On Wed, Nov 05, 2008 at 11:27:32PM +0100, Pavel Machek wrote: > On Wed 2008-11-05 17:56:52, Eduardo Habkost wrote: > > This patch adds an interface to set a function that can be used to > > disable virtualization extensions on the CPU on emergency cases, such > > as on kdump or emergency reboot. > > > > The function will be set by code that enables virtualization extensions > > on the CPUs (i.e. KVM), and should do the very least to disable virt > > extensions on the CPU where it is being called. > > > > The functions that set the function pointer uses RCU synchronization, > > just in case the crash NMI is triggered while KVM is unloading. > > > > We can't just use the same notifiers used at reboot time (that are used > > by non-crash-dump kexec), because at crash time some CPUs may have IRQs > > disabled, so we can't use IPIs. The crash shutdown code use NMIs to tell > > the other CPUs to be halted, so the notifier call will be hooked into > > the CPU halting code that is on the crash shutdown NMI handler. > > > > [v2: drop 'unsigned int cpu' arg from function] > > [v3: make emergency_virt_disable() non-static] > > [v4: add a config option for it: CPU_VIRT_EXTENSIONS] > > [v5: add has_virt_extensions() function] > > [v6: don't define the registering functions if CPU_VIRT_EXTENSIONS is > > not enabled] > > [v7: use EXPORT_SYMBOL_GPL] > > > > > --- /dev/null > > +++ b/arch/x86/kernel/virtext.c > > @@ -0,0 +1,89 @@ > > +/* Core CPU virtualization extensions handling > > + * > > + * This should carry the code for handling CPU virtualization extensions > > + * that needs to live in the kernel core. > > + * > > + * Author: Eduardo Habkost <ehabkost at redhat.com> > > + * > > + * Copyright (C) 2008, Red Hat Inc. > > + */ > > GPL? Yes, of course. As IANAL, I used a similar .c file as reference for the author/copyright info header, and used arch/x86/kernel/crash.c, that doesn't refer to the GPL also. I think I chose a bad example as reference. arch/x86/kernel/crash.c even has "All rights reserved". Ouch. -- Eduardo
