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

[Si-Wei Liu <si-wei.liu@oracle.com>]

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.

-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@oracle.com
>>
>> 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(-)
>>