Re: [PATCH v9 01/12] iommu/arm-smmu-v3: Refactor arm_smmu_setup_irqs
From: Pranjal Shrivastava <praan@google.com>
Date: 2026-08-25 19:01:46
Also in:
linux-iommu
On Tue, Aug 25, 2026 at 11:47:57AM -0700, Nicolin Chen wrote:
On Tue, Aug 25, 2026 at 05:35:28PM +0000, Pranjal Shrivastava wrote:quoted
On Tue, Aug 25, 2026 at 01:36:11PM -0300, Jason Gunthorpe wrote:quoted
quoted
[ ... 84 lines skipped ... ] + /* Setup interrupt handlers */ + ret = arm_smmu_setup_irqs(smmu); + if (ret) { + dev_err(smmu->dev, "failed to setup irqs\n"); + return ret; + } +The sashiko remark makes sense to me, we should not enable interrupts until everything has been initialized and things are ready to go. So this is better done after the device reset call, which is the thing that is setting up the queue pointers in HW.. I'm not sure what to make of the MSI register ordering around kdump comment.. Nicolin?Ack. I agree with Sashiko's remarks, we'd need to call this within device_reset right before the SMMU is enabled (same place as today). I factored this out to avoid setting up irq handlers multiple times across a suspend / resume cycle (for e.g. we can't request_irq multiple times for the same irq). Otherwise, we'd have to de-register IRQ handlers in the suspend callback. Maybe we could do this ONCE based on some smmu->inited bool?Yea, setting MSI while IRQ and CMDQ are enabled might be an issue. FWIW, my kdump series disables EVTQ and PRIQ, so the concern would only apply to GERROR.
Hmm, I guess I'll move it into the reset handler with some smmu->inited? The other thing could be somehow masking all interrupts till we *really* enable the SMMU. Which one sounds better to you? Any preference? (Will / Jason / Mostafa / Daniel?) Thanks, Praan