From: Zhu Lingshan <lingshan.zhu@linux.intel.com>
To: Jason Wang <jasowang@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Jason Gunthorpe <jgg@mellanox.com>
Cc: Shahaf Shuler <shahafs@mellanox.com>,
Tiwei Bie <tiwei.bie@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"rob.miller@broadcom.com" <rob.miller@broadcom.com>,
"haotian.wang@sifive.com" <haotian.wang@sifive.com>,
"eperezma@redhat.com" <eperezma@redhat.com>,
"lulu@redhat.com" <lulu@redhat.com>,
Parav Pandit <parav@mellanox.com>,
"rdunlap@infradead.org" <rdunlap@infradead.org>,
"hch@infradead.org" <hch@infradead.org>,
Jiri Pirko <jiri@mellanox.com>,
"hanand@xilinx.com" <hanand@xilinx.com>,
"mhabets@solarflare.com" <mhabets@solarflare.com>,
"maxime.coquelin@redhat.com" <maxime.coquelin@redhat.com>,
"lingshan.zhu@intel.com" <lingshan.zhu@intel.com>,
"dan.daly@intel.com" <dan.daly@intel.com>,
"cunming.liang@intel.com" <cunming.liang@intel.com>,
"zhihong.wang@intel.com" <zhihong.wang@intel.com>
Subject: Re: [PATCH] vhost: introduce vDPA based backend
Date: Thu, 6 Feb 2020 11:21:27 +0800 [thread overview]
Message-ID: <4b1753eb-b281-17e0-6636-849ac20cbe50@linux.intel.com> (raw)
In-Reply-To: <55b050d6-b31d-f8a2-2a15-0fc68896d47f@redhat.com>
On 2/6/2020 11:11 AM, Jason Wang wrote:
>
> On 2020/2/5 下午9:14, Michael S. Tsirkin wrote:
>> On Wed, Feb 05, 2020 at 08:56:48AM -0400, Jason Gunthorpe wrote:
>>> On Wed, Feb 05, 2020 at 03:50:14PM +0800, Jason Wang wrote:
>>>>> Would it be better for the map/umnap logic to happen inside each
>>>>> device ?
>>>>> Devices that needs the IOMMU will call iommu APIs from inside the
>>>>> driver callback.
>>>> Technically, this can work. But if it can be done by vhost-vpda it
>>>> will make
>>>> the vDPA driver more compact and easier to be implemented.
>>> Generally speaking, in the kernel, it is normal to not hoist code of
>>> out drivers into subsystems until 2-3 drivers are duplicating that
>>> code. It helps ensure the right design is used
>>>
>>> Jason
>> That's up to the sybsystem maintainer really, as there's also some
>> intuition involved in guessing a specific API is widely useful.
>> In-kernel APIs are flexible, if we find something isn't needed we just
>> drop it.
>>
>
> If I understand correctly. At least Intel (Ling Shan) and Brodcom
> (Rob) doesn't want to deal with DMA stuffs in their driver.
>
> Anyway since the DMA bus operations is optional, driver may still
> choose to do DMA by itself if they want even if it requires platform
> IOMMU to work.
>
> Thanks
>
Many Thanks if this could be done. The parent device has DMA
capabilities and dma ops implemented, we hope can make use of it, as
discussed in the vdpa thread.
next prev parent reply other threads:[~2020-02-06 3:21 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-31 3:36 [PATCH] vhost: introduce vDPA based backend Tiwei Bie
2020-01-31 3:56 ` Randy Dunlap
2020-01-31 5:12 ` Randy Dunlap
2020-01-31 5:54 ` Tiwei Bie
2020-01-31 5:52 ` Tiwei Bie
2020-02-04 3:30 ` Jason Wang
2020-02-04 6:01 ` Michael S. Tsirkin
2020-02-04 6:46 ` Jason Wang
2020-02-05 2:05 ` Tiwei Bie
2020-02-05 3:12 ` Jason Wang
2020-02-05 5:31 ` Michael S. Tsirkin
2020-02-05 5:50 ` Jason Wang
2020-02-05 6:30 ` Michael S. Tsirkin
2020-02-05 6:49 ` Jason Wang
2020-02-05 7:16 ` Michael S. Tsirkin
2020-02-05 7:42 ` Jason Wang
2020-02-05 9:22 ` Michael S. Tsirkin
2020-02-05 2:02 ` Tiwei Bie
2020-02-05 3:11 ` Jason Wang
2020-02-05 7:15 ` Shahaf Shuler
2020-02-05 7:50 ` Jason Wang
2020-02-05 9:23 ` Michael S. Tsirkin
2020-02-06 3:07 ` Jason Wang
2020-02-05 9:30 ` Shahaf Shuler
2020-02-05 10:33 ` Michael S. Tsirkin
2020-02-06 3:09 ` Jason Wang
2020-02-06 3:04 ` Jason Wang
2020-02-05 12:56 ` Jason Gunthorpe
2020-02-05 13:14 ` Michael S. Tsirkin
2020-02-06 3:11 ` Jason Wang
2020-02-06 3:21 ` Zhu Lingshan [this message]
2020-02-18 13:53 ` Jason Gunthorpe
2020-02-19 2:52 ` Tiwei Bie
2020-02-19 13:11 ` Jason Gunthorpe
2020-02-20 2:42 ` Tiwei Bie
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