Re: [PATCH v3 03/13] iommu/arm-smmu-v3: Drain in-flight fault events on domain detach

[Jason Gunthorpe]

On Fri, Sep 04, 2026 at 03:57:14PM -0700, Nicolin Chen wrote:
> On Fri, Sep 04, 2026 at 11:09:06AM -0300, Jason Gunthorpe wrote:
> > On Thu, Sep 03, 2026 at 12:18:33PM -0700, Jonathan Cameron wrote:
> > > > Also run the drain for every stall-capable master, even when the departing
> > > > attachment did not enable IOPF: such a stall event has to be aborted while
> > > > it still resolves to the old attach handle, 
> > 
> > That isn't the model for fault handling. The fault is delivered
> > unpredictably into either old or new domain. It doesn't matter which
> > one.
> > 
> > Domains have to conclude their fault proceessing before they are
> > destroyed, and attach to the a non-fault domain has to conclude faults
> > before completing the attach.
> > 
> > But there is no requirement to deliver faults to any particular thing.
> 
> Edited:
> 
> Also run the drain for every stall-capable master, even when the departing
> attachment did not enable IOPF. An attachment has to conclude its in-flight
> faults before the attach completes, as the incoming domain might not handle
> a fault at all.

I still don't understand from this why an non-fault capable domain
would need to flush on becoming replaced?

Jason