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Subject: Re: [PATCH] vhost: introduce vDPA based backend
To:     Tiwei Bie <tiwei.bie@intel.com>
Cc:     "Michael S. Tsirkin" <mst@redhat.com>,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
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        maxime.coquelin@redhat.com, lingshan.zhu@intel.com,
        dan.daly@intel.com, cunming.liang@intel.com, zhihong.wang@intel.com
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From:   Jason Wang <jasowang@redhat.com>
Message-ID: <798e5644-ca28-ee46-c953-688af9bccd3b@redhat.com>
Date:   Wed, 5 Feb 2020 11:12:21 +0800
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On 2020/2/5 =E4=B8=8A=E5=8D=8810:05, Tiwei Bie wrote:
> On Tue, Feb 04, 2020 at 02:46:16PM +0800, Jason Wang wrote:
>> On 2020/2/4 =E4=B8=8B=E5=8D=882:01, Michael S. Tsirkin wrote:
>>> On Tue, Feb 04, 2020 at 11:30:11AM +0800, Jason Wang wrote:
>>>> 5) generate diffs of memory table and using IOMMU API to setup the d=
ma
>>>> mapping in this method
>>> Frankly I think that's a bunch of work. Why not a MAP/UNMAP interface=
?
>>>
>> Sure, so that basically VHOST_IOTLB_UPDATE/INVALIDATE I think?
> Do you mean we let userspace to only use VHOST_IOTLB_UPDATE/INVALIDATE
> to do the DMA mapping in vhost-vdpa case? When vIOMMU isn't available,
> userspace will set msg->iova to GPA, otherwise userspace will set
> msg->iova to GIOVA, and vhost-vdpa module will get HPA from msg->uaddr?
>
> Thanks,
> Tiwei


I think so. Michael, do you think this makes sense?

Thanks


>
>> Thanks
>>
>>