ACK/Cmnt: [SRU][F:linux-aws][PATCH 0/1] Backport "iommu/arm-smmu-v3: Don't reserve implementation defined register space"

[John Cabaj]

On 3/26/25 3:54 PM, Magali Lemes wrote:
> BugLink: https://bugs.launchpad.net/bugs/2067864

Launchpad bug will need the SRU justification format given below in the 
description.


John

> 
> [Impact]
> In order to solve boot issues with new instance types running the 5.4 kernels,
> AWS has requested a backport of upstream commit 52f3fab0067d
> ("iommu/arm-smmu-v3: Don't reserve implementation defined register space").
> 
> [Fix]
> There was a conflict when adding arm_smmu_ioremap() due to the current
> context missing ab246774713e ("iommu/arm-smmu-v3: Unregister IOMMU and
> bus ops on device removal").
> 
> [Test]
> It's been tested that the new instances can boot successfully with the AWS 5.4
> kernels with this patch applied.
> 
> [Where problems could occur]
> This touches probing of the ARM SMMUv3 driver, which might lead to boot
> failures or system instability.
> 
> [Other info]
> SF #00407928
> 
> Jean-Philippe Brucker (1):
>    iommu/arm-smmu-v3: Don't reserve implementation defined register space
> 
>   drivers/iommu/arm-smmu-v3.c | 35 +++++++++++++++++++++++++++++++----
>   1 file changed, 31 insertions(+), 4 deletions(-)
>