On Fri, Feb 27, 2015 at 12:19 PM, Steven Rostedt <[email protected]> wrote: > On Fri, 27 Feb 2015 11:53:39 -0800 > Andy Lutomirski <[email protected]> wrote: > >> This is embarrassing. I must have gotten lucky testing it. >> > > The thing is, it booted fine on all my tests. It wasn't until I did > hotplug where it crashed. > > I'm not sure what's in CR4 when the CPU comes up, but perhaps zero is > fine to start out and the writes to CR4 update makes the shadow and reg > the same. It's when we hotplug that the two become out of sync. >
I bet that having the shadow set to zero is fine because the first attempt to set a bit in cr4 will clear all the other bits without harmful side effects. But if the shadow starts out at 0xffffffff or something like that, then the early attempts to set bits will have no effect and we'll fail. --Andy > Just my theory. > > -- Steve -- Andy Lutomirski AMA Capital Management, LLC -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
