Subject: Re: [PATCH 3/5] vDPA: introduce vDPA bus

From: "Michael S. Tsirkin" <[email-masked]>
Date: Mon, 20 Jan 2020 07:09:07 -0500

On Mon, Jan 20, 2020 at 04:44:34PM +0800, Jason Wang wrote:
> 
> On 2020/1/19 下午5:59, Michael S. Tsirkin wrote:
> > On Sun, Jan 19, 2020 at 09:07:09AM +0000, Shahaf Shuler wrote:
> > > > Technically, we can keep the incremental API
> > > > here and let the vendor vDPA drivers to record the full mapping
> > > > internally which may slightly increase the complexity of vendor driver.
> > > What will be the trigger for the driver to know it received the last mapping on this series and it can now push it to the on-chip IOMMU?
> > Some kind of invalidate API?
> > 
> 
> The problem is how to deal with the case of vIOMMU. When vIOMMU is enabling
> there's no concept of last mapping.
> 
> Thanks

Most IOMMUs have a translation cache so have an invalidate API too.

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MST