Re: [PATCH v14 0/3] fix vt-d hard lockup when hotplug ATS capable device

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

On 2024/3/1 16:07, 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 byyehaorong@bytedance.com  on stable v6.7-rc4.
> patch [1-3] passed compiling on stable v6.8-rc4 (Baolu's rbtree branch).

This series has been queued for iommu next.

Best regards,
baolu