On Tue, Jun 30, 2009 at 11:43:41AM -0700, Yinghai Lu wrote: > 2009/6/30 Gleb Natapov <gleb@xxxxxxxxxx>: > > >> > >> how about kexec second kernel in KVM ? > >> > >> x2apic_preenabled will be set in second kernel. > >> > > Yes, bummer. But the similar problem exist now and without KVM. After > > running x2apic enabled kernel you can't kexec kernel without x2apic > > support. > > if the first kernel enable x2apic and intr_remapping, and second > kernel has x2apic and intr_remap support. > we can kexec the second kernel. > And if it hasn't we cannot, that is what I am trying to point out. > restoring to original state is not possible for kdump case. > Shouldn't it be enough to run UP kernel for kdump? So kdump can reset BSP apic to xAPIC mode before starting a kernel with maxcpus=1. > maybe with minor change to your patch, you could kexec the in kexec > second kernel with x2apic support. > My patch can easily avoid the issue by checking max_physical_apicid > 255 instead of x2apic_preenabled. -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
