[PATCH v13 0/3] fix vt-d hard lockup when hotplug ATS capable device

[Ethan Zhao]

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@xxxxxxxxxxxxx on stable v6.7-rc4.
patch [1-3] passed compiling on stable v6.8-rc4 (Baolu's rbtree branch).

change log:
v13:
- rebased on Baolu's rbtree patchset.
- removed refactor patches [3/5][4/5] in v12.
- amend commit description of patch[3/3].
v12:
- use base-commit tag to format patch.
- fix building issue on v6.8-rc2 repported by lkp@xxxxxxxxx.
- https://lkml.org/lkml/2024/1/28/535
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
- https://lkml.org/lkml/2024/1/25/1314
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 (3):
  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: improve ITE fault handling if target device isn't valid

 drivers/iommu/intel/dmar.c  | 25 +++++++++++++++++++++++++
 drivers/iommu/intel/pasid.c |  3 +++
 drivers/pci/pci.h           |  5 -----
 include/linux/pci.h         |  5 +++++
 4 files changed, 33 insertions(+), 5 deletions(-)


base-commit: e60bf5aa1a74c0652cd12d0cdc02f5c2b5fe5c74
-- 
2.31.1