[Qemu-devel] [Bug 1456804] Re: kvm_irqchip_commit_routes: Assertion `ret == 0' failed.

[Alex Williamson <alex.l.williamson@gmail.com>]

This appears to address it in QEMU v2.4:

commit 6652d0811c9463fbfb2d2d1cb2ec03f388145c5f
Author: Jason Wang <jasowang@redhat.com>
Date:   Wed May 27 16:26:07 2015 +0800

    virtio-pci: don't try to mask or unmask vqs without notifiers
    
    We should validate the vq index against nvqs_with_notifiers. Otherwise we may
    try to mask or unmask vector for vqs without notifiers (e.g control vq). This
    will lead qemu abort on kvm_irqchip_commit_routes() when trying to boot win8.1
    guest.
    
    Fixes 851c2a75a6e80c8aa5e713864d98cfb512e7229b ("virtio-pci: speedup MSI-X
    masking and unmasking")
    
    Reported-by: Alex Williamson <alex.williamson@redhat.com>
    Signed-off-by: Jason Wang <jasowang@redhat.com>
    Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
    Signed-off-by: Michael S. Tsirkin <mst@redhat.com>


** Changed in: qemu
       Status: Incomplete => Fix Released

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https://bugs.launchpad.net/bugs/1456804

Title:
  kvm_irqchip_commit_routes: Assertion `ret == 0' failed.

Status in QEMU:
  Fix Released

Bug description:
  During win8.1 boot on qemu.git
  eba05e922e8e7f307bc5d4104a78797e55124e97, kernel 4.1-rc4, I get the
  following assert:

  qemu-system-x86_64: /net/gimli/home/alwillia/Work/qemu.git/kvm-
  all.c:1033: kvm_irqchip_commit_routes: Assertion `ret == 0' failed.

  Bisected to:

  commit 851c2a75a6e80c8aa5e713864d98cfb512e7229b
  Author: Jason Wang <jasowang@redhat.com>
  Date:   Thu Apr 23 14:21:47 2015 +0800

      virtio-pci: speedup MSI-X masking and unmasking
      
      This patch tries to speed up the MSI-X masking and unmasking through
      the mapping between vector and queues. With this patch it will there's
      no need to go through all possible virtqueues, which may help to
      reduce the time spent when doing MSI-X masking/unmasking a single
      vector when more than hundreds or even thousands of virtqueues were
      supported.
      
      Tested with 80 queue pairs virito-net-pci by changing the smp affinity
      in the background and doing netperf in the same time:
      
      Before the patch:
      5711.70 Gbits/sec
      After the patch:
      6830.98 Gbits/sec
      
      About 19.6% improvements in throughput.
      
      Cc: Michael S. Tsirkin <mst@redhat.com>
      Signed-off-by: Jason Wang <jasowang@redhat.com>
      Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
      Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

  Backtrace:

