On Wed, Jul 27, 2016 at 08:22:51AM +0530, Bharata B Rao wrote: > Hi, > > Coalesced mmio buffer is part of vCPU 0's kvm_run mmap'ed area > and with the introduction of CPU hotplug, vCPU 0 can be removed on > PowerPC leading to the below seen segfault in QEMU. > > > This happens because during CPU removal, though we park the kvm_fd > corresponding to the removed vCPU thread, we unmap the kvm_run (and > hence coalesced mmio ring). > <snip> > What would be the best way to fix this ? Is disassociating coalesced_mmio_ring > from vCPU 0's kvm_run the correct solution ?
May be PowerPC too should do what x86 does like below for now ? commit 73360e27850b213327011f7e22e03865b8c0dd5b Author: Igor Mammedov <imamm...@redhat.com> Date: Mon Jul 18 10:31:22 2016 +0200 pc: Forbid BSP removal Boot CPU is assumed to always present in QEMU code, so untile that assumptions are gone, deny removal request, In another words QEMU won't support BSP hot-unplug.