Re: [PATCH v12 0/5] fix vt-d hard lockup when hotplug ATS capable device

Ethan Zhao
2024-01-29T05:16:30Z

Bjorn,

On 1/29/2024 11:49 AM, Ethan Zhao wrote:
> This patchset is used to fix vt-d hard lockup reported when surprise
> unplug ATS capable endpoint device connects to system via PCIe switch
> as following topology.
>
> +-[0000:15]-+-00.0 Intel Corporation Ice Lake Memory Map/VT-d
> | +-00.1 Intel Corporation Ice Lake Mesh 2 PCIe
> | +-00.2 Intel Corporation Ice Lake RAS
> | +-00.4 Intel Corporation Device 0b23
> | \-01.0-[16-1b]----00.0-[17-1b]--+-00.0-[18]----00.0
> NVIDIA Corporation Device 2324
> | +-01.0-[19]----00.0
> Mellanox Technologies MT2910 Family [ConnectX-7]
>
> User brought endpoint device 19:00.0's link down by flapping it's hotplug
> capable slot 17:01.0 link control register, as sequence DLLSC response,
> pciehp_ist() will unload device driver and power it off, durning device
> driver is unloading an iommu device-TLB invalidation (Intel VT-d spec, or
> 'ATS Invalidation' in PCIe spec) request issued to that link down device,
> thus a long time completion/timeout waiting in interrupt context causes
> continuous hard lockup warnning and system hang.
>
> Other detail, see every patch commit log.
>
> patch [1&2] were tested by yehaorong@bytedance.com on stable v6.7-rc4.
> patch [1-5] passed compiling on stable v6.8-rc2.
>
> change log:
> v12:
> - use base-commit tag to format patch.
> - fix building issue on v6.8-rc2 repported by lkp@intel.com.
> v11:
> - update per latest comment and suggestion from Baolu and YiLiu.
> - split refactoring patch into two patches, [3/5] for simplify parameters
> and [4/5] for pdev parameter passing.
> - re-order patches.
> - fold target device presence check into qi_check_fault().
> - combine patch[2][5] in v10 into one patch[5].
> - some commit description correctness.
> - add fixes tag to patch[2/5].
> - rebased on 6.8rc1
> v10:
> - refactor qi_submit_sync() and its callers to get pci_dev instance, as
> Kevin pointed out add target_flush_dev to iommu is not right.
> v9:
> - unify all spelling of ATS Invalidation adhere to PCIe spec per Bjorn's
> suggestion.
> v8:
> - add a patch to break the loop for timeout device-TLB invalidation, as
> Bjorn said there is possibility device just no response but not gone.
> v7:
> - reorder patches and revise commit log per Bjorn's guide.
> - other code and commit log revise per Lukas' suggestion.
> - rebased to stable v6.7-rc6.
> v6:
> - add two patches to break out device-TLB invalidation if device is gone.
> v5:
> - add a patch try to fix the rare case (surprise remove a device in
> safe removal process). not work because surprise removal handling can't
> re-enter when another safe removal is in process.
> v4:
> - move the PCI device state checking after ATS per Baolu's suggestion.
> v3:
> - fix commit description typo.
> v2:
> - revise commit[1] description part according to Lukas' suggestion.
> - revise commit[2] description to clarify the issue's impact.
> v1:
> - https://lore.kernel.org/lkml/20231213034637.2603013-1-haifeng.zhao@
> linux.intel.com/T/
>
>
> Thanks,
> Ethan
>
>
>
>
> Ethan Zhao (5):
> PCI: make pci_dev_is_disconnected() helper public for other drivers
> iommu/vt-d: don't issue ATS Invalidation request when device is
> disconnected
> iommu/vt-d: simplify parameters of qi_submit_sync() ATS invalidation
> callers
> iommu/vt-d: pass pdev parameter for qi_check_fault() and refactor
> callers
> iommu/vt-d: improve ITE fault handling if target device isn't present
>
> drivers/iommu/intel/dmar.c | 71 +++++++++++++++++++++++------
> drivers/iommu/intel/iommu.c | 29 +++---------
> drivers/iommu/intel/iommu.h | 20 ++++----
> drivers/iommu/intel/irq_remapping.c | 2 +-
> drivers/iommu/intel/nested.c | 9 +---
> drivers/iommu/intel/pasid.c | 12 ++---
> drivers/iommu/intel/svm.c | 23 +++++-----
> drivers/pci/pci.h | 5 --
> include/linux/pci.h | 5 ++
> 9 files changed, 98 insertions(+), 78 deletions(-)
>
>
> base-commit: 41bccc98fb7931d63d03f326a746ac4d429c1dd3

I got mail delivery failure message from Gmail for "unsolicited mail", I
don't

know if you could read it by linux-pci mail list. the vt-d maintainer is
going

to pick up this patchset, may I ask your 'ack' for the pci change if no
more

comment from you ?

Thanks,

Ethan