Comment 7 for bug 445456

Thanks a lot for the tedious bisect. So it seems this gets down to something around 64bit mode. If I read the code correctly, the old version (for a i386 guest calling vmx_set_msr() to modify the extended feature enable register) went into the default case which directly modified the msr data and then called kvm_set_msr_common(), while the code that hangs, does not do that. I will do a debug version, which traces the codepath better and post a link to it here later.