mir/ovs
2
0
Fork 0
mirror of https://github.com/openvswitch/ovs synced 2025-08-31 14:25:26 +00:00
Code Issues Releases Wiki Activity

netdev-dpdk: Drop TSO in case of conflicting virtio features.

Browse Source 
At some point in OVS history, some virtio features were announced as
supported (ECN and UFO virtio features).

The userspace TSO code, which has been added later, does not support
those features and tries to disable them.

This breaks OVS upgrades: if an existing VM already negotiated such
features, their lack on reconnection to an upgraded OVS triggers a
vhost socket disconnection by Qemu.
This results in an endless loop because Qemu then retries with the same
set of virtio features.

This patch proposes to try and detect those vhost socket disconnection
and fallback restoring the old virtio features (and disabling TSO for
this vhost port).

Acked-by: Mike Pattrick <mkp@redhat.com>
Acked-by: Simon Horman <simon.horman@corigine.com>
Acked-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Signed-off-by: David Marchand <david.marchand@redhat.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
This commit is contained in:
David Marchand
2023-07-07 15:59:23 +02:00
committed by Ilya Maximets
parent b4c7009c20
commit a5669fd51c
2 changed files with 120 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

100
lib/netdev-dpdk.c
View File

@@ -418,6 +418,18 @@ enum dpdk_hw_ol_features {
NETDEV_TX_TSO_OFFLOAD = 1 << 7,
};
/* Flags for the netdev_dpdk virtio_features_state field.
* This is used for the virtio features recovery mechanism linked to TSO
* support. */
#define OVS_VIRTIO_F_CLEAN (UINT8_C(1) << 0)
#define OVS_VIRTIO_F_WORKAROUND (UINT8_C(1) << 1)
#define OVS_VIRTIO_F_NEGOTIATED (UINT8_C(1) << 2)
#define OVS_VIRTIO_F_RECONF_PENDING (UINT8_C(1) << 3)
#define OVS_VIRTIO_F_CLEAN_NEGOTIATED \
(OVS_VIRTIO_F_CLEAN | OVS_VIRTIO_F_NEGOTIATED)
#define OVS_VIRTIO_F_WORKAROUND_NEGOTIATED \
(OVS_VIRTIO_F_WORKAROUND | OVS_VIRTIO_F_NEGOTIATED)
/*
* In order to avoid confusion in variables names, following naming convention
* should be used, if possible:
@@ -474,7 +486,11 @@ struct netdev_dpdk {
bool vhost_reconfigured;
atomic_uint8_t vhost_tx_retries_max;
/* 2 pad bytes here. */
/* Flags for virtio features recovery mechanism. */
uint8_t virtio_features_state;
/* 1 pad byte here. */
);
PADDED_MEMBERS(CACHE_LINE_SIZE,
@@ -1359,6 +1375,7 @@ common_construct(struct netdev *netdev, dpdk_port_t port_no,
dev->requested_lsc_interrupt_mode = 0;
ovsrcu_index_init(&dev->vid, -1);
dev->vhost_reconfigured = false;
dev->virtio_features_state = OVS_VIRTIO_F_CLEAN;
dev->attached = false;
dev->started = false;
dev->reset_needed = false;
@@ -3883,6 +3900,12 @@ netdev_dpdk_vhost_user_get_status(const struct netdev *netdev,
xasprintf("%d", vring.size));
}
if (userspace_tso_enabled()
&& dev->virtio_features_state & OVS_VIRTIO_F_WORKAROUND) {
smap_add_format(args, "userspace-tso", "disabled");
}
ovs_mutex_unlock(&dev->mutex);
return 0;
}
@@ -4245,6 +4268,8 @@ new_device(int vid)
newnode = dev->socket_id;
}
dev->virtio_features_state |= OVS_VIRTIO_F_NEGOTIATED;
if (dev->requested_n_txq < qp_num
|| dev->requested_n_rxq < qp_num
|| dev->requested_socket_id != newnode
@@ -4268,7 +4293,9 @@ new_device(int vid)
dev->hw_ol_features |= NETDEV_TX_SCTP_CKSUM_OFFLOAD;
}
if (userspace_tso_enabled()) {
