Re: [PATCH v4 0/8] iommu: Remove IOMMU_DEV_FEAT_SVA/_IOPF

[Baolu Lu <baolu.lu@linux.intel.com>]

On 2025/3/13 18:57, Zhangfei Gao wrote:
> On Thu, 13 Mar 2025 at 17:51, Zhangfei Gao<zhangfei.gao@linaro.org> wrote:
>> Hi, Baolu
>>
>> On Thu, 13 Mar 2025 at 13:19, Lu Baolu<baolu.lu@linux.intel.com> wrote:
>>> The new method for driver fault reporting support relies on the domain
>>> to specify a iopf_handler. The driver should detect this and setup the
>>> HW when fault capable domains are attached.
>>>
>>> Move SMMUv3 to use this method and have VT-D validate support during
>>> attach so that all three fault capable drivers have a no-op FEAT_SVA and
>>> _IOPF. Then remove them.
>>>
>>> This was initiated by Jason. I'm following up to remove FEAT_IOPF and
>>> further clean up.
>>>
>>> The whole series is also available at github:
>>> https://github.com/LuBaolu/intel-iommu/commits/iommu_no_feat-v4
>> I got an issue on this branch.
>>
>> Linux 6.14-rc4 + iommu_no_feat-v2
>> drivers/pci/quirks.c
>> quirk_huawei_pcie_sva will set dma-can-stall first
>> arm_smmu_probe_device will check dma-can-stall and set stall_enabled
>> accordingly.
> This working branch arm_smmu_probe_device is called from pci_bus_add_device
> So pci_fixup_device is called first
> 
> [ 1121.314405]  arm_smmu_probe_device+0x48/0x450
> [ 1121.314410]  __iommu_probe_device+0xc4/0x3c8
> [ 1121.314412]  iommu_probe_device+0x40/0x90
> [ 1121.314414]  acpi_dma_configure_id+0xb4/0x100
> [ 1121.314417]  pci_dma_configure+0xf8/0x108
> [ 1121.314421]  really_probe+0x78/0x278
> [ 1121.314425]  __driver_probe_device+0x80/0x140
> [ 1121.314427]  driver_probe_device+0x48/0x130
> [ 1121.314430]  __device_attach_driver+0xc0/0x108
> [ 1121.314432]  bus_for_each_drv+0x8c/0xf8
> [ 1121.314435]  __device_attach+0x104/0x1a0
> [ 1121.314437]  device_attach+0x1c/0x30
> [ 1121.314440]  pci_bus_add_device+0xb8/0x1f0
> [ 1121.314442]  pci_iov_add_virtfn+0x2ac/0x300
> [ 1121.314446]  sriov_enable+0x204/0x468
> [ 1121.314447]  pci_enable_sriov+0x20/0x40
> 
> 
>> This branch
>> arm_smmu_probe_device happens first, when dma-can-stall = 0, so
>> stall_enabled =0.
>> Then drivers/pci/quirks.c: quirk_xxx happens
> This not working branch: Linux 6.14-rc6 + iommu_no_feat-v4
> arm_smmu_probe_device is called by pci_device_add
> Then call pci_bus_add_device -> pci_fixup_device
> 
>    215.072859]  arm_smmu_probe_device+0x48/0x450
> [  215.072871]  __iommu_probe_device+0xc0/0x468
> [  215.072875]  iommu_probe_device+0x40/0x90
> [  215.072877]  iommu_bus_notifier+0x38/0x68
> [  215.072879]  notifier_call_chain+0x80/0x148
> [  215.072886]  blocking_notifier_call_chain+0x50/0x80
> [  215.072889]  bus_notify+0x44/0x68
> [  215.072896]  device_add+0x580/0x768
> [  215.072898]  pci_device_add+0x1e8/0x568
> [  215.072906]  pci_iov_add_virtfn+0x198/0x300
> [  215.072910]  sriov_enable+0x204/0x468
> [  215.072912]  pci_enable_sriov+0x20/0x40
> 
> pci_iov_add_virtfn:
> pci_device_add(virtfn, virtfn->bus);
> pci_bus_add_device(virtfn); -> pci_fixup_device(pci_fixup_final, dev);

This probably is not caused by this patch series. Can you please have a
try with the next branch of iommu tree? Or the latest linux-next tree?

https://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux.git

Thanks,
baolu