On Thu, Aug 19, 2021 at 6:53 PM Jason Gunthorpe [off-list ref] wrote:

On Wed, Aug 18, 2021 at 08:25:51PM -0700, Selvin Xavier wrote:

quoted

Atomics is not currently supported for VFs. Enabling only
for PFs.

Again, what is the user experience here? Does the device crash? QP
blow up?? Silently not work?

This is a host crash when pci_enable_atomic_ops_to_root is called with
a VF pci device (pdev->bus->self is NULL).  So, I want to  avoid
calling it for VF now.
crash> bt
PID: 4481   TASK: ffff89c6941b0000  CPU: 53  COMMAND: "bash"
 #0 [ffff9a94817136d8] machine_kexec at ffffffffb90601a4
 #1 [ffff9a9481713728] __crash_kexec at ffffffffb9190d5d
 #2 [ffff9a94817137f0] crash_kexec at ffffffffb9191c4d
 #3 [ffff9a9481713808] oops_end at ffffffffb9025cd6
 #4 [ffff9a9481713828] page_fault_oops at ffffffffb906e417
 #5 [ffff9a9481713888] exc_page_fault at ffffffffb9a0ad14
 #6 [ffff9a94817138b0] asm_exc_page_fault at ffffffffb9c00ace
    [exception RIP: pcie_capability_read_dword+28]
    RIP: ffffffffb952fd5c  RSP: ffff9a9481713960  RFLAGS: 00010246
    RAX: 0000000000000001  RBX: ffff89c6b1096000  RCX: 0000000000000000
    RDX: ffff9a9481713990  RSI: 0000000000000024  RDI: 0000000000000000
    RBP: 0000000000000080   R8: 0000000000000008   R9: ffff89c64341a2f8
    R10: 0000000000000002  R11: 0000000000000000  R12: ffff89c648bab000
    R13: 0000000000000000  R14: 0000000000000000  R15: ffff89c648bab0c8
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #7 [ffff9a9481713988] pci_enable_atomic_ops_to_root at ffffffffb95359a6
 #8 [ffff9a94817139c0] bnxt_qplib_determine_atomics at
ffffffffc08c1a33 [bnxt_re]
 #9 [ffff9a94817139d0] bnxt_re_dev_init at ffffffffc08ba2d1 [bnxt_re]
#10 [ffff9a9481713a78] bnxt_re_netdev_event at ffffffffc08bab8f [bnxt_re]
#11 [ffff9a9481713aa8] raw_notifier_call_chain at ffffffffb9102cbe
#12 [ffff9a9481713ad0] register_netdevice at ffffffffb9803ff3
#13 [ffff9a9481713b08] register_netdev at ffffffffb980410a
#14 [ffff9a9481713b18] bnxt_init_one at ffffffffc0349572 [bnxt_en]
#15 [ffff9a9481713b70] local_pci_probe at ffffffffb953b92f
#16 [ffff9a9481713ba0] pci_device_probe at ffffffffb953cf8f
#17 [ffff9a9481713be8] really_probe at ffffffffb9659619
#18 [ffff9a9481713c08] __driver_probe_device at ffffffffb96598fb
#19 [ffff9a9481713c28] driver_probe_device at ffffffffb965998f
#20 [ffff9a9481713c48] __device_attach_driver at ffffffffb9659cd2
#21 [ffff9a9481713c70] bus_for_each_drv at ffffffffb9657307
#22 [ffff9a9481713ca8] __device_attach at ffffffffb96593e0
#23 [ffff9a9481713ce8] pci_bus_add_device at ffffffffb9530b7a
#24 [ffff9a9481713d00] pci_iov_add_virtfn at ffffffffb955b1ca
#25 [ffff9a9481713d40] sriov_enable at ffffffffb955b54b
#26 [ffff9a9481713d90] bnxt_sriov_configure at ffffffffc034d913 [bnxt_en]
#27 [ffff9a9481713dd8] sriov_numvfs_store at ffffffffb955acb4
#28 [ffff9a9481713e10] kernfs_fop_write_iter at ffffffffb93f09ad
#29 [ffff9a9481713e48] new_sync_write at ffffffffb933b82c
#30 [ffff9a9481713ed0] vfs_write at ffffffffb933db64
#31 [ffff9a9481713f00] ksys_write at ffffffffb933dd99
#32 [ffff9a9481713f38] do_syscall_64 at ffffffffb9a07897
#33 [ffff9a9481713f50] entry_SYSCALL_64_after_hwframe at ffffffffb9c0007c
    RIP: 00007f450602f648  RSP: 00007ffe880869e8  RFLAGS: 00000246
    RAX: ffffffffffffffda  RBX: 0000000000000002  RCX: 00007f450602f648
    RDX: 0000000000000002  RSI: 0000555c566c4a60  RDI: 0000000000000001
    RBP: 0000555c566c4a60   R8: 000000000000000a   R9: 00007f45060c2580
    R10: 000000000000000a  R11: 0000000000000246  R12: 00007f45063026e0
    R13: 0000000000000002  R14: 00007f45062fd880  R15: 0000000000000002
    ORIG_RAX: 0000000000000001  CS: 0033  SS: 002b

I will update patch with this stack trace information.

Jason