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Groups > linux.kernel > #1373986
| From | Juergen Gross <jgross@suse.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v4 04/14] x86/rtc: replace paravirt rtc check with platform legacy quirk |
| Date | 2016-04-08 07:20 +0200 |
| Message-ID | <rlwZQ-7ow-5@gated-at.bofh.it> (permalink) |
| References | <rl5Gh-3Ao-3@gated-at.bofh.it> <rl5Gi-3Ao-17@gated-at.bofh.it> <rlhHs-3TE-21@gated-at.bofh.it> <rlsCT-3LP-27@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 08/04/16 02:32, Luis R. Rodriguez wrote:
> On Thu, Apr 07, 2016 at 08:55:54AM -0400, Boris Ostrovsky wrote:
>> On 04/06/2016 08:06 PM, Luis R. Rodriguez wrote:
>>> We have 4 types of x86 platforms that disable RTC:
>>>
>>> * Intel MID
>>> * Lguest - uses paravirt
>>> * Xen dom-U - uses paravirt
>>> * x86 on legacy systems annotated with an ACPI legacy flag
>>>
>>> We can consolidate all of these into a platform specific legacy
>>> quirk set early in boot through i386_start_kernel() and through
>>> x86_64_start_reservations(). This deals with the RTC quirks which
>>> we can rely on through the hardware subarch, the ACPI check can
>>> be dealt with separately.
>>>
>>> v2: split the subarch check from the ACPI check, clarify
>>> on the ACPI change commit log why ordering works
>>>
>>> Suggested-by: Ingo Molnar <mingo@kernel.org>
>>> Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
>
> <-- snip -->
>
>>> diff --git a/arch/x86/kernel/platform-quirks.c b/arch/x86/kernel/platform-quirks.c
>>> new file mode 100644
>>> index 000000000000..1b114ac5996f
>>> --- /dev/null
>>> +++ b/arch/x86/kernel/platform-quirks.c
>>> @@ -0,0 +1,18 @@
>>> +#include <linux/kernel.h>
>>> +#include <linux/init.h>
>>> +
>>> +#include <asm/setup.h>
>>> +#include <asm/bios_ebda.h>
>>> +
>>> +void __init x86_early_init_platform_quirks(void)
>>> +{
>>> + x86_platform.legacy.rtc = 1;
>>> +
>>> + switch (boot_params.hdr.hardware_subarch) {
>>> + case X86_SUBARCH_XEN:
>>> + case X86_SUBARCH_LGUEST:
>>> + case X86_SUBARCH_INTEL_MID:
>>> + x86_platform.legacy.rtc = 0;
>>> + break;
>>> + }
>>> +}
>>
>> What about Xen dom0 (aka initial domain)?
>
> Indeed, thanks for catching this, the hunk below removes the re-enablement of
> the the RTC for dom0:
>
>>> --- a/arch/x86/xen/enlighten.c
>>> +++ b/arch/x86/xen/enlighten.c
>>> @@ -1192,7 +1192,6 @@ static const struct pv_info xen_info __initconst = {
>>> #ifdef CONFIG_X86_64
>>> .extra_user_64bit_cs = FLAT_USER_CS64,
>>> #endif
>>> - .features = 0,
>>> .name = "Xen",
>>> };
>>> @@ -1525,8 +1524,6 @@ asmlinkage __visible void __init xen_start_kernel(void)
>>> /* Install Xen paravirt ops */
>>> pv_info = xen_info;
>>> - if (xen_initial_domain())
>>> - pv_info.features |= PV_SUPPORTED_RTC;
>>> pv_init_ops = xen_init_ops;
>>> if (!xen_pvh_domain()) {
>>> pv_cpu_ops = xen_cpu_ops;
>
> This should then break dom0 unless of course you have the respective next
> patch applied and that disabled the RTC due to an ACPI setting on your
> platform. Juergen, can you check to see if that was the case for your
> testing platform on dom0 ?
Are you sure it would break? Wouldn't it just fall back to another
clock source, e.g. hpet?
I looked into my test system: seems as if add_rtc_cmos() is returning
before the .legacy.rtc test.
> This highlights a semantic gap issue. From a quick cursory review, I think
> we can address this temporarily by just using a check:
>
> void __init x86_early_init_platform_quirks(void)
> {
> x86_platform.legacy.rtc = 1;
>
> switch (boot_params.hdr.hardware_subarch) {
> case X86_SUBARCH_XEN:
> case X86_SUBARCH_LGUEST:
> case X86_SUBARCH_INTEL_MID:
> - x86_platform.legacy.rtc = 0;
> + if (x86_init.mpparse.get_smp_config != x86_init_uint_noop)
> + x86_platform.legacy.rtc = 0;
No! Why don't you just use the explicit test xen_initial_domain() ?
