On Tue, Mar 10, 2026 at 12:57:30PM -0700, Nicolin Chen wrote:

On Tue, Mar 10, 2026 at 07:40:56PM +0000, Pranjal Shrivastava wrote:

quoted

On Fri, Mar 06, 2026 at 09:02:02AM -0400, Jason Gunthorpe wrote:

quoted

On Thu, Mar 05, 2026 at 09:06:17PM -0800, Nicolin Chen wrote:

quoted

On Thu, Mar 05, 2026 at 09:33:47PM -0400, Jason Gunthorpe wrote:

quoted

On Thu, Mar 05, 2026 at 05:29:22PM -0800, Nicolin Chen wrote:

quoted

But arm_smmu_cmdq_issue_cmdlist() doesn't know when to push another
CMD. In my case where ATC_INV irq occurs, the return value from the
arm_smmu_cmdq_poll_until_sync() in the Step 5 is 0, and prods/cons
are also matched. Actually, at this point that NOP ISR has already
finished.

Yes, you'd need a sneaky way to convay the error from the ISR to the
cmdlist code that didn't harm performance. Maybe we could come up with
something, but if it works replacing the NOP with flush sounds fairly
appealing - though can you do a single WORD edit to the STE that will
block translated requests? Zero EATS?

Yea. I can give that a try.

This also really needs to go after the invalidation changes because it
is feasible to also edit the lockless RCU invalidation list from the
ISR and disable the ATC for the failed device too.

quoted

quoted

Also, will the SMMU start spamming with blocked translation events or
something that will need suppression too?

CD.R=0 can suppress fault records, but we would need to override
that in every CD of the device.

That's too much to do from ISR, but maybe we can do it from a WQ..

(Skimming through these, apologies if I'm losing context), shouldn't we
do all that (marking it as an inv STE / abort STE, suppressing the
faults) in the worker instead of trying to reset/recover the device?

EATS should be unset asap to avoid memory corruption. It's best
to do in the unmap() context where the page isn't reclaimed yet
by the kernel.

Makes sense.

Worker thread will be a bit late, but it is good enough for any
further step.

Ack.
Praan