Re: [tip:x86/urgent] x86/kconfig: Add a Kconfig shortcut for building working KVM guest kernels

David Rientjes
2013-05-01T23:16:45Z

On Thu, 2 May 2013, Borislav Petkov wrote:

> > It means your patch is incomplete.
>
> I'll gladly test and ack a patch which makes it complete.
>
> Simple exercises in rhetoric about what does and what doesn't make sense
> means a rat's ass to me. You need to show me a *real* use case which you
> *actually* hit and this patch breaks it.
>

What makes sense = a build that works.

You reported the breakage yourself:

arch/x86/built-in.o:(.data+0x2a0): undefined reference to `native_setup_msi_irqs'
arch/x86/built-in.o:(.data+0x2a8): undefined reference to `native_teardown_msi_irq'

That's because of this:

warning: (KVM_GUEST_COMMON_OPTIONS && AMD_IOMMU) selects PCI_MSI which has unmet direct dependencies (PCI && ARCH_SUPPORTS_MSI)

So you're missing CONFIG_X86_LOCAL_APIC and/or CONFIG_X86_IO_APIC, as
already stated. Those are strict requirements for your
CONFIG_KVM_GUEST_COMMON_OPTIONS to build. I suggest depending on them,
most configs already have them.

You'll probably also want to depend on NET_CORE since it requires that as
well.

That would probably make your patch complete. Ingo does a lot of
randconfig testing himself, so he'll probably run into these same issues,
I don't think the "aww, shucks, that config doesn't make sense, we can
allow the build to break" excuse will work too well.