Re: [Xen-devel] [Xen-users] Only one CPU available to Xen? (nr_cpus : 1)

[George Dunlap <dunlapg@xxxxxxxxx>]

On Tue, Mar 6, 2018 at 10:15 AM, Andrew Cooper
<andrew.cooper3@xxxxxxxxxx> wrote:
> On 06/03/18 10:04, George Dunlap wrote:
>> [Moving over to xen-devel, cc'ing a few people]
>>
>> On Tue, Mar 6, 2018 at 8:16 AM, John Naggets <hostingnuggets@xxxxxxxxx> 
>> wrote:
>>> Hi George,
>>>
>>> You will find the output of "xl dmesg" below. I also managed to
>>> reproduce this problem on another test server. That test server is an
>>> IBM System x3250 M5 server which uses UEFI. So the hardware is not at
>>> fault.
>>>
>>> Regards,
>>> John
>>>
>>> (XEN) Xen version 4.9.0 (Ubuntu 4.9.0-0ubuntu3)
>>> (stefan.bader@xxxxxxxxxxxxx) (gcc (Ubuntu 7.2.0-8ubuntu2) 7.2.0)
>>> debug=n  Fri Oct 13 15:58:41 UTC 2017
>>> (XEN) Bootloader: GRUB 2.02~beta3-4ubuntu7
>>> (XEN) Command line: placeholder dom0_mem=4G,max:4G dom0_max_vcpus=2
>>> dom0_vcpus_pin no-real-mode edd=off
>>> (XEN) Xen image load base address: 0
>>> (XEN) Video information:
>>> (XEN)  VGA is text mode 80x25, font 8x16
>>> (XEN) Disc information:
>>> (XEN)  Found 0 MBR signatures
>>> (XEN)  Found 0 EDD information structures
>>> (XEN) Multiboot-e820 RAM map:
>>> (XEN)  0000000000000000 - 00000000000a0000 (usable)
>>> (XEN)  00000000000a0000 - 0000000000100000 (reserved)
>>> (XEN)  0000000000100000 - 000000009e3f8000 (usable)
>>> (XEN)  000000009e3f8000 - 000000009e568000 (ACPI data)
>>> (XEN)  000000009e568000 - 000000009efe1000 (ACPI NVS)
>>> (XEN)  000000009efe1000 - 00000000a0117000 (usable)
>>> (XEN)  00000000a0117000 - 00000000ab6b9000 (reserved)
>>> (XEN)  00000000ab6b9000 - 00000000ab865000 type 20
>>> (XEN)  00000000ab865000 - 00000000af3fc000 (usable)
>>> (XEN)  00000000af3fc000 - 00000000af42e000 (reserved)
>>> (XEN)  00000000af42e000 - 00000000af800000 (usable)
>>> (XEN)  00000000af800000 - 00000000d0000000 (reserved)
>>> (XEN)  00000000fd000000 - 00000000fe800000 (reserved)
>>> (XEN)  00000000fed20000 - 00000000fed45000 (reserved)
>>> (XEN)  00000000ff000000 - 0000000100000000 (reserved)
>>> (XEN)  0000000100000000 - 0000000840000000 (usable)
>>> (XEN) New Xen image base address: 0xaec00000
>>> (XEN) ACPI Error (tbxfroot-0217): A valid RSDP was not found [20070126]
>> Here's the reason Xen only sees one pcpu: It can't find the ACPI table
>> which tells it everything else about the system.
>>
>> Jan / Boris, any ideas here?
>
> Upgrade Grub to 2.02.
>
> The problem here is that Grub is starting EFI, but doesn't pass the EFI
> details to Xen, and Xen therefore cannot locate the RSDP.
>
> Alternatively, switch back to legacy boot, at which point it will all
> start working again.

Would it make sense to add a hint here to the error message?  Something like:

"WARNING: Xen couldn't find an RSDP table.  If you're booting an EFI
system under grub, make sure your grub is up-to-date, try
direct-booting xen.efi, or downgrading to legacy boot."

 -George

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel