Greetings,

FYI, I got lots of these errors in 3.6.0 in one of my test box.
Attached is the full dmesg.

[ 5174.699117] vmwrite error: reg 401e value 81e76200 (err 12)
[ 5174.701692] vmwrite error: reg 401e value 81e76200 (err 12)
[ 5174.701696] Pid: 3948, comm: kvm Not tainted 3.6.0 #23
[ 5174.701696] Call Trace:
[ 5174.701708]  [<ffffffff8195f111>] vmwrite_error+0x2c/0x2e
[ 5174.701713]  [<ffffffff8102e419>] vmcs_writel+0x1e/0x20
[ 5174.701716]  [<ffffffff8102f8fa>] vmx_cpuid_update+0xe4/0xf8
[ 5174.701719]  [<ffffffff8102cc9a>] kvm_vcpu_ioctl_set_cpuid2+0x68/0x7d
[ 5174.701723]  [<ffffffff81013aeb>] kvm_arch_vcpu_ioctl+0x34f/0xc55
[ 5174.701725]  [<ffffffff8102f9c2>] ? vmx_vcpu_load+0x33/0x195
[ 5174.701727]  [<ffffffff810136eb>] ? kvm_arch_vcpu_load+0xb9/0x16a
[ 5174.701730]  [<ffffffff81004916>] kvm_vcpu_ioctl+0x46c/0x4ea
[ 5174.701732]  [<ffffffff81013617>] ? kvm_arch_dev_ioctl+0x16d/0x188
[ 5174.701736]  [<ffffffff81157b8f>] do_vfs_ioctl+0x462/0x4a3
[ 5174.701740]  [<ffffffff8111c408>] ? vm_mmap_pgoff+0x6b/0x78
[ 5174.701742]  [<ffffffff81157c17>] sys_ioctl+0x47/0x6c
[ 5174.701746]  [<ffffffff81978ba9>] system_call_fastpath+0x16/0x1b
[ 5174.702587] vmwrite error: reg 401e value 81e76200 (err 12)
[ 5174.702589] Pid: 3947, comm: kvm Not tainted 3.6.0 #23
[ 5174.702589] Call Trace:
[ 5174.702594]  [<ffffffff8195f111>] vmwrite_error+0x2c/0x2e
[ 5174.702597]  [<ffffffff8102e419>] vmcs_writel+0x1e/0x20
[ 5174.702599]  [<ffffffff8102f8fa>] vmx_cpuid_update+0xe4/0xf8
[ 5174.702601]  [<ffffffff8102cc9a>] kvm_vcpu_ioctl_set_cpuid2+0x68/0x7d
[ 5174.702603]  [<ffffffff81013aeb>] kvm_arch_vcpu_ioctl+0x34f/0xc55
[ 5174.702606]  [<ffffffff8102f9c2>] ? vmx_vcpu_load+0x33/0x195
[ 5174.702608]  [<ffffffff810136eb>] ? kvm_arch_vcpu_load+0xb9/0x16a
[ 5174.702609]  [<ffffffff81004916>] kvm_vcpu_ioctl+0x46c/0x4ea
[ 5174.702611]  [<ffffffff81013617>] ? kvm_arch_dev_ioctl+0x16d/0x188
[ 5174.702614]  [<ffffffff81157b8f>] do_vfs_ioctl+0x462/0x4a3
[ 5174.702616]  [<ffffffff8111c408>] ? vm_mmap_pgoff+0x6b/0x78
[ 5174.702617]  [<ffffffff81157c17>] sys_ioctl+0x47/0x6c
[ 5174.702620]  [<ffffffff81978ba9>] system_call_fastpath+0x16/0x1b

Another test box running the same kernel hangs and keep emitting the
following dmesg lines:

vmx_handle_exit: unexpected, valid vectoring info (0x80000b0e) and
exit reason is 0x31

Thanks,
Fengguang