[PATCH 0/2] PCI: Workaround for bus reset on Cavium cn8xxx root ports

[David Daney]

With the recent improvements in arm64 and vfio-pci, we are seeing
failures like this (on cn8890 based systems):

[  235.622361] Unhandled fault: synchronous external abort (0x96000210) at 0xfffffc00c1000100
[  235.630625] Internal error: : 96000210 [#1] PREEMPT SMP
.
.
.
[  236.208820] [<fffffc0008411250>] pci_generic_config_read+0x38/0x9c
[  236.214992] [<fffffc0008435ed4>] thunder_pem_config_read+0x54/0x1e8
[  236.221250] [<fffffc0008411620>] pci_bus_read_config_dword+0x74/0xa0
[  236.227596] [<fffffc000841853c>] pci_find_next_ext_capability.part.15+0x40/0xb8
[  236.234896] [<fffffc0008419428>] pci_find_ext_capability+0x20/0x30
[  236.241068] [<fffffc0008423e2c>] pci_restore_vc_state+0x34/0x88
[  236.246979] [<fffffc000841af3c>] pci_restore_state.part.37+0x2c/0x1fc
[  236.253410] [<fffffc000841b174>] pci_dev_restore+0x4c/0x50
[  236.258887] [<fffffc000841b19c>] pci_bus_restore+0x24/0x4c
[  236.264362] [<fffffc000841c2dc>] pci_try_reset_bus+0x7c/0xa0
[  236.270021] [<fffffc00060a1ab0>] vfio_pci_ioctl+0xc34/0xc3c [vfio_pci]
[  236.276547] [<fffffc0005eb0410>] vfio_device_fops_unl_ioctl+0x20/0x30 [vfio]
[  236.283587] [<fffffc000824b314>] do_vfs_ioctl+0xac/0x744
[  236.288890] [<fffffc000824ba30>] SyS_ioctl+0x84/0x98
[  236.293846] [<fffffc0008082ca0>] __sys_trace_return+0x0/0x4

These are caused by the inability of the PCIe root port and Intel
e1000e to sucessfully do a bus reset.

The proposed fix is to not do a bus reset on these systems.

David Daney (2):
  PCI: Allow PCI_DEV_FLAGS_NO_BUS_RESET to be used on bus device.
  PCI: Avoid bus reset for Cavium cn8xxx root ports.

 drivers/pci/pci.c    | 4 ++++
 drivers/pci/quirks.c | 8 ++++++++
 2 files changed, 12 insertions(+)

-- 
2.9.4