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Message-ID: <f7617140-0f9d-4907-aa8f-55894de830b0@linux.intel.com>
Date: Mon, 29 Jan 2024 13:16:23 +0800
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Subject: Re: [PATCH v12 0/5] fix vt-d hard lockup when hotplug ATS capable
 device
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
References: <20240129034924.817005-1-haifeng.zhao@linux.intel.com>
From: Ethan Zhao <haifeng.zhao@linux.intel.com>
In-Reply-To: <20240129034924.817005-1-haifeng.zhao@linux.intel.com>
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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