lkml.org 
[lkml]   [2024]   [Apr]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH v4 6/7] iommu/dma: Centralise iommu_setup_dma_ops()
From
On 2024-04-29 5:31 pm, Dmitry Baryshkov 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

Hmm, a context fault implies that the device did get attached to a DMA
domain, thus has successfully been through __iommu_probe_device(), yet
somehow still didn't get the right DMA ops (since that "IOVA" looks more
like a PA to me). Do you see the "Adding to IOMMU group..." message for
this device, and/or any other relevant messages or errors before this
point? I'm guessing there's a fair chance probe deferral might be
involved as well. I'd like to understand what path(s) this ends up
taking through __iommu_probe_device() and of_dma_configure(), or at
least the number and order of probe attempts between the UFS and SMMU
drivers.

I'll stare at the code in the morning and see if I can spot any
overlooked ways in which what I think might be happening could happen,
but any more info to help narrow it down would be much appreciated.

Thanks,
Robin.

> [ 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
>

\
 
 \ /
  Last update: 2024-04-30 00:27    [W:0.385 / U:0.348 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site