[PATCH vhost v1 00/19] virtio: drivers maintain dma info for premapped vq

[Michael S. Tsirkin]

On Fri, Feb 02, 2024 at 05:39:32PM +0800, Xuan Zhuo wrote:
> As discussed:
> http://lore.kernel.org/all/CACGkMEvq0No8QGC46U4mGsMtuD44fD_cfLcPaVmJ3rHYqRZxYg@mail.gmail.com
> 
> If the virtio is premapped mode, the driver should manage the dma info by self.
> So the virtio core should not store the dma info.
> So we can release the memory used to store the dma info.
> 
> But if the desc_extra has not dma info, we face a new question,
> it is hard to get the dma info of the desc with indirect flag.
> For split mode, that is easy from desc, but for the packed mode,
> it is hard to get the dma info from the desc. And for hardening
> the dma unmap is saft, we should store the dma info of indirect
> descs.
> 
> So I introduce the "structure the indirect desc table" to
> allocate space to store dma info with the desc table.
> 
> On the other side, we mix the descs with indirect flag
> with other descs together to share the unmap api. That
> is complex. I found if we we distinguish the descs with
> VRING_DESC_F_INDIRECT before unmap, thing will be clearer.
> 
> Because of the dma array is allocated in the find_vqs(),
> so I introduce a new parameter to find_vqs().
> 
> Please review.
> 
> Thanks

this needs a rebase - conflicts with e.g.
commit e3fe8d28c67bf6c291e920c6d04fa22afa14e6e4
Author: Zhu Yanjun <yanjun.zhu at linux.dev>
Date:   Thu Jan 4 10:09:02 2024 +0800

    virtio_net: Fix "‘%d’ directive writing between 1 and 11 bytes into a region of size 10" warnings
    
    Fix the warnings when building virtio_net driver.
    

thanks!


> v1:
>     1. rename transport_vq_config to vq_transport_config
>     2. virtio-net set dma meta number to (ring-size + 1)(MAX_SKB_FRGAS +2)
>     3. introduce virtqueue_dma_map_sg_attrs
>     4. separate vring_create_virtqueue to an independent commit
> 
> Xuan Zhuo (19):
>   virtio_ring: introduce vring_need_unmap_buffer
>   virtio_ring: packed: remove double check of the unmap ops
>   virtio_ring: packed: structure the indirect desc table
>   virtio_ring: split: remove double check of the unmap ops
>   virtio_ring: split: structure the indirect desc table
>   virtio_ring: no store dma info when unmap is not needed
>   virtio: find_vqs: pass struct instead of multi parameters
>   virtio: vring_create_virtqueue: pass struct instead of multi
>     parameters
>   virtio: vring_new_virtqueue(): pass struct instead of multi parameters
>   virtio_ring: reuse the parameter struct of find_vqs()
>   virtio: find_vqs: add new parameter premapped
>   virtio_ring: export premapped to driver by struct virtqueue
>   virtio_net: set premapped mode by find_vqs()
>   virtio_ring: remove api of setting vq premapped
>   virtio_ring: introduce dma map api for page
>   virtio_ring: introduce virtqueue_dma_map_sg_attrs
>   virtio_net: unify the code for recycling the xmit ptr
>   virtio_net: rename free_old_xmit_skbs to free_old_xmit
>   virtio_net: sq support premapped mode
> 
>  arch/um/drivers/virtio_uml.c             |  31 +-
>  drivers/net/virtio_net.c                 | 291 +++++++---
>  drivers/platform/mellanox/mlxbf-tmfifo.c |  24 +-
>  drivers/remoteproc/remoteproc_virtio.c   |  31 +-
>  drivers/s390/virtio/virtio_ccw.c         |  33 +-
>  drivers/virtio/virtio_mmio.c             |  30 +-
>  drivers/virtio/virtio_pci_common.c       |  59 +-
>  drivers/virtio/virtio_pci_common.h       |   9 +-
>  drivers/virtio/virtio_pci_legacy.c       |  16 +-
>  drivers/virtio/virtio_pci_modern.c       |  24 +-
>  drivers/virtio/virtio_ring.c             | 698 ++++++++++++-----------
>  drivers/virtio/virtio_vdpa.c             |  45 +-
>  include/linux/virtio.h                   |  13 +-
>  include/linux/virtio_config.h            |  48 +-
>  include/linux/virtio_ring.h              |  82 +--
>  tools/virtio/virtio_test.c               |   4 +-
>  tools/virtio/vringh_test.c               |  28 +-
>  17 files changed, 848 insertions(+), 618 deletions(-)
> 
> --
> 2.32.0.3.g01195cf9f