[vbox-dev] New kernel error message when running 4.13 as guest

[Frank Mehnert]

Hi Hans,

see function apic_check_deadline_errata() in arch/x86/kernel/apic/apic.c: This
message is printed if Linux is running on certain Intel CPU families if the
determined microcode version is less than a certain value. As the determined
microcode version is always 0 on VirtualBox, Linux will always complain when
running on one of the listed Intel CPU families.

Kind regards,

Frank

On Mittwoch, 26. Juli 2017 22:17:22 CEST Hans de Goede wrote:
> Hi Michal,
> 
> On 26-07-17 17:18, Michal Necasek wrote:
> > 
> >     Hi Hans,
> > 
> >   The message is harmless. It's triggered because VirtualBox currently does not expose the host CPU microcode revision to guest operating systems. I don't think we want to do that without fully understanding what sorts of assumptions operating systems might make when they see the actual revision.
> > 
> >   At any rate, VirtualBox currently doesn't support TSC deadline timers so the message is simply noise.
> 
> Thank you for your reaction. I understand that the message is just noise, but it would
> still be nice to do something about it, Linux distributions have gone through great
> efforts to offer a smooth boot experience without scary text-messages and an error
> like this breaks that part of the user-experience.
> 
> I wonder why the kernel prints the message at all if vbox does not support
> TSC deadline timers, could it be that somehow the capability bit for that
> gets leaked from the host to the guest even though it is not supported ?
> 
> Regards,
> 
> Hans
> 
> > ----- Original Message -----
> > From: hdegoede at redhat.com
> > To: vbox-dev at virtualbox.org
> > Sent: Monday, July 24, 2017 9:49:56 AM GMT +01:00 Amsterdam / Berlin / Bern / Rome / Stockholm / Vienna
> > Subject: [vbox-dev] New kernel error message when running 4.13 as guest
> > 
> > Hi all,
> > 
> > I just upgraded a vbox guest to 4.13, the good news is
> > everything works fine, but one thing which I noticed, which
> > would be nice to fix is this new error message:
> > 
> > [    0.000000] [Firmware Bug]: TSC_DEADLINE disabled due to Errata; please update microcode to version: 0xb2 (or later)
> > 
> > This is on a Skylake host with no special settings done
> > to the guest (I selected the Fedora 64 bit template
> > when installing).
> > 
> > Regards,
> > 
> > Hans
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-- 
Dr.-Ing. Frank Mehnert | Software Development Director, VirtualBox
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