d11d9d in vm_state_notify (running=running@entry=false, state=state@entry=RUN_STATE_SHUTDOWN) at ../softmmu/runstate.c:333
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22 0x000055f800d04e7a in do_vm_stop (state=state@entry=RUN_STATE_SHUTDOWN, send_stop=send_stop@entry=false) at ../softmmu/cpus.c:262
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23 0x000055f800d04e99 in vm_shutdown () at ../softmmu/cpus.c:280
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24 0x000055f800d126af in qemu_cleanup () at ../softmmu/runstate.c:812
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25 0x000055f800ad5b13 in main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>) at ../softmmu/main.c:51
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For now, temporarily disable handling MQ request from the ctrl_vq
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userspace hanlder to avoid the recursive virtio_net_set_status()
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call. Some rework is needed to allow changing the number of
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queues without going through a full virtio_net_set_status cycle,
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particularly for vhost-vdpa backend.
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This patch will need to be reverted as soon as future patches of
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having the change of #queues handled in userspace is merged.
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Fixes: 402378407db ("vhost-vdpa: multiqueue support")
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Signed-off-by: Si-Wei Liu <si-wei.liu@oracle.com>
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Acked-by: Jason Wang <jasowang@redhat.com>
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Message-Id: <1651890498-24478-8-git-send-email-si-wei.liu@oracle.com>
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Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
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Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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(cherry picked from commit 2a7888cc3aa31faee839fa5dddad354ff8941f4c)
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Signed-off-by: Jason Wang <jasowang@redhat.com>
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---
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hw/net/virtio-net.c | 13 +++++++++++++
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1 file changed, 13 insertions(+)
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diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
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index f0bb29c741..099e65036d 100644
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--- a/hw/net/virtio-net.c
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+++ b/hw/net/virtio-net.c
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@@ -1381,6 +1381,7 @@ static int virtio_net_handle_mq(VirtIONet *n, uint8_t cmd,
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{
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VirtIODevice *vdev = VIRTIO_DEVICE(n);
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uint16_t queue_pairs;
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+ NetClientState *nc = qemu_get_queue(n->nic);
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virtio_net_disable_rss(n);
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if (cmd == VIRTIO_NET_CTRL_MQ_HASH_CONFIG) {
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@@ -1412,6 +1413,18 @@ static int virtio_net_handle_mq(VirtIONet *n, uint8_t cmd,
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return VIRTIO_NET_ERR;
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}
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+ /* Avoid changing the number of queue_pairs for vdpa device in
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+ * userspace handler. A future fix is needed to handle the mq
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+ * change in userspace handler with vhost-vdpa. Let's disable
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+ * the mq handling from userspace for now and only allow get
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+ * done through the kernel. Ripples may be seen when falling
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+ * back to userspace, but without doing it qemu process would
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+ * crash on a recursive entry to virtio_net_set_status().
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+ */
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+ if (nc->peer && nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_VDPA) {
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+ return VIRTIO_NET_ERR;
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+ }
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+
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n->curr_queue_pairs = queue_pairs;
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/* stop the backend before changing the number of queue_pairs to avoid handling a
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* disabled queue */
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--
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2.31.1
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