Comment 33 for bug 1561019

This still happens with Fedora 19, libvirt-1.0.5.5-1.fc19.x86_64.

Loading the btrfs module, which loads the xor module, fails
because it tries to run an AVX instruction:

modprobe btrfs
[ 1.804591] xor: automatically using best checksumming function:
[ 1.806020] invalid opcode: 0000 [#1] SMP
[ 1.806416] Modules linked in: xor(+) snd_pcsp snd_pcm snd_page_alloc ghash_clmulni_intel snd_timer microcode snd soundcore virtio_net virtio_scsi virtio_blk virtio_rng virtio_balloon virtio_mmio sparse_keymap rfkill sym53c8xx scsi_transport_spi crc8 crc_ccitt crc32 crc_itu_t crc32_pclmul crc32c_intel libcrc32c megaraid megaraid_sas megaraid_mbox megaraid_mm
[ 1.809709] CPU: 0 PID: 150 Comm: modprobe Not tainted 3.10.9-200.fc19.x86_64.debug #1
[ 1.810397] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 1.810931] task: ffff880019cf8000 ti: ffff880019ca4000 task.ti: ffff880019ca4000
[ 1.811597] RIP: 0010:[<ffffffffa0119da0>] [<ffffffffa0119da0>] xor_avx_2+0x50/0x230 [xor]
[ 1.812333] RSP: 0018:ffff880019ca5d08 EFLAGS: 00010202
[ 1.812811] RAX: 0000000000000007 RBX: ffff880019eb8000 RCX: ffff880019cf8000
[ 1.813429] RDX: ffff880019ca5fd8 RSI: 0000000000000000 RDI: 0000000000001000
[ 1.814071] RBP: ffff880019ca5d20 R08: 0000000000000002 R09: 0000000000000000
[ 1.814684] R10: 0000000000000001 R11: 0000000000000001 R12: ffff880019ebb000
[ 1.815320] R13: 0000000000000008 R14: ffff880019eb8000 R15: 00000000fffb732e
[ 1.815952] FS: 00007fb93b96a740(0000) GS:ffff88001f000000(0000) knlGS:0000000000000000
[ 1.816647] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1.817170] CR2: 00007f8d740e9000 CR3: 0000000019e2b000 CR4: 00000000000007f0
[ 1.817785] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1.818424] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 1.819047] Stack:
[ 1.819245] 0000000000000000 ffffffffa011c000 ffff880019ebb000 ffff880019ca5d60
[ 1.819929] ffffffffa00a7080 0000000000000005 ffff880019eb8000 ffff880019ebb000
[ 1.820651] ffffffffa011c110 0000000000000001 ffffffffa011c0c0 ffff880019ca5d80
[ 1.821354] Call Trace:
[ 1.821581] [<ffffffffa00a7080>] do_xor_speed+0x80/0xe0 [xor]
[ 1.822097] [<ffffffffa00a714b>] calibrate_xor_blocks+0x6b/0xf20 [xor]
[ 1.822683] [<ffffffffa00a70e0>] ? do_xor_speed+0xe0/0xe0 [xor]
[ 1.823214] [<ffffffff810020e2>] do_one_initcall+0xe2/0x1a0
[ 1.823723] [<ffffffff810e95e2>] load_module+0x1c62/0x27d0
[ 1.824217] [<ffffffff813749d0>] ? ddebug_proc_write+0xf0/0xf0
[ 1.824748] [<ffffffff810ea2e6>] SyS_finit_module+0x86/0xb0
[ 1.825247] [<ffffffff81720099>] system_call_fastpath+0x16/0x1b
[ 1.825779] Code: 01 00 00 65 48 8b 04 25 f0 c8 00 00 83 80 44 e0 ff ff 01 e8 23 7a f0 e0 4d 85 ed 49 8d 45 ff 0f 84 9b 01 00 00 66 0f 1f 44 00 00 <c4> c1 7d 6f 04 24 c5 fc 57 03 c5 fd 7f 03 c4 c1 7d 6f 4c 24 20
[ 1.828335] RIP [<ffffffffa0119da0>] xor_avx_2+0x50/0x230 [xor]
[ 1.828869] RSP <ffff880019ca5d08>
[ 1.829213] ---[ end trace 70ce68c981f09edb ]---

However using plain old -cpu host on the qemu command line works fine.