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

Tue Apr 30 05:33:20 PDT 2024

On 30/04/2024 1:23 pm, Konrad Dybcio wrote:
> On 29.04.2024 11:26 PM, Dmitry Baryshkov wrote:
>> On Mon, 29 Apr 2024 at 19:31, Dmitry Baryshkov
>> <dmitry.baryshkov at 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 at linux.intel.com> # For Intel IOMMU
>>>> Reviewed-by: Jason Gunthorpe <jgg at nvidia.com>
>>>> Tested-by: Hanjun Guo <guohanjun at huawei.com>
>>>> Signed-off-by: Robin Murphy <robin.murphy at 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.

Yeah, It'll be the same thing - doesn't really matter exactly *how* the 
UFS goes wrong due to the SMMU blocking it, the issue is that the SMMU 
is erroneously blocking it in the first place due to a DMA ops mixup. 
Fix is now here:

https://lore.kernel.org/linux-iommu/d4cc20cbb0c45175e98dd76bf187e2ad6421296d.1714472573.git.robin.murphy@arm.com/

Thanks,
Robin.