Hi Thomas,
Sorry for the delay. I can confirm that the problem is fixed in 4.9.0-rc3 and prefill_possible_map no longer crashes (as it did in 4.9.0-rc2). Thank you!
Just a side question, is the previous fix in commit ff8560512b (x86/boot/smp: Don't try to poke disabled/non-existent APIC) actually still required or would the no-op APIC driver take care of it?
Regards,
Michal
----- Original Message -----
From: [email protected]
To: [email protected]
Cc: [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]
Sent: Friday, October 28, 2016 9:37:31 PM GMT +01:00 Amsterdam / Berlin / Bern / Rome / Stockholm / Vienna
Subject: Re: 4.8.2 not booting in 32-bit VM without I/O-APIC
On Fri, 28 Oct 2016, Thomas Gleixner wrote:
> On Fri, 28 Oct 2016, Michal Necasek wrote:
> >
> > Sorry if I wasn't clear. No, it doesn't work for us. The ff8560512b8d
> > commit fixes the APIC poking on machines where there is no local APIC
> > available (and thus fixes the committer's machine), but it doesn't work
> > in our case, where there is a local APIC but no I/O APIC, no ACPI MADT,
> > and no MP tables.
>
> > In other words, for us boot_cpu_has(X86_FEATURE_APIC) is true but the
> > APIC has not been set up yet because init_apic_mappings() hasn't been
> > run.
Right. That mapping setup is an utter trainwreck as we do it from multiple
places, but there is no reason why we can't move it before the call to
prefill_possible_map().
Thanks,
tglx
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index bbfbca5fea0c..b59fdba3cbdf 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1221,11 +1221,13 @@ void __init setup_arch(char **cmdline_p)
*/
get_smp_config();
+ /* Make sure apic is mapped before prefill_possible_map() */
+ init_apic_mappings();
+
prefill_possible_map();
init_cpu_to_node();
- init_apic_mappings();
io_apic_init_mappings();
kvm_guest_init();
Hello,
On 03.11.2016 21:02, Michal Necasek wrote:
> Sorry for the delay. I can confirm that the problem is fixed in
> 4.9.0-rc3 and prefill_possible_map no longer crashes (as it did in
> 4.9.0-rc2). Thank you!
>
> Just a side question, is the previous fix in commit ff8560512b
> (x86/boot/smp: Don't try to poke disabled/non-existent APIC) actually
> still required or would the no-op APIC driver take care of it?
Sorry for the delay too (holiday-related). I tested 4.9.0rc4 on a
32-bit VirtualBox virtual machine without I/O-APIC and can confirm that
it now boots. Since I am at it, the OHCI timer wheel-related problems
are also no longer reproducible.
Regards and thanks,
Michael
>
> Regards, Michal
>
> ----- Original Message ----- From: [email protected] To:
> [email protected] Cc: [email protected],
> [email protected], [email protected],
> [email protected], [email protected],
> [email protected] Sent: Friday, October 28, 2016 9:37:31
> PM GMT +01:00 Amsterdam / Berlin / Bern / Rome / Stockholm / Vienna
> Subject: Re: 4.8.2 not booting in 32-bit VM without I/O-APIC
>
> On Fri, 28 Oct 2016, Thomas Gleixner wrote:
>
>> On Fri, 28 Oct 2016, Michal Necasek wrote:
>>>
>>> Sorry if I wasn't clear. No, it doesn't work for us. The
>>> ff8560512b8d commit fixes the APIC poking on machines where there
>>> is no local APIC available (and thus fixes the committer's
>>> machine), but it doesn't work in our case, where there is a local
>>> APIC but no I/O APIC, no ACPI MADT, and no MP tables.
>>
>>> In other words, for us boot_cpu_has(X86_FEATURE_APIC) is true but
>>> the APIC has not been set up yet because init_apic_mappings()
>>> hasn't been run.
>
> Right. That mapping setup is an utter trainwreck as we do it from
> multiple places, but there is no reason why we can't move it before
> the call to prefill_possible_map().
>
> Thanks,
>
> tglx
>
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index
> bbfbca5fea0c..b59fdba3cbdf 100644 --- a/arch/x86/kernel/setup.c +++
> b/arch/x86/kernel/setup.c @@ -1221,11 +1221,13 @@ void __init
> setup_arch(char **cmdline_p) */ get_smp_config();
>
> + /* Make sure apic is mapped before prefill_possible_map() */ +
> init_apic_mappings(); + prefill_possible_map();
>
> init_cpu_to_node();
>
> - init_apic_mappings(); io_apic_init_mappings();
>
> kvm_guest_init();
>
--
Michael Thayer | VirtualBox engineer
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On Thu, 10 Nov 2016, Michael Thayer wrote:
> On 03.11.2016 21:02, Michal Necasek wrote:
> > Sorry for the delay. I can confirm that the problem is fixed in
> > 4.9.0-rc3 and prefill_possible_map no longer crashes (as it did in
> > 4.9.0-rc2). Thank you!
> >
> > Just a side question, is the previous fix in commit ff8560512b
> > (x86/boot/smp: Don't try to poke disabled/non-existent APIC) actually
> > still required or would the no-op APIC driver take care of it?
>
> Sorry for the delay too (holiday-related). I tested 4.9.0rc4 on a 32-bit
No problem. I hope you enjoyed your well earned vacation :)
> VirtualBox virtual machine without I/O-APIC and can confirm that it now boots.
> Since I am at it, the OHCI timer wheel-related problems are also no longer
> reproducible.
Thanks for reporting back!
tglx