linux-kernel - Re: [PATCH] include/linux/vfio.h: Guard powerpc-specific functions with CONFIG_VFIO_SPAPR

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Date:   Thu, 8 Jun 2017 12:32:54 -0300
From:   Murilo Opsfelder Araújo <mopsfelder@...il.com>
To:     Alexey Kardashevskiy <aik@...abs.ru>,
        Michael Ellerman <mpe@...erman.id.au>,
        kbuild test robot <lkp@...el.com>
Cc:     kbuild-all@...org, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org, Alex Williamson <alex.williamson@...hat.com>,
        linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH] include/linux/vfio.h: Guard powerpc-specific functions
 with CONFIG_VFIO_SPAPR_EEH

On 06/08/2017 10:10 AM, Alexey Kardashevskiy wrote:
[...]
> The config you attached in the first mail has CONFIG_VFIO_SPAPR_EEH=m, here
> is my confusion. The config from the link below does not have KVM_BOOK3S_64
> which selects SPAPR_TCE_IOMMU and which in turn selects VFIO_IOMMU_SPAPR_TCE.
> 
> So
> https://github.com/0day-ci/linux/commit/36ed1ddb05e132aa3cfbb610f0f8402a0774da12
> looks correct.

It wasn't me that attached the .config.gz, it was this 0dayci robot.

When CONFIG_VFIO_SPAPR_EEH=m, there is no definition of it in autoconf.h, only
CONFIG_VFIO_SPAPR_EEH_MODULE is defined:

    $ grep 'VFIO_SPAPR_EEH' ./include/generated/autoconf.h
    #define CONFIG_VFIO_SPAPR_EEH_MODULE 1

In this case, `#ifdef CONFIG_VFIO_SPAPR_EEH` will be false. That's why my v1
patch failed with the 0dayci .config and robot reported back.

This was addressed in my v2 patch using the IS_ENABLED() macro, which checks for
both CONFIG_<name> and CONFIG_<name>_MODULE definitions.

-- 
Murilo