Juergen
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[PATCH v4 00/14] x86: remove paravirt_enabled "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-07 02:10 +0200
[PATCH v4 06/14] x86/init: use a platform legacy quirk for ebda "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-07 02:10 +0200
Re: [Xen-devel] [PATCH v4 06/14] x86/init: use a platform legacy quirk for ebda David Vrabel <david.vrabel@citrix.com> - 2016-04-07 11:50 +0200
Re: [Xen-devel] [PATCH v4 06/14] x86/init: use a platform legacy quirk for ebda "Luis R. Rodriguez" <mcgrof@suse.com> - 2016-04-07 23:10 +0200
[PATCH v4 10/14] x86/cpu/intel: remove not needed paravirt_enabled() for f00f work around "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-07 02:10 +0200
[PATCH v4 14/14] x86/paravirt: remove paravirt_enabled() "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-07 02:10 +0200
[PATCH v4 13/14] x86/init: rename ebda code file "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-07 02:10 +0200
[PATCH v4 04/14] x86/rtc: replace paravirt rtc check with platform legacy quirk "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-07 02:10 +0200
Re: [Xen-devel] [PATCH v4 04/14] x86/rtc: replace paravirt rtc check with platform legacy quirk David Vrabel <david.vrabel@citrix.com> - 2016-04-07 11:50 +0200
Re: [Xen-devel] [PATCH v4 04/14] x86/rtc: replace paravirt rtc check with platform legacy quirk "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-14 01:10 +0200
Re: [PATCH v4 04/14] x86/rtc: replace paravirt rtc check with platform legacy quirk Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-04-07 15:00 +0200
Re: [PATCH v4 04/14] x86/rtc: replace paravirt rtc check with platform legacy quirk "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-08 02:40 +0200
Re: [PATCH v4 04/14] x86/rtc: replace paravirt rtc check with platform legacy quirk Juergen Gross <jgross@suse.com> - 2016-04-08 07:20 +0200
Re: [PATCH v4 04/14] x86/rtc: replace paravirt rtc check with platform legacy quirk Juergen Gross <jgross@suse.com> - 2016-04-08 08:40 +0200
Re: [PATCH v4 04/14] x86/rtc: replace paravirt rtc check with platform legacy quirk "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-08 09:00 +0200
Re: [PATCH v4 04/14] x86/rtc: replace paravirt rtc check with platform legacy quirk Juergen Gross <jgross@suse.com> - 2016-04-08 09:20 +0200
Re: [PATCH v4 04/14] x86/rtc: replace paravirt rtc check with platform legacy quirk "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-08 09:40 +0200
Re: [PATCH v4 04/14] x86/rtc: replace paravirt rtc check with platform legacy quirk Juergen Gross <jgross@suse.com> - 2016-04-08 10:10 +0200
Re: [PATCH v4 04/14] x86/rtc: replace paravirt rtc check with platform legacy quirk Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-04-08 14:40 +0200
Re: [PATCH v4 04/14] x86/rtc: replace paravirt rtc check with platform legacy quirk "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-08 20:50 +0200
Re: [PATCH v4 04/14] x86/rtc: replace paravirt rtc check with platform legacy quirk "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-08 08:40 +0200
Re: [PATCH v4 04/14] x86/rtc: replace paravirt rtc check with platform legacy quirk Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-04-08 14:30 +0200
[PATCH v4 07/14] tools/lguest: force disable tboot and apm "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-07 02:10 +0200
Re: [PATCH v4 07/14] tools/lguest: force disable tboot and apm Rusty Russell <rusty@rustcorp.com.au> - 2016-04-11 06:00 +0200
[PATCH v4 03/14] tools/lguest: make lguest launcher use X86_SUBARCH_LGUEST explicitly "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-07 02:10 +0200
[PATCH v4 08/14] apm32: remove paravirt_enabled() use "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-07 02:10 +0200
Re: [PATCH v4 08/14] apm32: remove paravirt_enabled() use Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-04-07 15:10 +0200
Re: [PATCH v4 08/14] apm32: remove paravirt_enabled() use "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-08 00:40 +0200
[PATCH v4 12/14] x86, ACPI: parse ACPI_FADT_LEGACY_DEVICES "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-07 02:10 +0200
[PATCH v4 01/14] x86/boot: enumerate documentation for the x86 hardware_subarch "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-07 02:10 +0200
Re: [PATCH v4 01/14] x86/boot: enumerate documentation for the x86 hardware_subarch Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2016-04-07 13:30 +0200
Re: [PATCH v4 01/14] x86/boot: enumerate documentation for the x86 hardware_subarch "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-08 00:40 +0200
[PATCH v4 09/14] x86/tboot: remove paravirt_enabled() "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-07 02:10 +0200
[PATCH v4 02/14] x86/xen: use X86_SUBARCH_XEN for PV guest boots "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-07 02:20 +0200
Re: [Xen-devel] [PATCH v4 02/14] x86/xen: use X86_SUBARCH_XEN for PV guest boots David Vrabel <david.vrabel@citrix.com> - 2016-04-07 11:50 +0200
[PATCH v4 05/14] x86, ACPI: move ACPI_FADT_NO_CMOS_RTC check to ACPI boot code "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-07 02:20 +0200
Re: [Xen-devel] [PATCH v4 00/14] x86: remove paravirt_enabled Juergen Gross <jgross@suse.com> - 2016-04-07 15:30 +0200
[PATCH v4 13/14] x86/init: rename ebda code file "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-07 23:40 +0200
Re: [PATCH v4 00/14] x86: remove paravirt_enabled "Luis R. Rodriguez" <mcgrof@kernel.org> - 2016-04-08 03:20 +0200
Re: [PATCH v4 00/14] x86: remove paravirt_enabled Borislav Petkov <bp@alien8.de> - 2016-04-08 12:30 +0200
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