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From: Ethan Zhao <haifeng.zhao@linux.intel.com>
To: baolu.lu@linux.intel.com,
	bhelgaas@google.com,
	robin.murphy@arm.com,
	jgg@ziepe.ca
Cc: kevin.tian@intel.com,
	dwmw2@infradead.org,
	will@kernel.org,
	lukas@wunner.de,
	yi.l.liu@intel.com,
	iommu@lists.linux.dev,
	linux-kernel@vger.kernel.org,
	linux-pci@vger.kernel.org,
	Ethan Zhao <haifeng.zhao@linux.intel.com>
Subject: [PATCH v11 0/5] fix vt-d hard lockup when hotplug ATS capable device
Date: Thu, 25 Jan 2024 20:39:57 -0500
Message-Id: <20240126014002.481294-1-haifeng.zhao@linux.intel.com>
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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 v6.8rc1.

change log:
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         | 26 +++--------
 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           | 13 +++---
 drivers/pci/pci.h                   |  5 --
 include/linux/pci.h                 |  5 ++
 9 files changed, 93 insertions(+), 70 deletions(-)

-- 
2.31.1