Re: [PATCH 0/2] Introduce iommu_commit() function

Joerg Roedel
2011-06-29T05:51:09Z

On Wed, Jun 29, 2011 at 02:02:02PM +0900, KyongHo Cho wrote:
> Hi.
>
> On Fri, Jun 24, 2011 at 12:31 AM, Joerg Roedel <joerg.roedel@amd.com> wrote:
> > It needs to be called whenever a some code changed a domain (either by
> > attaching/detaching devices or by mapping/unmapping pages in
> > the domain).
>
> Do you mean we can invalidate IOTLB with this iommu_commit()?
> We need to invalidate IOTLB without updating page table for some
> optimized solutions.
>
> If a device in one domain is moved to other domain, IOTLB of the
> device must be invalidated
> because it contains translation information of the previous domain.

The classic use-case is to do a single iommu-tlb flush after a set of
page-table updates, but flushing iotlbs after moving devices is a
potential use-case too, so the answer is yes.

Regards,

Joerg