lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Wed, 13 May 2020 10:29:31 +0800
From:   Jason Wang <>
To:     Jason Gunthorpe <>,
        "Raj, Ashok" <>
Cc:     "Tian, Kevin" <>,
        Alex Williamson <>,
        "Jiang, Dave" <>,
        "" <>,
        "" <>,
        "" <>,
        "" <>,
        "" <>,
        "" <>,
        "" <>,
        "" <>,
        "Pan, Jacob jun" <>,
        "Liu, Yi L" <>, "Lu, Baolu" <>,
        "Kumar, Sanjay K" <>,
        "Luck, Tony" <>,
        "Lin, Jing" <>,
        "Williams, Dan J" <>,
        "" <>,
        "" <>,
        "" <>,
        "" <>,
        "" <>,
        "" <>,
        "" <>,
        "" <>,
        Paolo Bonzini <>
Subject: Re: [PATCH RFC 00/15] Add VFIO mediated device support and IMS
 support for the idxd driver.

On 2020/5/9 下午8:21, Jason Gunthorpe wrote:
> On Fri, May 08, 2020 at 05:09:09PM -0700, Raj, Ashok wrote:
>> Hi Jason
>> On Fri, May 08, 2020 at 08:16:10PM -0300, Jason Gunthorpe wrote:
>>> On Fri, May 08, 2020 at 01:47:10PM -0700, Raj, Ashok wrote:
>>>> Even when uaccel was under development, one of the options
>>>> was to use VFIO as the transport, goal was the same i.e to keep
>>>> the user space have one interface.
>>> I feel a bit out of the loop here, uaccel isn't in today's kernel is
>>> it? I've heard about it for a while, it sounds very similar to RDMA,
>>> so I hope they took some of my advice...
>> I think since 5.7 maybe? drivers/misc/uacce. I don't think this is like
>> RDMA, its just a plain accelerator. There is no connection management,
>> memory registration or other things.. IB was my first job at Intel,
>> but saying that i would be giving my age away:)
> rdma was the first thing to do kernel bypass, all this stuff is like
> rdma at some level.. I see this looks like the 'warp driver' stuff
> redone
> Wow, lots wrong here. Oh well.
>>> putting emulation code back into them, except in a more dangerous
>>> kernel location. This does not seem like a net win to me.
>> Its not a whole lot of emulation right? mdev are soft partitioned. There is
>> just a single PF, but we can create a separate partition for the guest using
>> PASID along with the normal BDF (RID). And exposing a consistent PCI like
>> interface to user space you get everything else for free.
>> Yes, its not SRIOV, but giving that interface to user space via VFIO, we get
>> all of that functionality without having to reinvent a different way to do it.
>> vDPA went the other way, IRC, they went and put a HW implementation of what
>> virtio is in hardware. So they sort of fit the model. Here the instance
>> looks and feels like real hardware for the setup and control aspect.
> VDPA and this are very similar, of course it depends on the exact HW
> implementation.
> Jason

Actually this is not a must. Technically we can do ring/descriptor 
translation in the vDPA driver as what zerocopy AF_XDP did.



Powered by blists - more mailing lists