[Qemu-devel] [Bug 744195] [NEW] guest cannot boot with 8 VFs or more

[Yongjie Ren]

Public bug reported:

Environment:
------------
Host OS (ia32/ia32e/IA64):All
Guest OS (ia32/ia32e/IA64): All
Guest OS Type (Linux/Windows): Linux
kvm.git Commit:a3e2cba1e702cfe15e2ebb20a75b88f02c834d3f
qemu-kvm Commit:2c9bb5d4e5ae3b12ad71bd6a0c1b32003661f53a
Host Kernel Version:2.6.38+
Hardware:Westmere-EP / Sandy Bridge


Bug detailed description:
--------------------------
Guest cannot boot with 8 VFs or more VFs, but guest can boot with 7 VFs.
If you assign hot-plug VFs, after you assigning the 8th VF, you may get the
following message in host. 
"kvm_alloc_slot: no free slot available".
And the guest aborts.

Reproduce steps:
----------------
1.try to create a guest with 8 VFs:(the guest cannot boot)
  qemu-system-x86_64 -smp 2 -m 1024 -net none -hda /root/rhel6.1-beta1.img
-device pci-assign,host=04:10.0 -device pci-assign,host=04:10.1 -device
pci-assign,host=04:10.2 -device pci-assign,host=04:10.3 -device
pci-assign,host=04:10.4 -device pci-assign,host=04:10.5 -device
pci-assign,host=04:10.6 -device pci-assign,host=04:10.7

2.If you want to assign 8 hot-plug VFs, you may use following command in qemu
monitor after you start a guest.
"device_add pci-assign,host=00:19.0,id=my_nic"

** Affects: qemu
     Importance: Undecided
         Status: New

** Bug watch added: SourceForge.net Tracker #2847560
   http://sourceforge.net/support/tracker.php?aid=2847560

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https://bugs.launchpad.net/bugs/744195

Title:
  guest cannot boot with 8 VFs or more

Status in QEMU:
  New

Bug description:
  Environment:
  ------------
  Host OS (ia32/ia32e/IA64):All
  Guest OS (ia32/ia32e/IA64): All
  Guest OS Type (Linux/Windows): Linux
  kvm.git Commit:a3e2cba1e702cfe15e2ebb20a75b88f02c834d3f
  qemu-kvm Commit:2c9bb5d4e5ae3b12ad71bd6a0c1b32003661f53a
  Host Kernel Version:2.6.38+
  Hardware:Westmere-EP / Sandy Bridge

  
  Bug detailed description:
  --------------------------
  Guest cannot boot with 8 VFs or more VFs, but guest can boot with 7 VFs.
  If you assign hot-plug VFs, after you assigning the 8th VF, you may get the
  following message in host. 
  "kvm_alloc_slot: no free slot available".
  And the guest aborts.

  Reproduce steps:
  ----------------
  1.try to create a guest with 8 VFs:(the guest cannot boot)
    qemu-system-x86_64 -smp 2 -m 1024 -net none -hda /root/rhel6.1-beta1.img
  -device pci-assign,host=04:10.0 -device pci-assign,host=04:10.1 -device
  pci-assign,host=04:10.2 -device pci-assign,host=04:10.3 -device
  pci-assign,host=04:10.4 -device pci-assign,host=04:10.5 -device
  pci-assign,host=04:10.6 -device pci-assign,host=04:10.7

  2.If you want to assign 8 hot-plug VFs, you may use following command in qemu
  monitor after you start a guest.
  "device_add pci-assign,host=00:19.0,id=my_nic"