From: Boris Ostrovsky boris.ostrovsky@oracle.com
[ Upstream commit c54b071c192dfe8061336f650ceaf358e6386e0b ]
Commit a926f81d2f6c ("xen/cpuhotplug: Replace cpu_up/down() with device_online/offline()") replaced cpu_down() with device_offline() call which requires that the CPU has been registered before. This registration, however, happens later from topology_init() which is called as subsys_initcall(). setup_vcpu_hotplug_event(), on the other hand, is invoked earlier, during arch_initcall().
As result, booting a PV(H) guest with vcpus < maxvcpus causes a crash.
Move setup_vcpu_hotplug_event() (and therefore setup_cpu_watcher()) to late_initcall(). In addition, instead of performing all offlining steps in setup_cpu_watcher() simply call disable_hotplug_cpu().
Fixes: a926f81d2f6c (xen/cpuhotplug: Replace cpu_up/down() with device_online/offline()" Signed-off-by: Boris Ostrovsky boris.ostrovsky@oracle.com Link: https://lore.kernel.org/r/1588976923-3667-1-git-send-email-boris.ostrovsky@o... Reviewed-by: Juergen Gross jgross@suse.com Signed-off-by: Boris Ostrovsky boris.ostrovsky@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/xen/cpu_hotplug.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/drivers/xen/cpu_hotplug.c b/drivers/xen/cpu_hotplug.c index ec975decb5de..b96b11e2b571 100644 --- a/drivers/xen/cpu_hotplug.c +++ b/drivers/xen/cpu_hotplug.c @@ -93,10 +93,8 @@ static int setup_cpu_watcher(struct notifier_block *notifier, (void)register_xenbus_watch(&cpu_watch);
for_each_possible_cpu(cpu) { - if (vcpu_online(cpu) == 0) { - device_offline(get_cpu_device(cpu)); - set_cpu_present(cpu, false); - } + if (vcpu_online(cpu) == 0) + disable_hotplug_cpu(cpu); }
return NOTIFY_DONE; @@ -119,5 +117,5 @@ static int __init setup_vcpu_hotplug_event(void) return 0; }
-arch_initcall(setup_vcpu_hotplug_event); +late_initcall(setup_vcpu_hotplug_event);