Re: [PATCH v4 12/18] iommu/vt-d: Handle reattach of the restored domain

[Jason Gunthorpe]

On Fri, Sep 18, 2026 at 02:59:43AM +0000, Samiullah Khawaja wrote:
> On Fri, Aug 28, 2026 at 04:15:56PM +0000, Samiullah Khawaja wrote:
> > On Fri, Aug 28, 2026 at 11:35:46AM -0300, Jason Gunthorpe wrote:
> > > On Fri, Aug 28, 2026 at 09:55:18AM +0800, Baolu Lu wrote:
> > > > That looks reasonable to me. I have no concerns about keeping ATS
> > > > enabled on preserved devices across kexec reboot, as long as the
> > > > software state is synchronized in the new kernel.
> > > 
> > > The new kernel should issue an ATC flush when it changes away from the
> > > inherented domain.
> > 
> > Yes, I will make sure this happens when we do the retrieval side. It
> > should mostly work well with the existing replace machinery.
> > > 
> > > > By the way, is disabling ATS an option?
> > > 
> > > No, many devices require ATS.
> > 
> > Agreed on the ATS requirement. I had Nicolin's patch series for CXL
> > devices in mind here.
> 
> Having implemented this now, I am thinking about this again with respect
> to the scope of this series. To limit the scope of this series I am
> going to refuse preservation of devices that have ATS enabled. Once the
> base preservation logic goes in, I can add a separate series on top of
> it to add that support.

That seems reasonable

Jason