Re: Only one CPU core detected when booting on UEFI

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

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

> 
> 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.

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