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

[Dragos Tatulea]

On Tue, 2023-09-26 at 05:22 -0700, Si-Wei Liu wrote:
> 
> 
> On 9/25/2023 12:59 AM, Dragos Tatulea wrote:
> > On Tue, 2023-09-12 at 16:01 +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.
> > > 
> > Gentle ping.
> > 
> > Note that I will have to send a v2. The changes in mlx5_ifc.h will need to
> > be
> > merged first separately into the mlx5-next branch [0] and then pulled from
> > there
> > when the series is applied.
> This separation is unnecessary, as historically the virtio emulation 
> portion of the update to mlx5_ifc.h often had to go through the vhost 
> tree. See commits 1892a3d425bf and e13cd45d352d. Especially the 
> additions from this series (mainly desc group mkey) have nothing to do 
> with any networking or NIC driver feature.
> 
The reason for doing that is to avoid conflicts in Linus's tree on the
mlx5_ifc.h file.

Thanks,
Dragos

> -Siwei
> 
> > 
> > [0]
> > https://git.kernel.org/pub/scm/linux/kernel/git/mellanox/linux.git/log/?h=mlx5-next
> > 
> > Thanks,
> > Dragos
> > 
> > > 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.
> > > 
> > > [0]
> > > https://lore.kernel.org/virtualization/1694248959-13369-1-git-send-email-si-wei.liu@xxxxxxxxxx
> > > 
> > > Dragos Tatulea (13):
> > >    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
> > >    Cover letter: vdpa/mlx5: Add support for vq descriptor mappings
> > > 
> > > 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(-)
> > > 
>