[PATCH v10 03/13] iommu/arm-smmu-v3: Add ARM_SMMU_FEAT_EVTQ for the event queue

[Will Deacon]

On Sun, Aug 30, 2026 at 04:18:04PM -0700, Nicolin Chen wrote:
> The driver programs and enables the event queue unconditionally, while the
> PRI queue has an ARM_SMMU_FEAT_PRI gating each of its touch points. Yet a
> kdump kernel wants to leave both of the queues alone, which would take an
> is_kdump_kernel() test at every one of those places.
> 
> Add an ARM_SMMU_FEAT_EVTQ that the probe always sets, as the event queue is
> architecturally mandatory, and gate the queue's allocation, its interrupt
> and its CR0 and IRQ_CTRL enables on it, so that a later change can turn the
> queue off in a single place.
> 
> No functional change intended.
> 
> Suggested-by: Jason Gunthorpe <jgg at nvidia.com>
> Suggested-by: Robin Murphy <robin.murphy at arm.com>
> Assisted-by: Claude:claude-opus-5
> Signed-off-by: Nicolin Chen <nicolinc at nvidia.com>
> ---
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h |  1 +
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 79 +++++++++++++--------
>  2 files changed, 52 insertions(+), 28 deletions(-)

Sashiko has comments about the event queue MSI configuration for this patch.
Please can you have a look?

Will