[Bug 1885175] Re: memory.c range assertion hit at full invalidating

[Eugenio Pérez]

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

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https://bugs.launchpad.net/bugs/1885175

Title:
  memory.c range assertion hit at full invalidating

Status in QEMU:
  Fix Released

Bug description:
  I am able to hit this assertion when a Red Hat 7 guest virtio_net
  device raises an "Invalidation" of all the TLB entries. This happens
  in the guest's startup if 'intel_iommu=on' argument is passed to the
  guest kernel and right IOMMU/ATS devices are declared in qemu's
  command line.

  Command line: /home/qemu/x86_64-softmmu/qemu-system-x86_64 -name
  guest=rhel7-test,debug-threads=on -machine
  pc-q35-5.1,accel=kvm,usb=off,dump-guest-core=off,kernel_irqchip=split
  -cpu
  Broadwell,vme=on,ss=on,vmx=on,f16c=on,rdrand=on,hypervisor=on,arat=on
  ,tsc-adjust=on,umip=on,arch-
  capabilities=on,xsaveopt=on,pdpe1gb=on,abm=on,skip-l1dfl-
  vmentry=on,rtm=on,hle=on -m 8096 -realtime mlock=off -smp
  2,sockets=2,cores=1,threads=1 -uuid d022ecbf-679e-4755-87ce-
  eb87fc5bbc5d -display none -no-user-config -nodefaults -rtc
  base=utc,driftfix=slew -global kvm-pit.lost_tick_policy=delay -no-hpet
  -no-shutdown -global ICH9-LPC.disable_s3=1 -global
  ICH9-LPC.disable_s4=1 -boot strict=on -device intel-iommu,intremap=on
  ,device-iotlb=on -device pcie-root-
  port,port=0x8,chassis=1,id=pci.1,bus=pcie.0,multifunction=on,addr=0x1
  -device pcie-root-
  port,port=0x9,chassis=2,id=pci.2,bus=pcie.0,addr=0x1.0x1 -device pcie-
  root-port,port=0xa,chassis=3,id=pci.3,bus=pcie.0,addr=0x1.0x2 -device
  pcie-root-port,port=0xb,chassis=4,id=pci.4,bus=pcie.0,addr=0x1.0x3
  -device pcie-root-
  port,port=0xc,chassis=5,id=pci.5,bus=pcie.0,addr=0x1.0x4 -device pcie-
  root-port,port=0xd,chassis=6,id=pci.6,bus=pcie.0,addr=0x1.0x5 -device
  pcie-root-port,port=0xe,chassis=7,id=pci.7,bus=pcie.0,addr=0x1.0x6
  -device qemu-xhci,p2=15,p3=15,id=usb,bus=pci.2,addr=0x0 -device
  virtio-serial-pci,id=virtio-serial0,bus=pci.3,addr=0x0 -drive
  file=/home/virtio-test2.qcow2,format=qcow2,if=none,id=drive-virtio-
  disk0 -device virtio-blk-pci,scsi=off,bus=pci.4,addr=0x0,drive=drive-
  virtio-disk0,id=virtio-disk0,bootindex=1 -netdev
  tap,id=hostnet0,vhost=on,vhostforce=on -device virtio-net-
  
pci,netdev=hostnet0,id=net0,mac=52:54:00:0d:1d:f2,bus=pci.1,addr=0x0,iommu_platform=on,ats=on
  -device virtio-balloon-pci,id=balloon0,bus=pci.5,addr=0x0 -object rng-
  random,id=objrng0,filename=/dev/urandom -device virtio-rng-
  pci,rng=objrng0,id=rng0,bus=pci.6,addr=0x0 -s -msg timestamp=on

  Full backtrace:

