Re: [PATCH net v2] Revert "virtio-net: ethtool configurable RXCSUM"
From: Jason Wang
Date: Tue Oct 20 2020 - 02:13:34 EST
On 2020/10/20 上午1:32, Michael S. Tsirkin wrote:
This reverts commit 3618ad2a7c0e78e4258386394d5d5f92a3dbccf8.
When the device does not have a control vq (e.g. when using a
version of QEMU based on upstream v0.10 or older, or when specifying
ctrl_vq=off,ctrl_rx=off,ctrl_vlan=off,ctrl_rx_extra=off,ctrl_mac_addr=off
for the device on the QEMU command line), that commit causes a crash:
[ 72.229171] kernel BUG at drivers/net/virtio_net.c:1667!
[ 72.230266] invalid opcode: 0000 [#1] PREEMPT SMP
[ 72.231172] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.9.0-rc8-02934-g3618ad2a7c0e7 #1
[ 72.231172] EIP: virtnet_send_command+0x120/0x140
[ 72.231172] Code: 00 0f 94 c0 8b 7d f0 65 33 3d 14 00 00 00 75 1c 8d 65 f4 5b 5e 5f 5d c3 66 90 be 01 00 00 00 e9 6e ff ff ff 8d b6 00
+00 00 00 <0f> 0b e8 d9 bb 82 00 eb 17 8d b4 26 00 00 00 00 8d b4 26 00 00 00
[ 72.231172] EAX: 0000000d EBX: f72895c0 ECX: 00000017 EDX: 00000011
[ 72.231172] ESI: f7197800 EDI: ed69bd00 EBP: ed69bcf4 ESP: ed69bc98
[ 72.231172] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010246
[ 72.231172] CR0: 80050033 CR2: 00000000 CR3: 02c84000 CR4: 000406f0
[ 72.231172] Call Trace:
[ 72.231172] ? __virt_addr_valid+0x45/0x60
[ 72.231172] ? ___cache_free+0x51f/0x760
[ 72.231172] ? kobject_uevent_env+0xf4/0x560
[ 72.231172] virtnet_set_guest_offloads+0x4d/0x80
[ 72.231172] virtnet_set_features+0x85/0x120
[ 72.231172] ? virtnet_set_guest_offloads+0x80/0x80
[ 72.231172] __netdev_update_features+0x27a/0x8e0
[ 72.231172] ? kobject_uevent+0xa/0x20
[ 72.231172] ? netdev_register_kobject+0x12c/0x160
[ 72.231172] register_netdevice+0x4fe/0x740
[ 72.231172] register_netdev+0x1c/0x40
[ 72.231172] virtnet_probe+0x728/0xb60
[ 72.231172] ? _raw_spin_unlock+0x1d/0x40
[ 72.231172] ? virtio_vdpa_get_status+0x1c/0x20
[ 72.231172] virtio_dev_probe+0x1c6/0x271
[ 72.231172] really_probe+0x195/0x2e0
[ 72.231172] driver_probe_device+0x26/0x60
[ 72.231172] device_driver_attach+0x49/0x60
[ 72.231172] __driver_attach+0x46/0xc0
[ 72.231172] ? device_driver_attach+0x60/0x60
[ 72.231172] bus_add_driver+0x197/0x1c0
[ 72.231172] driver_register+0x66/0xc0
[ 72.231172] register_virtio_driver+0x1b/0x40
[ 72.231172] virtio_net_driver_init+0x61/0x86
[ 72.231172] ? veth_init+0x14/0x14
[ 72.231172] do_one_initcall+0x76/0x2e4
[ 72.231172] ? rdinit_setup+0x2a/0x2a
[ 72.231172] do_initcalls+0xb2/0xd5
[ 72.231172] kernel_init_freeable+0x14f/0x179
[ 72.231172] ? rest_init+0x100/0x100
[ 72.231172] kernel_init+0xd/0xe0
[ 72.231172] ret_from_fork+0x1c/0x30
[ 72.231172] Modules linked in:
[ 72.269563] ---[ end trace a6ebc4afea0e6cb1 ]---
The reason is that virtnet_set_features now calls virtnet_set_guest_offloads
unconditionally, it used to only call it when there is something
to configure.
If device does not have a control vq, everything breaks.
Looking at this some more, I noticed that it's not really checking the
hardware too much. E.g.
if ((dev->features ^ features) & NETIF_F_LRO) {
if (features & NETIF_F_LRO)
offloads |= GUEST_OFFLOAD_LRO_MASK &
vi->guest_offloads_capable;
else
offloads &= ~GUEST_OFFLOAD_LRO_MASK;
}
and
(1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
(1ULL << VIRTIO_NET_F_GUEST_ECN) | \
(1ULL << VIRTIO_NET_F_GUEST_UFO))
But there's no guarantee that e.g. VIRTIO_NET_F_GUEST_TSO6 is set.
