Hi, I observe a regression on KVM accelerated qemu-system-aarch64:
Unexpected error in kvm_device_access() at /home/augere/UPSTREAM/qemu/accel/kvm/kvm-all.c:2164: 2018-03-23T09:59:59.629439Z qemu-system-aarch64: KVM_GET_DEVICE_ATTR failed: Group 6 attr 0x000000000000c664: Device or resource busy 2018-03-23 10:00:00.085+0000: shutting down, reason=crashed I did a bisect and it looks the commit that introduces the regression is " commit 3fd2457d18edf5736f713dfe1ada9c87a9badab1 Author: Peter Xu <pet...@redhat.com> Date: Fri Mar 9 17:00:03 2018 +0800 monitor: enable IO thread for (qmp & !mux) typed Start to use dedicate IO thread for QMP monitors that are not using MUXed chardev. Reviewed-by: Fam Zheng <f...@redhat.com> Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com> Signed-off-by: Peter Xu <pet...@redhat.com> Message-Id: <20180309090006.10018-21-pet...@redhat.com> Signed-off-by: Eric Blake <ebl...@redhat.com> " If reverted on top of v2.12.0-rc0, the guest boots fine again. The link is not obvious though. Thanks Eric