On 2015/1/7 23:44, Konrad Rzeszutek Wilk wrote:
> On Wed, Jan 07, 2015 at 11:37:52PM +0800, Jiang Liu wrote:
>> On 2015/1/7 22:50, Konrad Rzeszutek Wilk wrote:
>>> On Wed, Jan 07, 2015 at 02:13:49PM +0800, Jiang Liu wrote:
>>>> Commit b81975eade8c ("x86, irq: Clean up irqdomain transition code")
>>>> breaks xen IRQ allocation because xen_smp_prepare_cpus() doesn't invoke
>>>> setup_IO_APIC(), so no irqdomains created for IOAPICs and
>>>> mp_map_pin_to_irq() fails at the very beginning.
>>>> --- a/arch/x86/kernel/apic/io_apic.c
>>>> +++ b/arch/x86/kernel/apic/io_apic.c
>>>> @@ -2369,31 +2369,29 @@ static void ioapic_destroy_irqdomain(int idx)
>>>> ioapics[idx].pin_info = NULL;
>>>> }
>>>>
>>>> -void __init setup_IO_APIC(void)
>>>> +void __init setup_IO_APIC(bool xen_smp)
>>>> {
>>>> int ioapic;
>>>>
>>>> - /*
>>>> - * calling enable_IO_APIC() is moved to setup_local_APIC for BP
>>>> - */
>>>> - io_apic_irqs = nr_legacy_irqs() ? ~PIC_IRQS : ~0UL;
>>>> + if (!xen_smp) {
>>>> + apic_printk(APIC_VERBOSE, "ENABLING IO-APIC IRQs\n");
>>>> + io_apic_irqs = nr_legacy_irqs() ? ~PIC_IRQS : ~0UL;
>>>> +
>>>> + /* Set up IO-APIC IRQ routing. */
>>>> + x86_init.mpparse.setup_ioapic_ids();
>>>> + sync_Arb_IDs();
>>>> + }
Hi Konrad,
Enabling above code for Xen dom0 will cause following warning
because it writes a special value to ICR register.
[ 3.394981] ------------[ cut here ]------------
[ 3.394985] WARNING: CPU: 0 PID: 1 at arch/x86/xen/enlighten.c:968
xen_apic_write+0x15/0x20()
[ 3.394988] Modules linked in:
[ 3.394991] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.19.0-rc3+ #5
[ 3.394993] Hardware name: Dell Inc. OptiPlex 9020/0DNKMN, BIOS A03
09/17/2013
[ 3.394996] 00000000000003c8 ffff88003056bdd8 ffffffff817611bb
00000000000003c8
[ 3.395000] 0000000000000000 ffff88003056be18 ffffffff8106f4ea
0000000000000008
[ 3.395004] ffffffff81fc1120 ffff880030561348 000000000000a108
000000000000a101
[ 3.395008] Call Trace:
[ 3.395012] [<ffffffff817611bb>] dump_stack+0x4f/0x6c
[ 3.395015] [<ffffffff8106f4ea>] warn_slowpath_common+0xaa/0xd0
[ 3.395018] [<ffffffff8106f525>] warn_slowpath_null+0x15/0x20
[ 3.395021] [<ffffffff81003e25>] xen_apic_write+0x15/0x20
[ 3.395026] [<ffffffff81ef606b>] sync_Arb_IDs+0x84/0x86
[ 3.395029] [<ffffffff81ef7f7a>] setup_IO_APIC+0x7f/0x8e3
[ 3.395033] [<ffffffff810b275d>] ? trace_hardirqs_on+0xd/0x10
[ 3.395036] [<ffffffff8176858a>] ? _raw_spin_unlock_irqrestore+0x8a/0xa0
[ 3.395040] [<ffffffff81ee841b>] xen_smp_prepare_cpus+0x5d/0x184
[ 3.395044] [<ffffffff81ee1ba3>] kernel_init_freeable+0x149/0x293
[ 3.395047] [<ffffffff81758d49>] ? kernel_init+0x9/0xf0
[ 3.395049] [<ffffffff81758d40>] ? rest_init+0xd0/0xd0
[ 3.395052] [<ffffffff81758d49>] kernel_init+0x9/0xf0
[ 3.395054] [<ffffffff8176887c>] ret_from_fork+0x7c/0xb0
[ 3.395057] [<ffffffff81758d40>] ? rest_init+0xd0/0xd0
[ 3.395066] ---[ end trace 7c4371c8ba33d5d0 ]---
<snit>
>>>> ioapic_initialized = 1;
>>>> +
>>>> + if (!xen_smp) {
>>>> + init_IO_APIC_traps();
>>>> + if (nr_legacy_irqs())
>>>> + check_timer();
>>>> + }
>>>> }
And enabling above code causes Xen dom0 reboots.
Haven't test HVM and PV kernel yet.
So seems we still need special treatment for xen here.
Regards!
Gerry
>>>>
>>>> /*
>>>> diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
>>>> index 4c071aeb8417..7eb0283901fa 100644
>>>> --- a/arch/x86/xen/smp.c
>>>> +++ b/arch/x86/xen/smp.c
>>>> @@ -326,7 +326,10 @@ static void __init xen_smp_prepare_cpus(unsigned int max_cpus)
>>>>
>>>> xen_raw_printk(m);
>>>> panic(m);
>>>> + } else {
>>>> + setup_IO_APIC(true);
>>>> }
>>>> +
>>>> xen_init_lock_cpu(0);
>>>>
>>>> smp_store_boot_cpu_info();
>>>> --
>>>> 1.7.10.4
>>>>
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