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

[Si-Wei Liu]

On 9/13/2023 9:08 AM, Eugenio Perez Martin wrote:
> On Wed, Sep 13, 2023 at 3:03 AM Lei Yang <leiyang@xxxxxxxxxx> wrote:
> > Hi Dragos, Eugenio and Si-Wei
> >
> > My name is Lei Yang, a software Quality Engineer from Red Hat.  And
> > always paying attention to improving the live migration downtime
> > issues because there are others QE asked about this problem when I
> > share live migration status  recently. Therefore I would like to test
> > it in my environment. Before the testing I want to know if there is an
> > expectation of downtime range based on this series of patches? In
> > addition, QE also can help do a regression test based on this series
> > of patches if there is a requirement.
> Hi Lei,
>
> Thanks for offering the testing bandwidth!
>
> I think we can only do regression tests here, as the userland part is
> still not sent to qemu.
Right. Regression for now, even QEMU has it, to exercise the relevant 
feature it would need a supporting firmware that is not yet available 
for now. Just stay tuned.

thanks for your patience,
-Siwei
> > Regards and thanks
> > Lei
> >
> >
> > On Tue, Sep 12, 2023 at 9:04 PM Dragos Tatulea <dtatulea@xxxxxxxxxx> 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.
> > >
> > > [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(-)
> > >
> > > --
> > > 2.41.0