[Qemu-devel] [Bug 1284874] Re: Guest hangs during option rom loading with certain cards

[Bandan Das]

Comments from Alex Williamson :
> The sequence leading up to this is quite short.  We do standard PCI BAR
> sizing and setup, read the ROM, then do:
> 
> vfio: vfio_pci_write_config(0000:03:00.0, @0x78, 0x1, len=0x4)
> vfio: vfio_pci_write_config(0000:03:00.0, @0x80, 0x9430, len=0x4)
> vfio: vfio_pci_write_config(0000:03:00.0, @0x78, 0xa30c, len=0x4)
> vfio: vfio_pci_write_config(0000:03:00.0, @0x80, 0x7fffffff, len=0x4)
> vfio: vfio_pci_write_config(0000:03:00.0, @0x78, 0xa5dc, len=0x4)
> vfio: vfio_pci_write_config(0000:03:00.0, @0x80, 0x0, len=0x4)
> vfio: vfio_pci_write_config(0000:03:00.0, @0x78, 0xa2ec, len=0x4)
> vfio: vfio_pci_write_config(0000:03:00.0, @0x80, 0x3, len=0x4)
> vfio: vfio_pci_read_config(0000:03:00.0, @0x98, len=0x4) 200
> vfio: vfio_pci_write_config(0000:03:00.0, @0x78, 0xa408, len=0x4)
> vfio: vfio_pci_read_config(0000:03:00.0, @0x80, len=0x4) 8
> 
> vfio: vfio_pci_write_config(0000:03:00.0, @0x78, 0x86420, len=0x4)
> vfio: vfio_pci_write_config(0000:03:00.0, @0x80, 0x4, len=0x4)
> vfio: vfio_pci_write_config(0000:03:00.0, @0x78, 0x86420, len=0x4)
> vfio: vfio_pci_read_config(0000:03:00.0, @0x80, len=0x4) 8
> 
> The last 4 operations are repeated forever.

Based on the Linux driver we can see that 0x86420 is
MCP_REG_MCPR_NVM_SW_ARB which arbitrates software locking of the nvram
on the device.  A write of 4 seems to indicate that we want to lock port
1 for nvram access.  A successful lock would set bit 2 (0x4).  The value
0x8 is read back, so the lock was not successful and the ROM repeats
this forever.

Perhaps there's a problem with how the port number is selected?  It
seems suspicious that we're using port 1 here.

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https://bugs.launchpad.net/bugs/1284874

Title:
  Guest hangs during option rom loading with certain cards

Status in QEMU:
  New

Bug description:
  With a Broadcom Corporation NetXtreme II BCM57810 10 Gigabit Ethernet
  card, device assignment does not work. The guest hangs during option
  rom execution. Moreover, if an attempt is made to quit qemu when the
  guest is in the hung state, the card gets into an inoperable state.
  Only a powercycle then, restores the card back into working order,
  just unloading/loading the driver does not help.

  Qemu version  - 1.6.2 or current master
  Distribution - FC19
  Kernel Version - 3.12.9-201.fc19.x86_64

  Details of the card - 
   # ethtool -i p2p2
  driver: bnx2x
  version: 1.78.17-0
  firmware-version: bc 7.8.22
  bus-info: 0000:08:00.1
  supports-statistics: yes
  supports-test: yes
  supports-eeprom-access: yes
  supports-register-dump: yes
  supports-priv-flags: yes

  The output of lspci when the card is broken -
  03:00.0 Ethernet controller: Broadcom Corporation NetXtreme II BCM57810 10 
Gigabit Ethernet (rev ff) (prog-if ff)
        !!! Unknown header type 7f
        Kernel driver in use: bnx2x
  00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
  10: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
  20: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
  30: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff

  I will post if I get a chance to try out a newer  than 7.8.22 for the
  option rom and see if this issue is fixed. However it appears we need
  to have a unified approach to automatically avoid loading the rom
  based on certain criteria.  Manually, looking out for fixes to
  firmware and hard coding decisions based on those is neither desirable
  nor easy to maintain.

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