Re: Only one CPU core detected when booting on UEFI

[Xiao-Long Chen <chenxiaolong@cxl.epac.to>]

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Thanks for the reply! I'll respond inline.

On Fri, Dec 21, 2012 at 2:59 PM, Konrad Rzeszutek Wilk <
konrad.wilk@oracle.com> wrote:

> On Sun, Dec 16, 2012 at 02:37:59AM -0500, Xiao-Long Chen wrote:
> > Hi Xen developers,
> >
> > I have been having a problem where only one CPU core is being detected.
> > I'm using a Lenovo W520 with a UEFI firmware and an Intel Core i7
> > 2720qm (4 real cores, 4 virtual cores). When I boot, I see
> > "Dom0 has maximum 1 VCPUs", or something similar, scroll by.
>
> Ooh.

>
> > In addition, only 10 GB out of my 12 GB of memory is recognized and
> > ACPI is not working properly (CPU frequency scaling and battery info
> > are not reported).
> >
> > This problem has been reported before (for the same laptop too) here:
> > http://lists.xen.org/archives/html/xen-devel/2012-06/msg00087.html but
> > unfortunately, the person who sent the message didn't reply with more
> > information.
> >
> > Here are the outputs of dmesg with and without Xen:
> >
> > Without Xen: http://paste.kde.org/626222/raw/
> > With Xen: http://paste.kde.org/626228/raw/
>
> Hm, this:
> [    0.000000] ACPI BIOS Bug: Error: A valid RSDP was not found
> (20120913/tbxfroot-219)
>
> is a problem. The workaround was mentioned on the mailing list to use
> the acpi_rsdp=0xbabfe000
>

I tried booting with this, but the kernel immediately crashed
(I think). I booted with 'acpi_rsdp=0xbabfe000' and without 'quiet' and
the system hangs while loading the initramfs. I could not see any sort
of response on the system and could not ssh in.


>
> >
> > and some information from xl:
> >
> > xl vcpu-list: http://paste.kde.org/626234/raw/
> > xl info: http://paste.kde.org/626240/raw/
> > xl dmesg: http://paste.kde.org/626246/raw/
>
> And Xen has the same issue:
>
> (XEN) ACPI Error (tbxfroot-0218): A valid RSDP was not found [20070126]
>
> And it looks to be running in a legacy state - with no calls to EFI.
> >
> > This is my first time venturing into Xen territory, so please let me
> > know if there's any other information needed.
>
> Did you try to boot xen.efi by itself - without using the GRUB loader?
> There is a nice writeup of how to do this in docs/misc/efi.markdown.
>

Booting from xen.efi, I see "Dom0 has maximum 8 VCPUs" as expected, but
Linux is still seeing only one core. In addition, my keyboard and mouse
do not work (internal laptop PS/2). I was able to get the dmesg and
'xl dmesg' outputs from ssh though:

dmesg (no xen): http://paste.kde.org/629684/raw/
dmesg (xen.efi): http://paste.kde.org/629690/raw/
xl dmesg: http://paste.kde.org/629696/raw/

The system is incredibly sluggish as when booted with GRUB, but that
may just be due to one core being available.


>
> Also CC-ing Daniel if he has some ideas.
>

Thanks a lot!

Xiao-Long Chen


> >
> > I'm not sure if it helps, but I'd also like to point out that I had a
> > similar problem with Linux back around July 20, 2011, when I got my
> > computer. I could work around the issue by booting with "noapic". I'm
> > not sure which kernel version fixed the issue as I booted with that
> > option for quite a while. The kernel version, at the time, was 3.0.
> >
> > I am glad to help in any way I can. I'm excited to get Xen working!
> > I'm confortable with compiling the kernel or xen if necessary.
> >
> > Thanks in advance!
> >
> > Xiao-Long Chen
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@lists.xen.org
> > http://lists.xen.org/xen-devel
> >
>

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