From: John Sperbeck <jsperbeck@google.com>
To: tip-bot2@linutronix.de
Cc: linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org,
peterz@infradead.org, rui.zhang@intel.com, tglx@linutronix.de,
x86@kernel.org
Subject: Re: [tip: x86/urgent] x86/acpi: Ignore invalid x2APIC entries
Date: Wed, 22 Nov 2023 22:19:47 +0000 [thread overview]
Message-ID: <20231122221947.781812-1-jsperbeck@google.com> (raw)
In-Reply-To: <169953729188.3135.6804572126118798018.tip-bot2@tip-bot2>
I have a platform with both LOCAL_APIC and LOCAL_X2APIC entries for
each CPU. However, the ids for the LOCAL_APIC entries are all
invalid ids of 255, so they have always been skipped in acpi_parse_lapic()
by this code from f3bf1dbe64b6 ("x86/acpi: Prevent LAPIC id 0xff from being
accounted"):
/* Ignore invalid ID */
if (processor->id == 0xff)
return 0;
With the change in this thread, the return value of 0 means that the
'count' variable in acpi_parse_entries_array() is incremented. The
positive return value means that 'has_lapic_cpus' is set, even though
no entries were actually matched. Then, when the MADT is iterated
with acpi_parse_x2apic(), the x2apic entries with ids less than 255
are skipped and most of my CPUs aren't recognized.
I think the original version of this change was okay for this case in
https://lore.kernel.org/lkml/87pm4bp54z.ffs@tglx/T/
P.S. I could be convinced that the MADT for my platform is somewhat
ill-formed and that I'm relying on pre-existing behavior. I'm not
well-versed enough in the topic to know for sure.
next prev parent reply other threads:[~2023-11-22 22:19 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-02 16:28 [RFC PATCH] x86/acpi: Ignore invalid x2APIC entries Zhang Rui
2023-07-28 12:51 ` Thomas Gleixner
2023-07-28 12:55 ` Thomas Gleixner
2023-07-28 16:47 ` Zhang, Rui
2023-07-29 7:07 ` Thomas Gleixner
2023-07-31 13:04 ` Zhang, Rui
2023-11-09 13:41 ` [tip: x86/urgent] " tip-bot2 for Zhang Rui
2023-11-22 22:17 ` [PATCH] platform/x86: intel_telemetry: Fix kernel doc descriptions John Sperbeck
2023-11-22 22:18 ` [tip: x86/urgent] x86/acpi: Ignore invalid x2APIC entries John Sperbeck
2023-11-22 22:19 ` John Sperbeck [this message]
2023-11-23 12:50 ` Zhang, Rui
2023-12-01 3:25 ` Ashok Raj
2023-12-01 18:08 ` Zhang, Rui
2023-12-01 20:23 ` Ashok Raj
2023-12-02 2:53 ` Zhang, Rui
2023-12-01 8:31 ` Zhang, Rui
2023-12-01 23:32 ` John Sperbeck
2023-12-06 6:58 ` Andres Freund
2023-12-07 2:41 ` Zhang, Rui
2023-12-07 5:10 ` Andres Freund
2023-12-12 17:34 ` Thomas Gleixner
2023-12-13 7:39 ` Zhang, Rui
2023-12-13 14:51 ` Thomas Gleixner
2023-12-14 15:00 ` Zhang, Rui
2023-12-14 21:11 ` Thomas Gleixner
2023-12-15 14:19 ` [PATCH] x86/acpi: Handle bogus MADT APIC tables gracefully Thomas Gleixner
2023-12-15 14:20 ` [tip: x86/urgent] x86/acpi: Ignore invalid x2APIC entries Andres Freund
2023-12-10 11:47 ` Linux regression tracking (Thorsten Leemhuis)
2023-12-18 13:57 ` [tip: x86/urgent] x86/acpi: Handle bogus MADT APIC tables gracefully tip-bot2 for Thomas Gleixner
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