On Wed, Jan 11, 2023 at 9:33 PM Eli Cohen <elic@xxxxxxxxxx> wrote: > > > From: Jason Wang <jasowang@xxxxxxxxxx> > > Sent: Wednesday, 11 January 2023 8:28 > > To: mst@xxxxxxxxxx; jasowang@xxxxxxxxxx > > Cc: Eli Cohen <elic@xxxxxxxxxx>; gdawar@xxxxxxx; > > virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > > tanuj.kamde@xxxxxxx > > Subject: [PATCH 0/5] virtio_ring: per virtqueue DMA device > > > > Hi All: > > > > In some cases, the virtqueue could be backed by different devices. One > > example is that in the case of vDPA some parent may emualte virtqueue > > via vringh. In this case, it would be wrong if we stick with the > > physical DMA device for software emulated device, since there's no > > easy way for vringh to know about the hardware IOMMU mappings. > > > > So this series tries to introduce per virtqueue DMA device, then > > software virtqueues can utilize the transport specific method to > > assign appropirate DMA device. > > > > This fixes the crash of mlx5_vdpa + virtio_vdpa when platform IOMMU is > > enabled but not in the passthrough mode. The reason for the crash is > > that the virito_ring tries to map the control virtqueue into platform > > IOMMU but the vringh assumes a direct mapping (PA as IOVA). This is > > fixed by advetise the vDPA device that doesnt do DMA (without a DMA > > ops). So DMA API can go with the direct mapping then the vringh will > > be happy since mlx5_vdpa assuems a direct/identical mapping by > > default. > > > > Could you provide instructions how to reproduce the crash you were seeing? It should be something like: 1) boot host kernel with iommu enabled but not in passthrough mode: I use intel_iommu=on 2) create vdpa device on top of mlx5_vdpa VF 3) bind the vdpa device to virtio_vdpa Then I can see the crash. Thanks > > > Please review. > > > > Thanks > > > > Jason Wang (5): > > virtio_ring: per virtqueue dma device > > vdpa: introduce get_vq_dma_device() > > virtio-vdpa: support per vq dma device > > vdpa: set dma mask for vDPA device > > vdpa: mlx5: support per virtqueue dma device > > > > drivers/vdpa/mlx5/net/mlx5_vnet.c | 11 +++ > > drivers/vdpa/vdpa.c | 5 ++ > > drivers/virtio/virtio_ring.c | 133 +++++++++++++++++++++--------- > > drivers/virtio/virtio_vdpa.c | 13 ++- > > include/linux/vdpa.h | 6 ++ > > include/linux/virtio_ring.h | 16 ++++ > > 6 files changed, 141 insertions(+), 43 deletions(-) > > > > -- > > 2.25.1 > _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