If it isn't command should not send it.
Further
static int virtnet_set_features(struct net_device *dev,
netdev_features_t features)
{
struct virtnet_info *vi = netdev_priv(dev);
u64 offloads = vi->guest_offloads;
seems wrong since guest_offloads is zero initialized,
I'm not sure I get here.
Did you mean vi->guest_offloads?
We initialize it during probe
for (i = 0; i < ARRAY_SIZE(guest_offloads); i++)
if (virtio_has_feature(vi->vdev, guest_offloads[i]))
set_bit(guest_offloads[i], &vi->guest_offloads);
it does not reflect the state after reset which comes from
the features.
Revert the original commit for now.
Cc: Tonghao Zhang <xiangxia.m.yue@xxxxxxxxx>
Cc: Willem de Bruijn <willemb@xxxxxxxxxx>
Fixes: 3618ad2a7c0e7 ("virtio-net: ethtool configurable RXCSUM")
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
changes from v1:
- clarify how to reproduce the bug in the log
drivers/net/virtio_net.c | 50 +++++++++++-----------------------------
1 file changed, 13 insertions(+), 37 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index d2d2c4a53cf2..21b71148c532 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -68,8 +68,6 @@ static const unsigned long guest_offloads[] = {
(1ULL << VIRTIO_NET_F_GUEST_ECN) | \
(1ULL << VIRTIO_NET_F_GUEST_UFO))
-#define GUEST_OFFLOAD_CSUM_MASK (1ULL << VIRTIO_NET_F_GUEST_CSUM)
-
struct virtnet_stat_desc {
char desc[ETH_GSTRING_LEN];
size_t offset;
@@ -2524,48 +2522,29 @@ static int virtnet_get_phys_port_name(struct net_device *dev, char *buf,
return 0;
}
-static netdev_features_t virtnet_fix_features(struct net_device *netdev,
- netdev_features_t features)
-{
- /* If Rx checksum is disabled, LRO should also be disabled. */
- if (!(features & NETIF_F_RXCSUM))
- features &= ~NETIF_F_LRO;
-
- return features;
-}
-
static int virtnet_set_features(struct net_device *dev,
netdev_features_t features)
{
struct virtnet_info *vi = netdev_priv(dev);
- u64 offloads = vi->guest_offloads;
+ u64 offloads;
int err;
- /* Don't allow configuration while XDP is active. */
- if (vi->xdp_queue_pairs)
- return -EBUSY;
-
if ((dev->features ^ features) & NETIF_F_LRO) {
+ if (vi->xdp_queue_pairs)
+ return -EBUSY;
+
if (features & NETIF_F_LRO)
- offloads |= GUEST_OFFLOAD_LRO_MASK &
- vi->guest_offloads_capable;
+ offloads = vi->guest_offloads_capable;
else
- offloads &= ~GUEST_OFFLOAD_LRO_MASK;
+ offloads = vi->guest_offloads_capable &
+ ~GUEST_OFFLOAD_LRO_MASK;
+
+ err = virtnet_set_guest_offloads(vi, offloads);
+ if (err)
+ return err;
+ vi->guest_offloads = offloads;
}
- if ((dev->features ^ features) & NETIF_F_RXCSUM) {
- if (features & NETIF_F_RXCSUM)
- offloads |= GUEST_OFFLOAD_CSUM_MASK &
- vi->guest_offloads_capable;
- else
- offloads &= ~GUEST_OFFLOAD_CSUM_MASK;
- }
-
- err = virtnet_set_guest_offloads(vi, offloads);
- if (err)
- return err;
-
- vi->guest_offloads = offloads;
return 0;
}
@@ -2584,7 +2563,6 @@ static const struct net_device_ops virtnet_netdev = {
.ndo_features_check = passthru_features_check,
.ndo_get_phys_port_name = virtnet_get_phys_port_name,
.ndo_set_features = virtnet_set_features,
- .ndo_fix_features = virtnet_fix_features,
};
static void virtnet_config_changed_work(struct work_struct *work)
@@ -3035,10 +3013,8 @@ static int virtnet_probe(struct virtio_device *vdev)
if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6))
dev->features |= NETIF_F_LRO;
- if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS)) {
- dev->hw_features |= NETIF_F_RXCSUM;
+ if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS))
dev->hw_features |= NETIF_F_LRO;
- }
dev->vlan_features = dev->features;