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From: Thomas Gleixner <tglx@linutronix.de>
To: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: "M. Vefa Bicakci" <m.v.b@runbox.com>,
	"Charles (Chas) Williams" <ciwillia@Brocade.com>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	"x86@kernel.org" <x86@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Borislav Petkov <bp@alien8.de>,
	David Vrabel <david.vrabel@citrix.com>,
	Juergen Gross <jgross@suse.com>,
	xen-devel <xen-devel@lists.xen.org>
Subject: Re: [PATCH] x86/cpuid: Deal with broken firmware once more
Date: Fri, 18 Nov 2016 12:16:55 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.20.1611181214240.3615@nanos> (raw)
In-Reply-To: <96419776-022d-63f9-84c4-7426101f4657@oracle.com>

On Mon, 14 Nov 2016, Boris Ostrovsky wrote:
> On 11/13/2016 06:42 PM, M. Vefa Bicakci wrote:
> 
> > I found out that my domU kernels invoke the 'apic_disable' function
> > because CONFIG_X86_MPPARSE was not enabled in my kernel configuration,
> > which would cause the 'smp_found_config' bit to be unset at boot-up.
> 
> smp_found_config is not the problem, it is usually zero for Xen PV guests.
> 
> What is the problem is that because of your particular config selection
> acpi_mps_check() fails (with the error message that you mention below) and
> that leads to X86_FEATURE_APIC being cleared. And then we indeed switch to
> APIC noop and things go south after that.

Indeed. And what really puzzles me is that Xen manages to bring up a
secondary CPU despite APIC being disabled. 

There are quite some assumptions about no APIC == no SMP in all of x86. Can
we please make Xen behave like anything else?

Thanks,

	tglx

  reply	other threads:[~2016-11-18 11:19 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-02 12:25 [RFC PATCH] perf/x86/intel/rapl: avoid access unallocate memory Sebastian Andrzej Siewior
2016-11-02 22:47 ` Charles (Chas) Williams
2016-11-03 17:47   ` Sebastian Andrzej Siewior
2016-11-04 12:20     ` Charles (Chas) Williams
2016-11-04 18:03       ` Sebastian Andrzej Siewior
2016-11-04 20:42         ` Charles (Chas) Williams
2016-11-04 20:57           ` Sebastian Andrzej Siewior
2016-11-07 16:19   ` Thomas Gleixner
2016-11-07 16:59     ` Charles (Chas) Williams
2016-11-07 20:20       ` Thomas Gleixner
2016-11-08 14:20         ` Charles (Chas) Williams
2016-11-08 14:31           ` Thomas Gleixner
2016-11-08 14:57             ` Charles (Chas) Williams
2016-11-08 16:22               ` Thomas Gleixner
2016-11-09 15:35                 ` [PATCH] x86/cpuid: Deal with broken firmware once more Thomas Gleixner
2016-11-09 15:37                   ` Thomas Gleixner
2016-11-09 16:03                   ` Peter Zijlstra
2016-11-09 16:34                     ` Charles (Chas) Williams
2016-11-09 18:37                       ` Thomas Gleixner
2016-11-09 18:15                   ` Charles (Chas) Williams
2016-11-09 20:27                   ` [tip:x86/urgent] x86/cpu: Deal with broken firmware (VMWare/XEN) tip-bot for Thomas Gleixner
2016-11-11  5:49                     ` Alok Kataria
2016-11-10  3:57                   ` [PATCH] x86/cpuid: Deal with broken firmware once more M. Vefa Bicakci
2016-11-10 10:50                     ` Charles (Chas) Williams
2016-11-10 11:14                       ` Thomas Gleixner
2016-11-12 22:05                       ` M. Vefa Bicakci
2016-11-10 11:13                     ` Thomas Gleixner
2016-11-10 11:39                       ` Peter Zijlstra
2016-11-10 14:02                       ` Boris Ostrovsky
2016-11-10 15:05                         ` Charles (Chas) Williams
2016-11-10 15:31                           ` Boris Ostrovsky
2016-11-10 15:54                             ` Sebastian Andrzej Siewior
2016-11-10 17:15                             ` Thomas Gleixner
2016-11-12 22:05                             ` M. Vefa Bicakci
2016-11-13 18:04                               ` Boris Ostrovsky
2016-11-13 23:42                                 ` M. Vefa Bicakci
2016-11-15  1:21                                   ` Boris Ostrovsky
2016-11-18 11:16                                     ` Thomas Gleixner [this message]
2016-11-18 14:22                                       ` Boris Ostrovsky
2016-11-10 15:12                         ` Thomas Gleixner
2016-11-10 15:38                           ` Boris Ostrovsky
2016-11-10 17:13                             ` Thomas Gleixner
2016-11-10 18:01                               ` Boris Ostrovsky

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