Commit 2de7fd26 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Peter Zijlstra
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x86/xen/smp_pv: Remove wait for CPU online 



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: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: default avatarMichael Kelley <mikelley@microsoft.com>
Tested-by: default avatarOleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205256.369512093@linutronix.de
parent e464640c

arch/x86/xen/smp_pv.c

+5 −5
Original line number Diff line number Diff line
@@ -340,11 +340,11 @@ static int xen_pv_cpu_up(unsigned int cpu, struct task_struct *idle) 


	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;

}