Re: [PATCH v13 07/13] iommu/vt-d: Add SVA domain support

[Jason Gunthorpe]

On Fri, Sep 23, 2022 at 08:41:56PM +0800, Baolu Lu wrote:
> On 2022/9/23 20:15, Jason Gunthorpe wrote:
> > On Fri, Sep 23, 2022 at 10:21:51AM +0800, Baolu Lu wrote:
> > 
> > > At the beginning of this project, I wanted to consolidate the mm
> > > notifications into the core. However, ARM SMMUv3 and Intel handle the mm
> > > notifications a little differently. Then I decided to do this work
> > > separately from the current series.
> > 
> > It doesn't look really different..
> 
> They are essentially the same, but slightly different. For example, arm
> smmuv3 provides .free_notifier, and I don't think it could be merged to
> the release callback.

free_notifier allows to use mmu_notifier_put() instead of
mmu_notifier_unregister() which avoids a synchronize_rcu() penalty on
teardown. Intel should copy the same design.

Jason