On 4/14/23 7:44 PM, Thomas Gleixner wrote:
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
Cc: Juergen Gross
Cc: Boris Ostrovsky
Cc: xen-devel@lists.xenproject.org
---
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?
+*/
In many cases this indicates either some sort of hypervisor internal error or
broken logic in the guest, so it is, well, a bug. But I suppose it may also be
some transient condition in the hypervisor (I don't see it now but it can
happen in the future) so perhaps we should indeed try not to die on the spot.
-boris
+ BUG_ON(HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL));
return 0;
}
