Re: [virtio-comment] About adding a new device type virtio-nvme

[Max Gurtovoy <mgurtovoy@nvidia.com>]

On 17/01/2023 4:04, 侯英乐 wrote:
> On Wed, 11 Jan 2023 10:16:55 -0500, Stefan wrote:
>
>
>>> On Wed, Jan 11, 2023 at 11:21:35AM +0800, 侯英乐 wrote:
>>> As we know, nvme has more features than virtio-blk. For example, with the development of virtualization IO offloading to hardware, virtio-blk and NVME-OF offloading to hardware >are developing rapidly.  So if virtio and nvme are combined into Virtio-NvMe, Is it necessary to add a device type Virtio-NvMe ?
>
>
>   
>
>
>
>> Hi,
>> In theory, yes, virtio-nvme can be done. The question is why do it?
>
>
>> NVMe already provides a PCI hardware spec for software and hardware
>> implementations to follow. An NVMe PCI device can be exposed to the
>> guest and modern operating systems recognize it without requiring new
>> drivers.
>
>> The value of VIRTIO here is probably in the deep integration into the
>> virtualization stack with vDPA, vhost, etc. A virtio-nvme device can use
>> all these things whereas a PCI device needs to do everything from
>> scratch.
>
> The NVME technology and ecosystem are complete. However, in virtualization scenarios, NVME devices can only use PCIe pass-through . When NVME and virtio combine to connect to the vDPA ecosystem, live migration is supported.
>
>
>> Let's not forget that virtio-blk is widely used and new commands are
>> being added as needed. Which NVMe features are you missing in
>> virtio-blk?
> With the introduction of the concept of DPU, a large number of vendors are offloading virtual devices to hardware. The back-end of Virtio-blk does not support remote storage. Therefore, Virtio-Nvme-of can well combine the advantages of remote storage and virtio live migration
>
>
>
>> I guess this is why virtio-nvme hasn't been done before: people who want
>> NVMe can already do NVMe PCI, people who want VIRTIO can use virtio-blk,
>> and so there hasn't been a great need to combine VIRTIO and NVMe yet.
>
>> What advantages do you see in having virtio-nvme?
>
>
> virtio-nvme advantages :
> 1)  live migration

This is WIP and will use VFIO live migration framework.

> 2)  support remote storage

There are solutions today that can use remote storage as an NVMe 
Namespace. For example, DPU based NVMe device such as NVIDIA'S NVMe SNAP 
device.

>
>
>
> Leo Hou/侯英乐
>

This publicly archived list offers a means to provide input to the
OASIS Virtual I/O Device (VIRTIO) TC.

In order to verify user consent to the Feedback License terms and
to minimize spam in the list archive, subscription is required
before posting.

Subscribe: virtio-comment-subscribe@lists.oasis-open.org
Unsubscribe: virtio-comment-unsubscribe@lists.oasis-open.org
List help: virtio-comment-help@lists.oasis-open.org
List archive: https://lists.oasis-open.org/archives/virtio-comment/
Feedback License: https://www.oasis-open.org/who/ipr/feedback_license.pdf
List Guidelines: https://www.oasis-open.org/policies-guidelines/mailing-lists
Committee: https://www.oasis-open.org/committees/virtio/
Join OASIS: https://www.oasis-open.org/join/