[Qemu-devel] [Bug 1563152] Re: general protection fault running VirtualBox in KVM guest

[Richard Hansen <1563152@bugs.launchpad.net>]

** Also affects: qemu (Ubuntu)
   Importance: Undecided
       Status: New

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https://bugs.launchpad.net/bugs/1563152

Title:
  general protection fault running VirtualBox in KVM guest

Status in QEMU:
  New
Status in qemu package in Ubuntu:
  New

Bug description:
  I'm trying to run nested VMs using qemu-kvm on the physical host and VirtualBox on the guest host:
    * physical host: Ubuntu 14.04 running Linux 4.2.0, qemu-kvm 2.0.0
    * guest host: Ubuntu 16.04 beta 2 running Linux 4.4.0, VirtualBox 5.0.16

  When I try to start up a VirtualBox VM in the guest host, I get a
  general protection fault (see below for dmesg output).  According to
  https://www.virtualbox.org/ticket/14965 this is caused by a bug in
  QEMU/KVM:

      The problem in more detail:  As written above, VirtualBox tries to
      read the MSR 0x9B (IA32_SMM_MONITOR_CTL).  This is an
      architectural MSR which is present if CPUID.01 / ECX bit 5 or bit
      6 are set (VMX or SMX).  As KVM has nested virtualization enabled
      and therefore pretends to support VT-x, this MSR must be
      accessible and reading from this MSR must not raise a
      #GP.  KVM/QEmu does not behave like real hardware in this case.

  dmesg output:

  SUPR0GipMap: fGetGipCpu=0x3
  general protection fault: 0000 [#1] SMP
  Modules linked in: pci_stub vboxpci(OE) vboxnetadp(OE) vboxnetflt(OE) vboxdrv(OE) xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack xt_tcpudp bridge stp llc iptable_filter ip_tables x_tables ppdev kvm_intel kvm irqbypass snd_hda_codec_generic snd_hda_intel snd_hda_codec snd_hda_core snd_hwdep snd_pcm snd_timer i2c_piix4 snd input_leds soundcore joydev 8250_fintek mac_hid serio_raw pvpanic parport_pc parport ib_iser rdma_cm iw_cm ib_cm ib_sa ib_mad ib_core ib_addr iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi autofs4 btrfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 multipath linear crct10dif_pclmul crc32_pclmul qxl ttm drm_kms_helper syscopyarea sysfillrect aesni_intel sysimgblt fb_sys_fops aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd psmouse floppy drm pata_acpi
  CPU: 0 PID: 31507 Comm: EMT Tainted: G           OE   4.4.0-15-generic #31-Ubuntu
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
  task: ffff880034c0a580 ti: ffff880002e00000 task.ti: ffff880002e00000
  RIP: 0010:[<ffffffffc067e506>]  [<ffffffffc067e506>] 0xffffffffc067e506
  RSP: 0018:ffff880002e03d70  EFLAGS: 00010206
  RAX: 00000000000006f0 RBX: 00000000ffffffdb RCX: 000000000000009b
  RDX: 0000000000000000 RSI: ffff880002e03d00 RDI: ffff880002e03cc8
  RBP: ffff880002e03d90 R08: 0000000000000004 R09: 00000000000006f0
  R10: 0000000049656e69 R11: 000000000f8bfbff R12: 0000000000000020
  R13: 0000000000000000 R14: ffffc9000057407c R15: ffffffffc0645260
  FS:  00007f89b8f6b700(0000) GS:ffff88007fc00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f89b8d10000 CR3: 0000000035ae1000 CR4: 00000000000006f0
  Stack:
   0000000000000000 ffffffff00000000 0000000000000000 0000000000000000
   ffff880002e03db0 ffffffffc0693e93 ffffc90000574010 ffff880035aae550
   ffff880002e03e30 ffffffffc060a3e7 ffff880002e03e10 0000000000000282
  Call Trace:
   [<ffffffffc060a3e7>] ? supdrvIOCtl+0x2de7/0x3250 [vboxdrv]
   [<ffffffffc06035b0>] ? VBoxDrvLinuxIOCtl_5_0_16+0x150/0x250 [vboxdrv]
   [<ffffffff8121e7df>] ? do_vfs_ioctl+0x29f/0x490
   [<ffffffff8106a554>] ? __do_page_fault+0x1b4/0x400
   [<ffffffff8121ea49>] ? SyS_ioctl+0x79/0x90
   [<ffffffff81821ff2>] ? entry_SYSCALL_64_fastpath+0x16/0x71
  Code: 88 e4 fc ff ff b9 3a 00 00 00 0f 32 48 c1 e2 20 89 c0 48 09 d0 48 89 05 f9 db 0e 00 0f 20 e0 b9 9b 00 00 00 48 89 05 d2 db 0e 00 <0f> 32 48 c1 e2 20 89 c0 b9 80 00 00 c0 48 09 d0 48 89 05 cb db
  RIP  [<ffffffffc067e506>] 0xffffffffc067e506
   RSP <ffff880002e03d70>
  ---[ end trace b3284b6520f49e0d ]---

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