On Mon, Nov 16, 2020 at 11:37:48AM +0800, Jason Wang wrote:
On 2020/11/13 下午9:47, Stefano Garzarella wrote:Thanks to Max that started this work! I took his patches, and extended the block simulator a bit. This series moves the network device simulator in a new module (vdpa_sim_net) and leaves the generic functions in the vdpa_sim core module, allowing the possibility to add new vDPA device simulators. Then we added a new vdpa_sim_blk module to simulate a block device. I'm not sure about patch 11 ("vringh: allow vringh_iov_xfer() to skip bytes when ptr is NULL"), maybe we can add a new functions instead of modify vringh_iov_xfer(). As Max reported, I'm also seeing errors with vdpa_sim_blk related to iotlb and vringh when there is high load, these are some of the error messages I can see randomly: vringh: Failed to access avail idx at 00000000e8deb2cc vringh: Failed to read head: idx 6289 address 00000000e1ad1d50 vringh: Failed to get flags at 000000006635d7a3 virtio_vdpa vdpa0: vringh_iov_push_iotlb() error: -14 offset: 0x2840000 len: 0x20000 virtio_vdpa vdpa0: vringh_iov_pull_iotlb() error: -14 offset: 0x58ee000 len: 0x3000 These errors should all be related to the fact that iotlb_translate() fails with -EINVAL, so it seems that we miss some mapping.Is this only reproducible when there's multiple co-current accessing of IOTLB? If yes, it's probably a hint that some kind of synchronization is still missed somewhere.
Yeah, maybe this is the case where virtio_ring and vringh use IOTLB concorrentetively.
It might be useful to log the dma_map/unmp in both virtio_ring and vringh to see who is missing the map.
I'll try. Thanks for the hints, Stefano
