From d1038b12072b0925db1deb973ce3b06e0a718143 Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Tue, 7 Feb 2012 19:11:51 -0500 Subject: [PATCH] xen/cpu: Make VCPU hotplug code online CPUs properly. Offlining CPUs works. Onlining does not work anymore and it looks like we were missing a cpu_up() call in the hotplug bring up path. When the vCPUs are initialized, if they are onlined or never had been in use (so maxcpus > vcpus) the vCPUs are in xen_play_dead having called VCPUOP_down and are not running. When a vCPU is onlined, the bootup (or any other currently running CPU) is suppose to call VCPUOP_up on the vCPU that is not running and make the vCPU unhinge itself out of the xen_play_dead and continue in cpu_idle. We did not make the hypercall on onlining, nor did we recreate the timer, spinlocks, ipi interrupts so the vCPU never was onlined. This patch fixes it by calling cpu_on() and we also make the code more readable. Signed-off-by: Konrad Rzeszutek Wilk --- drivers/xen/cpu_hotplug.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/drivers/xen/cpu_hotplug.c b/drivers/xen/cpu_hotplug.c index 4dcfced107f5..df80af818d5f 100644 --- a/drivers/xen/cpu_hotplug.c +++ b/drivers/xen/cpu_hotplug.c @@ -8,18 +8,20 @@ static void enable_hotplug_cpu(int cpu) { - if (!cpu_present(cpu)) + if (!cpu_present(cpu)) { arch_register_cpu(cpu); - - set_cpu_present(cpu, true); + set_cpu_present(cpu, true); + (void)cpu_up(cpu); + } } static void disable_hotplug_cpu(int cpu) { - if (cpu_present(cpu)) + if (cpu_present(cpu)) { + (void)cpu_down(cpu); + set_cpu_present(cpu, false); arch_unregister_cpu(cpu); - - set_cpu_present(cpu, false); + } } static int vcpu_online(unsigned int cpu) @@ -53,7 +55,6 @@ static void vcpu_hotplug(unsigned int cpu) enable_hotplug_cpu(cpu); break; case 0: - (void)cpu_down(cpu); disable_hotplug_cpu(cpu); break; default: -- 2.39.5