Re: [PATCH 0/4] PCI/CXL: Guard reset recovery against inaccessible devices

[Cheatham, Benjamin]

I noticed that linux-pci isn't CC'ed. Seems like a big oversight considering 3/4 of the patches
are in the PCI code...

I'd resend to this with that list in the CC, or at least include it in a v2.

Thanks,
Ben

On 9/28/2026 9:04 PM, Richard Cheng wrote:
> During FLR testing, PCI configuration reads returned all ones. The
> kernel could mistake this for reset completion and proceed with MSI-X
> restoration. The resulting MMIO access triggered DPC containment.
> 
> This series addresses four issues:
> 
> 1. Reject all-ones responses in pci_dev_wait(). Use Command-register
>     polling for VFs, whose Vendor ID legitimately reads as all ones.
> 
> 2. Return -ETIMEDOUT when readiness polling expires, preventing fallback
>     to another reset method.
> 
> 3. Check configuration accessibility before restoring PCI state, while
>     preserving driver reset callbacks.
> 
> 4. Skip CXL decoder MMIO accesses when configuration is inaccessible
>     or memory decoding is disabled.
> 
> 
> Best regards,
> Richard Cheng.
> 
> Richard Cheng (4):
>   PCI: Reject all-ones responses in pci_dev_wait()
>   PCI: Return -ETIMEOUT when reset readiness polling expires
>   PCI: Skip state restoration when configuration is inaccessible
>   cxl/pci: Guard decoder accesses after reset
> 
>  drivers/cxl/pci.c |  6 ++++++
>  drivers/pci/pci.c | 16 +++++++++-------
>  2 files changed, 15 insertions(+), 7 deletions(-)
> 
> 
> base-commit: 9eb6419022d81aac6d1d9ead0e1865b451153da5