[patch v3 16/36] x86/xen/smp_pv: Remove wait for CPU online

Thomas Gleixner
2023-05-08T19:44:54Z

From: Thomas Gleixner <tglx@linutronix.de>

Now that the core code drops sparse_irq_lock after the idle thread
synchronized, it's pointless to wait for the AP to mark itself online.

Whether the control CPU runs in a wait loop or sleeps in the core code
waiting for the online operation to complete makes no difference.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mikelley@microsoft.com>

---
arch/x86/xen/smp_pv.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
---

--- a/arch/x86/xen/smp_pv.c
+++ b/arch/x86/xen/smp_pv.c
@@ -340,11 +340,11 @@ static int xen_pv_cpu_up(unsigned int cp

xen_pmu_init(cpu);

- rc = HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL);
- BUG_ON(rc);
-
- while (cpu_report_state(cpu) != CPU_ONLINE)
- HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
+ /*
+ * Why is this a BUG? If the hypercall fails then everything can be
+ * rolled back, no?
+ */
+ BUG_ON(HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL));

return 0;
}