  Program received signal SIGABRT, Aborted.
  [Switching to Thread 0x7f32fffff700 (LWP 23059)]
  0x00007f33187438d7 in raise () from /lib64/libc.so.6
  (gdb) bt
  #0  0x00007f33187438d7 in raise () at /lib64/libc.so.6
  #1  0x00007f331874553a in abort () at /lib64/libc.so.6
  #2  0x00007f331873c47d in __assert_fail_base () at /lib64/libc.so.6
  #3  0x00007f331873c532 in  () at /lib64/libc.so.6
  #4  0x000055e0252fed5b in kvm_irqchip_commit_routes (s=0x55e027ce17e0)
      at /net/gimli/home/alwillia/Work/qemu.git/kvm-all.c:1033
  #5  0x000055e0252fef46 in kvm_update_routing_entry (s=0x55e027ce17e0, new_entry=0x7f32ffffe4a0) at /net/gimli/home/alwillia/Work/qemu.git/kvm-all.c:1078
  #6  0x000055e0252ff78e in kvm_irqchip_update_msi_route (s=0x55e027ce17e0, virq=0, msg=...) at /net/gimli/home/alwillia/Work/qemu.git/kvm-all.c:1282
  #7  0x000055e0255899a0 in virtio_pci_vq_vector_unmask (proxy=0x55e02a0ee580, queue_no=2, vector=2, msg=...) at hw/virtio/virtio-pci.c:588
  #8  0x000055e025589b76 in virtio_pci_vector_unmask (dev=0x55e02a0ee580, vector=2, msg=...) at hw/virtio/virtio-pci.c:641
  #9  0x000055e0255186f0 in msix_set_notifier_for_vector (dev=0x55e02a0ee580, vector=2) at hw/pci/msix.c:513
  #10 0x000055e0255187ee in msix_set_vector_notifiers (dev=0x55e02a0ee580, use_notifier=0x55e025589ad2 <virtio_pci_vector_unmask>, release_notifier=0x55e025589c0c <virtio_pci_vector_mask>, poll_notifier=0x55e025589cb1 <virtio_pci_vector_poll>) at hw/pci/msix.c:540
  #11 0x000055e02558a1f0 in virtio_pci_set_guest_notifiers (d=0x55e02a0ee580, nvqs=2, assign=true) at hw/virtio/virtio-pci.c:794
  #12 0x000055e02533c2bc in vhost_net_start (dev=0x55e02a0eef90, ncs=0x55e02a866ac0, total_queues=1)
      at /net/gimli/home/alwillia/Work/qemu.git/hw/net/vhost_net.c:318
  #13 0x000055e025336dce in virtio_net_vhost_status (n=0x55e02a0eef90, status=7 '\a') at /net/gimli/home/alwillia/Work/qemu.git/hw/net/virtio-net.c:146
  #14 0x000055e025336e78 in virtio_net_set_status (vdev=0x55e02a0eef90, status=7 '\a') at /net/gimli/home/alwillia/Work/qemu.git/hw/net/virtio-net.c:165
  #15 0x000055e0253504c6 in virtio_set_status (vdev=0x55e02a0eef90, val=7 '\a')
      at /net/gimli/home/alwillia/Work/qemu.git/hw/virtio/virtio.c:551
  #16 0x000055e025588d6d in virtio_ioport_write (opaque=0x55e02a0ee580, addr=18, val=7) at hw/virtio/virtio-pci.c:259
  #17 0x000055e0255891d1 in virtio_pci_config_write (opaque=0x55e02a0ee580, addr=18, val=7, size=1) at hw/virtio/virtio-pci.c:385
  #18 0x000055e025303155 in memory_region_write_accessor (mr=0x55e02a0eee00, addr=18, value=0x7f32ffffe908, size=1, shift=0, mask=255, attrs=...)
      at /net/gimli/home/alwillia/Work/qemu.git/memory.c:457
  #19 0x000055e025303308 in access_with_adjusted_size (addr=18, value=0x7f32ffffe908, size=1, access_size_min=1, access_size_max=4, access=
      0x55e0253030d0 <memory_region_write_accessor>, mr=0x55e02a0eee00, attrs=...) at /net/gimli/home/alwillia/Work/qemu.git/memory.c:516
  #20 0x000055e025305b15 in memory_region_dispatch_write (mr=0x55e02a0eee00, addr=18, data=7, size=1, attrs=...)
      at /net/gimli/home/alwillia/Work/qemu.git/memory.c:1166
  #21 0x000055e0252b68eb in address_space_rw (as=0x55e025b71a80 <address_space_io>, addr=49458, attrs=..., buf=0x7f3322f48000 "\a", len=1, is_write=true)
      at /net/gimli/home/alwillia/Work/qemu.git/exec.c:2363
  #22 0x000055e02530041e in kvm_handle_io (port=49458, attrs=..., data=0x7f3322f48000, direction=1, size=1, count=1)
      at /net/gimli/home/alwillia/Work/qemu.git/kvm-all.c:1679
  #23 0x000055e025300914 in kvm_cpu_exec (cpu=0x55e02a1383a0)
  ---Type <return> to continue, or q <return> to quit---
      at /net/gimli/home/alwillia/Work/qemu.git/kvm-all.c:1839
  #24 0x000055e0252e8062 in qemu_kvm_cpu_thread_fn (arg=0x55e02a1383a0)
      at /net/gimli/home/alwillia/Work/qemu.git/cpus.c:947
  #25 0x00007f3321b2352a in start_thread () at /lib64/libpthread.so.0
  #26 0x00007f331880f22d in clone () at /lib64/libc.so.6

