Re: [PATCH for-next v2] RDMA/efa: Add EFA query MR support

["Margolin, Michael" <mrgolin@amazon.com>]

On 12/11/2023 10:10 AM, Leon Romanovsky wrote:
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>
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> On Thu, Dec 07, 2023 at 02:27:48PM +0000, Michael Margolin wrote:
>> Add EFA driver uapi definitions and register a new query MR method that
>> currently returns the physical PCI buses' IDs the device is using to
>> reach the MR. Update admin definitions and efa-abi accordingly.
>>
>> Reviewed-by: Anas Mousa <anasmous@amazon.com>
>> Reviewed-by: Firas Jahjah <firasj@amazon.com>
>> Signed-off-by: Michael Margolin <mrgolin@amazon.com>
>> ---
>>  drivers/infiniband/hw/efa/efa.h               |  5 +-
>>  .../infiniband/hw/efa/efa_admin_cmds_defs.h   | 31 ++++++++
>>  drivers/infiniband/hw/efa/efa_com_cmd.c       |  6 ++
>>  drivers/infiniband/hw/efa/efa_com_cmd.h       |  4 +
>>  drivers/infiniband/hw/efa/efa_main.c          |  5 ++
>>  drivers/infiniband/hw/efa/efa_verbs.c         | 77 +++++++++++++++++++
>>  include/uapi/rdma/efa-abi.h                   | 19 +++++
>>  7 files changed, 146 insertions(+), 1 deletion(-)
> <...>
>
>> +     /*
>> +      * Mask indicating which fields have valid values
>> +      * 0 : recv_pci_bus_id
>> +      * 1 : rdma_read_pci_bus_id
>> +      * 2 : rdma_recv_pci_bus_id
>> +      */
>> +     u8 validity;
> <...>
>
>>  #define EFA_GID_SIZE 16
>> +#define EFA_INVALID_PCI_BUS_ID 0xffff
> Is 0xffff value guaranteed by PCI subsystem to be invalid? Why don't you
> provide "validity" field to userspace instead?

The 0xffff value in only used internally in the driver to indicate an
invalid id and isn't exposed to userspace. For userspace there is a
validity field as you suggested:

+       return uverbs_copy_to(attrs,
EFA_IB_ATTR_QUERY_MR_RESP_PCI_BUS_ID_VALIDITY,
+                             &pci_bus_id_validity,
sizeof(pci_bus_id_validity));


Thanks