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From: Jan Kiszka <jan.kiszka@siemens.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	x86@kernel.org
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: x86: Spurious vectors not handled robustly
Date: Mon, 24 Jun 2019 12:00:00 +0200	[thread overview]
Message-ID: <e525108f-3749-4e1d-1ac2-0d0a2655f15f@siemens.com> (raw)

Hi all,

probably since "x86: Avoid building unused IRQ entry stubs" (2414e021ac8d), the 
kernel can no longer tell spurious IRQs by the APIC apart from spuriously 
triggered unused vectors. We've managed to trigger such a cause with the 
Jailhouse hypervisor (incorrectly injected MANAGED_IRQ_SHUTDOWN_VECTOR), and the 
result was not only a misreport of the vector number (0xff instead of 0xef - 
took me a while...), but also stalled interrupts of equal and lower priority 
because a spurious interrupt is not (and must not be) acknowledged.

How to address that best? I would say we should at least have separate entry 
paths for APIC interrupt vs. vectors, to improve robustness in the faulty case.

Jan

-- 
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux

             reply	other threads:[~2019-06-24 10:00 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-24 10:00 Jan Kiszka [this message]
2019-06-24 10:09 ` x86: Spurious vectors not handled robustly Thomas Gleixner
2019-06-24 10:21   ` Jan Kiszka
2019-06-24 10:37     ` Thomas Gleixner
2019-06-24 13:46       ` Thomas Gleixner
2019-06-24 15:26         ` Thomas Gleixner

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