Re: [PATCH vhost v2 00/16] vdpa: Add support for vq descriptor mappings

[Dragos Tatulea <dtatulea@nvidia.com>]

On Thu, 2023-10-05 at 13:31 -0400, Michael S. Tsirkin wrote:
> On Thu, Sep 28, 2023 at 07:45:11PM +0300, Dragos Tatulea wrote:
> > This patch series adds support for vq descriptor table mappings which
> > are used to improve vdpa live migration downtime. The improvement comes
> > from using smaller mappings which take less time to create and destroy
> > in hw.
> > 
> > The first part adds the vdpa core changes from Si-Wei [0].
> > 
> > The second part adds support in mlx5_vdpa:
> > - Refactor the mr code to be able to cleanly add descriptor mappings.
> > - Add hardware descriptor mr support.
> > - Properly update iotlb for cvq during ASID switch.
> > 
> > Changes in v2:
> > 
> > - The "vdpa/mlx5: Enable hw support for vq descriptor mapping" change
> >   was split off into two patches to avoid merge conflicts into the tree
> >   of Linus.
> > 
> >   The first patch contains only changes for mlx5_ifc.h. This must be
> >   applied into the mlx5-next tree [1] first. Once this patch is applied
> >   on mlx5-next, the change has to be pulled fom mlx5-next into the vhost
> >   tree and only then the remaining patches can be applied.
> 
> 
> I get it you plan v3?
There are some very small improvements (commit message in 13/16 and fix in
16/16) that could make a v3. The latter can be addressed as a separate patch
when moving dup_iotlb to vhost/iotlb. What do you think?

> 
> > [0]
> > https://lore.kernel.org/virtualization/1694248959-13369-1-git-send-email-si-wei.liu@oracle.com
> > [1]
> > https://git.kernel.org/pub/scm/linux/kernel/git/mellanox/linux.git/log/?h=mlx5-next
> > 
> > Dragos Tatulea (13):
> >   vdpa/mlx5: Expose descriptor group mkey hw capability
> >   vdpa/mlx5: Create helper function for dma mappings
> >   vdpa/mlx5: Decouple cvq iotlb handling from hw mapping code
> >   vdpa/mlx5: Take cvq iotlb lock during refresh
> >   vdpa/mlx5: Collapse "dvq" mr add/delete functions
> >   vdpa/mlx5: Rename mr destroy functions
> >   vdpa/mlx5: Allow creation/deletion of any given mr struct
> >   vdpa/mlx5: Move mr mutex out of mr struct
> >   vdpa/mlx5: Improve mr update flow
> >   vdpa/mlx5: Introduce mr for vq descriptor
> >   vdpa/mlx5: Enable hw support for vq descriptor mapping
> >   vdpa/mlx5: Make iotlb helper functions more generic
> >   vdpa/mlx5: Update cvq iotlb mapping on ASID change
> > 
> > Si-Wei Liu (3):
> >   vdpa: introduce dedicated descriptor group for virtqueue
> >   vhost-vdpa: introduce descriptor group backend feature
> >   vhost-vdpa: uAPI to get dedicated descriptor group id
> > 
> >  drivers/vdpa/mlx5/core/mlx5_vdpa.h |  31 +++--
> >  drivers/vdpa/mlx5/core/mr.c        | 191 ++++++++++++++++-------------
> >  drivers/vdpa/mlx5/core/resources.c |   6 +-
> >  drivers/vdpa/mlx5/net/mlx5_vnet.c  | 100 ++++++++++-----
> >  drivers/vhost/vdpa.c               |  27 ++++
> >  include/linux/mlx5/mlx5_ifc.h      |   8 +-
> >  include/linux/mlx5/mlx5_ifc_vdpa.h |   7 +-
> >  include/linux/vdpa.h               |  11 ++
> >  include/uapi/linux/vhost.h         |   8 ++
> >  include/uapi/linux/vhost_types.h   |   5 +
> >  10 files changed, 264 insertions(+), 130 deletions(-)
> > 
> > -- 
> > 2.41.0
>