Re: Re: Xen dom0 linux kernel 3.1 boot failure ptwr_emulate: could not get_page_from_l1e

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

On Tue, Nov 01, 2011 at 01:47:15PM +0100, Tobias Heinlein wrote:
> I'm not sure if it was obvious, but yesterday I noticed that setting the
> "MPS table mode" to 'Disabled' actually made SMP stop working, i.e. the
> kernel only recognized a single CPU. This is of course not an option, so
> I enabled (set to 'Full Table APIC') the setting again and played around
> with my kernel config a bit. The kernel that crashed had
> CONFIG_X86_MPPARSE=y, and if I disable that, it boots fine (with SMP,
> and with the BIOS setting set to 'Full Table APIC').

Hm, that is good to know.
> 
> So, I for one am quite happy now as I finally found a working
> configuration. But I'd still like to know if this is a hardware-specific
> issue, and/or a bug in Xen.

Well,.. I think it just that we hadn't touched any machines that
have MP tables instead of ACPI. Or that have fully populated MP tables.
I presume that there are some ACPI tables, but perhaps not the _PRT ones
(which are the ones we need to parse the IRQ data).

But more importantly - how recent is this machine? 
> 
> Konrad Rzeszutek Wilk wrote, on 10/31/2011 03:08 PM:
> > Oh nice. What does you /proc/interrupts look like compared to
> > baremetal?
> 
> While I was performing all my kernel tests, I saved the outputs of
> `dmesg` and `cat /proc/interrupts`. Sorry for attaching a tarball, but
> I'd like to give you as much information as possible. You'll probably
> only need the latest tests (#5 to #7), but just in case, I also included
> the others.
> 
> Contents of the tarball:
> 
> Baremetal tests:
> xen-hp/1/: MPS mode 'Full Table APIC', CONFIG_X86_MPPARSE=y, SMP working
> xen-hp/2/: MPS mode 'Full Table APIC', CONFIG_X86_MPPARSE=n, SMP working
> xen-hp/3/: MPS mode 'Disabled', CONFIG_X86_MPPARSE=y, SMP not working
> xen-hp/4/: MPS mode 'Disabled', CONFIG_X86_MPPARSE=n, SMP not working
> 
> Xen tests:
> xen-hp/5/: MPS mode 'Disabled', CONFIG_X86_MPPARSE=n, SMP not working
> xen-hp/6/: MPS mode 'Full Table APIC', CONFIG_X86_MPPARSE=n, SMP working
> xen-hp/7/: MPS mode 'Full Table APIC', CONFIG_X86_MPPARSE=y, CRASHES
> 
> (Therefore, #6 is the best working solution; #7 is what originally
> triggered the crash.)
> 
> Thanks.
> 


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