On 15/12/2016 12:32, Halil Pasic wrote: > static inline uint16_t vring_avail_idx(VirtQueue *vq) > { > hwaddr pa; > pa = vq->vring.avail + offsetof(VRingAvail, idx); > vq->shadow_avail_idx = virtio_lduw_phys(vq->vdev, pa); > > we should have an endiannes handling here before assigning shadow_avail_idx I > guess > > return vq->shadow_avail_idx; > }
Endianness is already handled: static inline uint16_t virtio_lduw_phys(VirtIODevice *vdev, hwaddr pa) { if (virtio_access_is_big_endian(vdev)) { return lduw_be_phys(&address_space_memory, pa); } return lduw_le_phys(&address_space_memory, pa); } > I will meditate a bit more on this and probably create a patch to fix it. > > What make me wonder is that according to the reports live migration usually > works (ca 1% fails)... What is the backtrace of the vring_avail_idx call? If your device is virtio 1.0, and vdev->guest_features has not been initialized correctly, you might incorrectly treat LE virtio 1.0 data as BE virtio 0.9 data: if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { /* Devices conforming to VIRTIO 1.0 or later are always LE. */ return false; } return true; Thanks, Paolo