On Mon, Oct 27, 2008 at 10:54:01AM +0200, Avi Kivity wrote: > Eduardo Habkost wrote: >>> (we can use NMI IPIs, but that will likely be messy) >>> >> >> NMI IPIs are already used on x86 native_machine_crash_shutdown(), so >> it wouldn't get more messy that it is currently. We just need to add >> another bit of code to the code that already runs on an NMI handler. >> >> > > That looks like the easiest (and best) way out. > >> My question is: is a notifier chain too much complexity for a sensible >> piece of code like that? If so, a compile-time hook on that point >> would be safer, > > I think an unconditional vmx disable is wanted here, so kexec can work > with other hypervisors. > >> but then it wouldn't work when KVM is compiled as a >> out-of-tree module. >> > > The external module can do without. It's possible to hijack the nmi > vector, but I don't think that's a good idea. If someone wants > kexec+vmx on an older kernel, they can patch that kernel. > >>> But what happens when the kdump kernel reboots? If it is >>> uniprocessor, it will never have a chance to disable vmx on other >>> cpus. Using acpi reset (now default) works around this on some >>> machines, but not all. >>> >> Good point. My problem was a hang when booting the kdump kernel, but it >> may also cause problems later, when the kdump kernel reboots. >> > > The hang was likely caused by vmx blocking INIT. Sigh. Avi, We boot kdump kernel with maxcpus=1. IIUC, in that code path we will not be using INIT. So did you try booting kdump kernel with maxcpus=1 and did it work for you? If not than problem could be something else. Thanks Vivek > > -- > error compiling committee.c: too many arguments to function