  #0  0x00007ffff521370f in raise () at /lib64/libc.so.6
  #1  0x00007ffff51fdb25 in abort () at /lib64/libc.so.6
  #2  0x00007ffff51fd9f9 in _nl_load_domain.cold.0 () at /lib64/libc.so.6
  #3  0x00007ffff520bcc6 in .annobin_assert.c_end () at /lib64/libc.so.6
  #4  0x0000555555888171 in memory_region_notify_one (notifier=0x7ffde05dfde8, 
entry=0x7ffde5dfe200) at /home/qemu/memory.c:1918
  #5  0x0000555555888247 in memory_region_notify_iommu 
(iommu_mr=0x555556f6c0b0, iommu_idx=0, entry=...) at /home/qemu/memory.c:1941
  #6  0x0000555555951c8d in vtd_process_device_iotlb_desc (s=0x555557609000, 
inv_desc=0x7ffde5dfe2d0)
      at /home/qemu/hw/i386/intel_iommu.c:2468
  #7  0x0000555555951e6a in vtd_process_inv_desc (s=0x555557609000) at 
/home/qemu/hw/i386/intel_iommu.c:2531
  #8  0x0000555555951fa5 in vtd_fetch_inv_desc (s=0x555557609000) at 
/home/qemu/hw/i386/intel_iommu.c:2563
  #9  0x00005555559520e5 in vtd_handle_iqt_write (s=0x555557609000) at 
/home/qemu/hw/i386/intel_iommu.c:2590
  #10 0x0000555555952b45 in vtd_mem_write (opaque=0x555557609000, addr=136, 
val=2688, size=4) at /home/qemu/hw/i386/intel_iommu.c:2837
  #11 0x0000555555883e17 in memory_region_write_accessor
      (mr=0x555557609330, addr=136, value=0x7ffde5dfe478, size=4, shift=0, 
mask=4294967295, attrs=...) at /home/qemu/memory.c:483
  #12 0x000055555588401d in access_with_adjusted_size
      (addr=136, value=0x7ffde5dfe478, size=4, access_size_min=4, 
access_size_max=8, access_fn=
      0x555555883d38 <memory_region_write_accessor>, mr=0x555557609330, 
attrs=...) at /home/qemu/memory.c:544
  #13 0x0000555555886f37 in memory_region_dispatch_write (mr=0x555557609330, 
addr=136, data=2688, op=MO_32, attrs=...)
      at /home/qemu/memory.c:1476
  #14 0x0000555555827a03 in flatview_write_continue
      (fv=0x7ffde00935d0, addr=4275634312, attrs=..., ptr=0x7ffff7ff0028, 
len=4, addr1=136, l=4, mr=0x555557609330) at /home/qemu/exec.c:3146
  #15 0x0000555555827b48 in flatview_write (fv=0x7ffde00935d0, addr=4275634312, 
attrs=..., buf=0x7ffff7ff0028, len=4)
      at /home/qemu/exec.c:3186
  #16 0x0000555555827e9d in address_space_write
      (as=0x5555567ca640 <address_space_memory>, addr=4275634312, attrs=..., 
buf=0x7ffff7ff0028, len=4) at /home/qemu/exec.c:3277
  #17 0x0000555555827f0a in address_space_rw
      (as=0x5555567ca640 <address_space_memory>, addr=4275634312, attrs=..., 
buf=0x7ffff7ff0028, len=4, is_write=true)
      at /home/qemu/exec.c:3287
  #18 0x000055555589b633 in kvm_cpu_exec (cpu=0x555556b65640) at 
/home/qemu/accel/kvm/kvm-all.c:2511
  #19 0x0000555555876ba8 in qemu_kvm_cpu_thread_fn (arg=0x555556b65640) at 
/home/qemu/cpus.c:1284
  #20 0x0000555555dafff1 in qemu_thread_start (args=0x555556b8c3b0) at 
util/qemu-thread-posix.c:521
  #21 0x00007ffff55a62de in start_thread () at /lib64/libpthread.so.0
  #22 0x00007ffff52d7e83 in clone () at /lib64/libc.so.6

  --

  If we examinate *entry in frame 4 of backtrace:
  *entry = {target_as = 0x555556f6c050, iova = 0x0, translated_addr = 0x0, 
addr_mask = 0xffffffffffffffff, perm = 0x0}

  Which (I think) tries to invalidate all the TLB registers of the
  device.

  Just deleting that assert is enough for the VM to start and
  communicate using IOMMU, but maybe a better alternative is possible.
  We could move it to the caller functions in other cases than IOMMU
  invalidation, or make it conditional only if not invalidating.

  Guest kernel version: kernel-3.10.0-1151.el7.x86_64

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