diff options
Diffstat (limited to 'results/classifier/deepseek-2-tmp/output/network/1924603')
| -rw-r--r-- | results/classifier/deepseek-2-tmp/output/network/1924603 | 52 |
1 files changed, 0 insertions, 52 deletions
diff --git a/results/classifier/deepseek-2-tmp/output/network/1924603 b/results/classifier/deepseek-2-tmp/output/network/1924603 deleted file mode 100644 index 4d922e39..00000000 --- a/results/classifier/deepseek-2-tmp/output/network/1924603 +++ /dev/null @@ -1,52 +0,0 @@ - -Incorrect feature negotiation for vhost-vdpa netdevice - -QEMU cmdline: -============= -./x86_64-softmmu/qemu-system-x86_64 -machine accel=kvm -m 2G -hda /gautam/centos75_1.qcow2 -name gautam,process=gautam -enable-kvm -netdev vhost-vdpa,id=mynet0,vhostdev=/dev/vhost-vdpa-0 -device virtio-net-pci,netdev=mynet0,mac=02:AA:BB:DD:00:20,disable-modern=off,page-per-vq=on -cpu host --nographic - -Host OS: -======== -Linux kernel 5.11 running on x86 host - -Guest OS: -========== -CentOS 7.5 - -Root cause analysis: -===================== - -For vhost-vdpa netdevice, the feature negotiation results in sending the superset of features received from device in call to get_features vdpa ops callback. - -During the feature-negotiation phase, the acknowledged feature bits are initialized with backend_features and then checked for supported feature bits in vhost_ack_features(): - -void vhost_net_ack_features(struct vhost_net *net, uint64_t features) -{ - net->dev.acked_features = net->dev.backend_features; - vhost_ack_features(&net->dev, vhost_net_get_feature_bits(net), features); -} - - -The vhost_ack_features() function just builds up on the dev.acked_features and never trims it down: - -void vhost_ack_features(struct vhost_dev *hdev, const int *feature_bits, uint64_t features) -{ const int *bit = feature_bits; - - while (*bit != VHOST_INVALID_FEATURE_BIT) { - uint64_t bit_mask = (1ULL << *bit); - - if (features & bit_mask) - hdev->acked_features |= bit_mask; - - bit++; - } -} - -Because of this hdev->acked_features is always minimally equal to the value of device features and this is the value that is passed to the device in set_features callback: - -static int vhost_dev_set_features(struct vhost_dev *dev, bool enable_log) -{ - uint64_t *features = dev->acked_features; - ..... - r = dev->vhost_ops->*vhost_set_features*(dev, features); -} \ No newline at end of file |