From: Andrew Cooper <andrew.cooper3@citrix.com>
To: xen-devel <xen-devel@lists.xenproject.org>,
Jan Beulich <JBeulich@suse.com>, Wei Liu <wl@xen.org>,
Roger Pau Monne <roger.pau@citrix.com>
Subject: [Xen-devel] HPET interrupt remapping during boot
Date: Tue, 8 Oct 2019 19:30:58 +0100 [thread overview]
Message-ID: <09d5e0bc-074e-90c5-f0a6-60e1be23d92f@citrix.com> (raw)
Hello,
I have no idea if this is a regression or not. I suspect it might not
be, and has always been broken.
Either way, I'm seeing occasional single interrupt remapping errors when
booting a range of Intel systems
(XEN) x2APIC mode is already enabled by BIOS.
(XEN) Using APIC driver x2apic_cluster
...
(XEN) Platform timer is 23.999MHz HPET
(XEN) Detected 2194.922 MHz processor.
...
(XEN) HVM: HAP page sizes: 4kB, 2MB, 1GB
(XEN) alt table ffff82d08047a070 -> ffff82d080486c6c
(XEN) [VT-D]INTR-REMAP: Request device [0000:f0:1f.0] fault index 0,
iommu reg = ffff82c00072d000
(XEN) [VT-D]INTR-REMAP: reason 22 - Present field in the IRTE entry is clear
(XEN) microcode: CPU2 updated from revision 0x5000021 to 0x500002b, date
= 2019-08-12
From other debugging, I know that this happens after CPU 1 (which is a
hyperthread) has passed through start_secondary().
f0:1f.0 is one of the IO-APICs, and if I've cross referenced the DMAR
and APIC tables properly, is the IO-APIC on the PCH, making the
problematic IRQ GSI0.
This suggests that we have an error setting up the timer IRQ (as the
HPET isn't MSI-capable), but we have already allegedly used it
successfully earlier on boot.
I haven't investigated further yet, but it is an intermittent issue
(i.e. doesn't reproduce on each boot). My gut feeling is that we have
something which corrects itself as a side effect of a later action.
~Andrew
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next reply other threads:[~2019-10-08 18:31 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-08 18:30 Andrew Cooper [this message]
2019-10-09 9:31 ` [Xen-devel] HPET interrupt remapping during boot Jan Beulich
2019-10-09 10:11 ` Roger Pau Monné
2019-10-09 10:41 ` Jan Beulich
2019-10-09 11:29 ` Roger Pau Monné
2019-10-09 12:03 ` Jan Beulich
2019-10-09 13:56 ` Roger Pau Monné
2019-10-09 14:59 ` Jan Beulich
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