Bug#637308: xen-linux-system-2.6.32-5-xen-amd64: with kernel option 'nosmp', dom0 hangup while init PCI-Express Fusion-MPT SAS
On Wed, Sep 07, 2011 at 01:01:06PM -0400, Konrad Rzeszutek Wilk wrote:
> > Looking at this again: this problem only really applies to dom0, and the
> > new code won't even build in a domU-only kernel config with
> > CONFIG_X86_IO_APIC unset. I think we actually need something like:
>
> Ok, that is Ok I think? We don't care about domU for this?
>
> Or is it that it will cause bootup issues _with_ domU's that are built
> as UP? That is not the case - as the smp.c won't be even built
>
> I am not sure what the concern here is...
As I understand it, the kernel won't work in dom0 if the (PV) IOAPIC is
disabled. CONFIG_XEN_DOM0 depends on CONFIG_X86_IO_APIC and we're now
trying to catch the case where IOAPIC support is disabled at boot.
However, in domU, IOAPIC support is not required (right?). CONFIG_XEN
does not depend on CONFIG_X86_IO_APIC, so the following configuration
is possible:
CONFIG_SMP=y
CONFIG_XEN=y
# CONFIG_XEN_DOM0 is not set
# CONFIG_X86_IO_APIC is not set
And with this configuration the test for disabled IOAPIC support would
fail to compile.
Ben.
--
Ben Hutchings
We get into the habit of living before acquiring the habit of thinking.
- Albert Camus
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