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List:       linux-rdma
Subject:    Re: mlx4 query in sriov mode
From:       Bob Biloxi <iambobbiloxi () gmail ! com>
Date:       2014-08-29 9:19:01
Message-ID: CANwwZzVbx5TdFwK=8-FOHzT4FVyk6ZX+2P2kNmW0MkSDzyOSug () mail ! gmail ! com
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Hi,

> Where you fund the communication between PF and VF is by writing its BAR?
http://lxr.free-electrons.com/source/drivers/net/ethernet/mellanox/mlx4/cmd.c#L1964


Best Regards,
Bob

On Fri, Aug 29, 2014 at 9:51 AM, Wei Yang <weiyang@linux.vnet.ibm.com> wrote:
> On Thu, Aug 28, 2014 at 10:58:50PM +0530, Bob Biloxi wrote:
>>Hi All,
>>
>>
>>I really appreciate this wonderful community which has immensely
>>helped me broaden my knowledge and understanding.
>>
>>
>>I was going through the mlx4 sriov code, trying to understand the
>>communication between the VF driver and the PF driver.
>>
>>I was having a few queries..hoping to get a better understanding.
>>
>>
>>As I understand, the commands are communicated between VF and PF
>>through a mechanism called communication channel. VF writes to
>>specific address in its BAR space, PF gets an event and then proceeds
>>ahead to read the command from its BAR space and then complete the
>>execution of it..
>>
>>
>>Now, my query is, lets say the VF driver is not yet present and only
>>the PF driver is there...
>>
>>In this case, can we simulate a VF command write and get notified
>>through an event?
>>
>
> Hi,
>
> I am not that familiar with mlx4 driver. As you mentioned in previous, VF
> communicate with PF by writing some word in BAR and PF gets it. If this is
> true, I believe it would works.
>
>>For eg. we write to some offset in the PF BAR space itself upon
>>completion of which, an event is generated because of the write? kind
>>of like loopback mechanism.
>>
>>
>>I searched through the code but couldn't find anywhere.
>>
>>Can anyone please help me understand if this is possible? And if there
>>is any location in the code where i can find this?
>
> Where you fund the communication between PF and VF is by writing its BAR?
>
>>
>>Thanks a lot in advance!!
>>
>>
>>Best Regards,
>>Bob
>>--
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>
> --
> Richard Yang
> Help you, Help me
>
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