if (userspace_tso_enabled()
&& dev->virtio_features_state & OVS_VIRTIO_F_CLEAN) {
if (features & (1ULL << VIRTIO_NET_F_GUEST_TSO4)
&& features & (1ULL << VIRTIO_NET_F_GUEST_TSO6)) {
@@ -4524,6 +4551,45 @@ destroy_connection(int vid)
dev->requested_n_txq = qp_num;
netdev_request_reconfigure(&dev->up);
}
if (!(dev->virtio_features_state & OVS_VIRTIO_F_NEGOTIATED)) {
/* The socket disconnected before reaching new_device. It
* likely means that the guest did not agree with the virtio
* features. */
VLOG_WARN_RL(&rl, "Connection on socket '%s' closed during "
"initialization.", dev->vhost_id);
}
if (!(dev->virtio_features_state & OVS_VIRTIO_F_RECONF_PENDING)) {
switch (dev->virtio_features_state) {
case OVS_VIRTIO_F_CLEAN:
dev->virtio_features_state = OVS_VIRTIO_F_WORKAROUND;
break;
case OVS_VIRTIO_F_WORKAROUND:
dev->virtio_features_state = OVS_VIRTIO_F_CLEAN;
break;
case OVS_VIRTIO_F_CLEAN_NEGOTIATED:
/* The virtio features were clean and got accepted by the
* guest. We expect it will be the case in the future and
* change nothing. */
break;
case OVS_VIRTIO_F_WORKAROUND_NEGOTIATED:
/* Let's try to go with clean virtio features on a next
* connection. */
dev->virtio_features_state = OVS_VIRTIO_F_CLEAN;
break;
default:
OVS_NOT_REACHED();
}
if (!(dev->virtio_features_state & OVS_VIRTIO_F_NEGOTIATED)) {
dev->virtio_features_state |= OVS_VIRTIO_F_RECONF_PENDING;
netdev_request_reconfigure(&dev->up);
}
}
ovs_mutex_unlock(&dev->mutex);
exists = true;
break;
@@ -5454,10 +5520,31 @@ static int
netdev_dpdk_vhost_client_reconfigure(struct netdev *netdev)
{
struct netdev_dpdk *dev = netdev_dpdk_cast(netdev);
bool unregister = false;
char *vhost_id;
int err;
ovs_mutex_lock(&dev->mutex);
if (dev->vhost_driver_flags & RTE_VHOST_USER_CLIENT && dev->vhost_id
&& dev->virtio_features_state & OVS_VIRTIO_F_RECONF_PENDING) {
/* This vhost-user port was registered to the vhost library already,
* but a socket disconnection happened and configuration must be
* re-evaluated wrt dev->virtio_features_state. */
dev->vhost_driver_flags &= ~RTE_VHOST_USER_CLIENT;
vhost_id = dev->vhost_id;
unregister = true;
}
ovs_mutex_unlock(&dev->mutex);
if (unregister) {
dpdk_vhost_driver_unregister(dev, vhost_id);
}
ovs_mutex_lock(&dev->mutex);
/* Configure vHost client mode if requested and if the following criteria
* are met:
* 1. Device hasn't been registered yet.
@@ -5466,6 +5553,11 @@ netdev_dpdk_vhost_client_reconfigure(struct netdev *netdev)
if (!(dev->vhost_driver_flags & RTE_VHOST_USER_CLIENT) && dev->vhost_id) {
uint64_t virtio_unsup_features = 0;
uint64_t vhost_flags = 0;
bool enable_tso;
enable_tso = userspace_tso_enabled()
&& dev->virtio_features_state & OVS_VIRTIO_F_CLEAN;
dev->virtio_features_state &= ~OVS_VIRTIO_F_RECONF_PENDING;
/* Register client-mode device. */
vhost_flags |= RTE_VHOST_USER_CLIENT;
@@ -5487,7 +5579,7 @@ netdev_dpdk_vhost_client_reconfigure(struct netdev *netdev)
}
/* Enable External Buffers if TCP Segmentation Offload is enabled. */
if (userspace_tso_enabled()) {
if (enable_tso) {
vhost_flags |= RTE_VHOST_USER_EXTBUF_SUPPORT;
}
@@ -5512,7 +5604,7 @@ netdev_dpdk_vhost_client_reconfigure(struct netdev *netdev)
goto unlock;
}
if (userspace_tso_enabled()) {
if (enable_tso) {
virtio_unsup_features = 1ULL << VIRTIO_NET_F_HOST_ECN
| 1ULL << VIRTIO_NET_F_HOST_UFO;
VLOG_DBG("%s: TSO enabled on vhost port",