Re: [PATCH v4 6/7] iommu/dma: Centralise iommu_setup_dma_ops()

[Konrad Dybcio <konrad.dybcio@linaro.org>]

On 29.04.2024 11:26 PM, Dmitry Baryshkov wrote:
> On Mon, 29 Apr 2024 at 19:31, Dmitry Baryshkov
> <dmitry.baryshkov@linaro.org> wrote:
>>
>> On Fri, Apr 19, 2024 at 05:54:45PM +0100, Robin Murphy wrote:
>>> It's somewhat hard to see, but arm64's arch_setup_dma_ops() should only
>>> ever call iommu_setup_dma_ops() after a successful iommu_probe_device(),
>>> which means there should be no harm in achieving the same order of
>>> operations by running it off the back of iommu_probe_device() itself.
>>> This then puts it in line with the x86 and s390 .probe_finalize bodges,
>>> letting us pull it all into the main flow properly. As a bonus this lets
>>> us fold in and de-scope the PCI workaround setup as well.
>>>
>>> At this point we can also then pull the call up inside the group mutex,
>>> and avoid having to think about whether iommu_group_store_type() could
>>> theoretically race and free the domain if iommu_setup_dma_ops() ran just
>>> *before* iommu_device_use_default_domain() claims it... Furthermore we
>>> replace one .probe_finalize call completely, since the only remaining
>>> implementations are now one which only needs to run once for the initial
>>> boot-time probe, and two which themselves render that path unreachable.
>>>
>>> This leaves us a big step closer to realistically being able to unpick
>>> the variety of different things that iommu_setup_dma_ops() has been
>>> muddling together, and further streamline iommu-dma into core API flows
>>> in future.
>>>
>>> Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> # For Intel IOMMU
>>> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
>>> Tested-by: Hanjun Guo <guohanjun@huawei.com>
>>> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
>>> ---
>>> v2: Shuffle around to make sure the iommu_group_do_probe_finalize() case
>>>     is covered as well, with bonus side-effects as above.
>>> v3: *Really* do that, remembering the other two probe_finalize sites too.
>>> ---
>>>  arch/arm64/mm/dma-mapping.c  |  2 --
>>>  drivers/iommu/amd/iommu.c    |  8 --------
>>>  drivers/iommu/dma-iommu.c    | 18 ++++++------------
>>>  drivers/iommu/dma-iommu.h    | 14 ++++++--------
>>>  drivers/iommu/intel/iommu.c  |  7 -------
>>>  drivers/iommu/iommu.c        | 20 +++++++-------------
>>>  drivers/iommu/s390-iommu.c   |  6 ------
>>>  drivers/iommu/virtio-iommu.c | 10 ----------
>>>  include/linux/iommu.h        |  7 -------
>>>  9 files changed, 19 insertions(+), 73 deletions(-)
>>
>> This patch breaks UFS on Qualcomm SC8180X Primus platform:
>>
>>
>> [    3.846856] arm-smmu 15000000.iommu: Unhandled context fault: fsr=0x402, iova=0x1032db3e0, fsynr=0x130000, cbfrsynra=0x300, cb=4
>> [    3.846880] ufshcd-qcom 1d84000.ufshc: ufshcd_check_errors: saved_err 0x20000 saved_uic_err 0x0
>> [    3.846929] host_regs: 00000000: 1587031f 00000000 00000300 00000000
>> [    3.846935] host_regs: 00000010: 01000000 00010217 00000000 00000000
>> [    3.846941] host_regs: 00000020: 00000000 00070ef5 00000000 00000000
>> [    3.846946] host_regs: 00000030: 0000000f 00000001 00000000 00000000
>> [    3.846951] host_regs: 00000040: 00000000 00000000 00000000 00000000
>> [    3.846956] host_regs: 00000050: 032db000 00000001 00000000 00000000
>> [    3.846962] host_regs: 00000060: 00000000 80000000 00000000 00000000
>> [    3.846967] host_regs: 00000070: 032dd000 00000001 00000000 00000000
>> [    3.846972] host_regs: 00000080: 00000000 00000000 00000000 00000000
>> [    3.846977] host_regs: 00000090: 00000016 00000000 00000000 0000000c
>> [    3.847074] ufshcd-qcom 1d84000.ufshc: ufshcd_err_handler started; HBA state eh_fatal; powered 1; shutting down 0; saved_err = 131072; saved_uic_err = 0; force_reset = 0
>> [    4.406550] ufshcd-qcom 1d84000.ufshc: ufshcd_verify_dev_init: NOP OUT failed -11
>> [    4.417953] ufshcd-qcom 1d84000.ufshc: ufshcd_async_scan failed: -11
> 
> Just to confirm: reverting f091e93306e0 ("dma-mapping: Simplify
> arch_setup_dma_ops()") and b67483b3c44e ("iommu/dma: Centralise
> iommu_setup_dma_ops()" fixes the issue for me. Please ping me if you'd
> like me to test a fix.

This also triggers a different issue (that also comes down to "ufs bad") on
another QC platform (SM8550):

[    4.282098] scsi host0: ufshcd
[    4.315970] ufshcd-qcom 1d84000.ufs: ufshcd_check_errors: saved_err 0x20000 saved_uic_err 0x0
[    4.330155] host_regs: 00000000: 3587031f 00000000 00000400 00000000
[    4.343955] host_regs: 00000010: 01000000 00010217 00000000 00000000
[    4.356027] host_regs: 00000020: 00000000 00070ef5 00000000 00000000
[    4.370136] host_regs: 00000030: 0000000f 00000003 00000000 00000000
[    4.376662] host_regs: 00000040: 00000000 00000000 00000000 00000000
[    4.383192] host_regs: 00000050: 85109000 00000008 00000000 00000000
[    4.389719] host_regs: 00000060: 00000000 80000000 00000000 00000000
[    4.396245] host_regs: 00000070: 8510a000 00000008 00000000 00000000
[    4.402773] host_regs: 00000080: 00000000 00000000 00000000 00000000
[    4.409298] host_regs: 00000090: 00000016 00000000 00000000 0000000c
[    4.415900] arm-smmu 15000000.iommu: Unhandled context fault: fsr=0x402, iova=0x8851093e0, fsynr=0x3b0001, cbfrsynra=0x60, cb=2
[    4.416135] ufshcd-qcom 1d84000.ufs: ufshcd_err_handler started; HBA state eh_fatal; powered 1; shutting down 0; saved_err = 131072; saved_uic_err = 0; force_reset = 0
[    4.951750] ufshcd-qcom 1d84000.ufs: ufshcd_verify_dev_init: NOP OUT failed -11
[    4.960644] ufshcd-qcom 1d84000.ufs: ufshcd_async_scan failed: -11

Reverting the commits Dmitry mentioned also fixes this.

Konrad