  VM XML (-snapshot added only for bisect):

  <domain type='kvm' id='8' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>
    <name>Steam</name>
    <uuid>79f39860-d659-426b-89e8-90cb46ee57c6</uuid>
    <memory unit='KiB'>4194304</memory>
    <currentMemory unit='KiB'>4194304</currentMemory>
    <memoryBacking>
      <hugepages/>
    </memoryBacking>
    <vcpu placement='static'>4</vcpu>
    <cputune>
      <vcpupin vcpu='0' cpuset='0'/>
      <vcpupin vcpu='1' cpuset='1'/>
      <vcpupin vcpu='2' cpuset='2'/>
      <vcpupin vcpu='3' cpuset='3'/>
    </cputune>
    <resource>
      <partition>/machine</partition>
    </resource>
    <os>
      <type arch='x86_64' machine='pc-i440fx-2.3'>hvm</type>
      <loader readonly='yes' type='pflash'>/usr/share/edk2.git/ovmf-x64/OVMF_CODE-pure-efi.fd</loader>
      <nvram template='/usr/share/edk2.git/ovmf-x64/OVMF_VARS-pure-efi.fd'>/var/lib/libvirt/qemu/nvram/Steam_VARS.fd</nvram>
    </os>
    <features>
      <acpi/>
      <apic/>
      <pae/>
      <kvm>
        <hidden state='on'/>
      </kvm>
    </features>
    <cpu mode='host-passthrough'>
      <topology sockets='1' cores='4' threads='1'/>
    </cpu>
    <clock offset='localtime'>
      <timer name='rtc' tickpolicy='catchup'/>
      <timer name='pit' tickpolicy='delay'/>
      <timer name='hpet' present='no'/>
    </clock>
    <on_poweroff>destroy</on_poweroff>
    <on_reboot>restart</on_reboot>
    <on_crash>restart</on_crash>
    <devices>
      <emulator>/usr/local/bin/qemu-system-x86_64</emulator>
      <disk type='file' device='disk'>
        <driver name='qemu' type='qcow2' cache='none' io='native'/>
        <source file='/mnt/store/vm/Steam.qcow2'/>
        <backingStore type='file' index='1'>
          <format type='raw'/>
          <source file='/mnt/store/vm/Steam.img'/>
          <backingStore/>
        </backingStore>
        <target dev='sda' bus='scsi'/>
        <boot order='2'/>
        <alias name='scsi0-0-0-0'/>
        <address type='drive' controller='0' bus='0' target='0' unit='0'/>
      </disk>
      <controller type='scsi' index='0' model='virtio-scsi'>
        <alias name='scsi0'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
      </controller>
      <controller type='usb' index='0' model='ich9-ehci1'>
        <alias name='usb0'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x7'/>
      </controller>
      <controller type='usb' index='0' model='ich9-uhci1'>
        <alias name='usb0'/>
        <master startport='0'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0' multifunction='on'/>
      </controller>
      <controller type='usb' index='0' model='ich9-uhci2'>
        <alias name='usb0'/>
        <master startport='2'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x1'/>
      </controller>
      <controller type='usb' index='0' model='ich9-uhci3'>
        <alias name='usb0'/>
        <master startport='4'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x2'/>
      </controller>
      <controller type='pci' index='0' model='pci-root'>
        <alias name='pci.0'/>
      </controller>
      <interface type='bridge'>
        <mac address='52:54:00:60:ef:ac'/>
        <source bridge='br0'/>
        <target dev='vnet0'/>
        <model type='virtio'/>
        <alias name='net0'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
      </interface>
      <hostdev mode='subsystem' type='pci' managed='yes'>
        <driver name='vfio'/>
        <source>
          <address domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
        </source>
        <alias name='hostdev0'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
      </hostdev>
      <hostdev mode='subsystem' type='pci' managed='yes'>
        <driver name='vfio'/>
        <source>
          <address domain='0x0000' bus='0x01' slot='0x00' function='0x1'/>
        </source>
        <alias name='hostdev1'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
      </hostdev>
      <memballoon model='none'>
        <alias name='balloon0'/>
      </memballoon>
    </devices>
    <qemu:commandline>
      <qemu:arg value='-snapshot'/>
    </qemu:commandline>
  </domain>

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