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From: "Burakov, Anatoly" <anatoly.burakov@intel.com>
To: Stephen Hemminger <stephen@networkplumber.org>, "dev@dpdk.org"
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Thread-Topic: [dpdk-dev] [PATCH] vfio: don't silently drop VFIO support
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Date: Tue, 21 Apr 2015 09:34:27 +0000
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Subject: Re: [dpdk-dev] [PATCH] vfio: don't silently drop VFIO support
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Hi Stephen,

> The VFIO_PRESENT #define was a landmine and we hit it.
> The DPDK has a config system and it should be used rather than silently
> dropping a feature during build only to have it fail at run time.
>=20
> If VFIO is configured, and the kernel headers are not present the build
> should fail. Rather than leaving developers puzzling why the build system
> (with old kernel headers) produced non functioning DPDK and their system
> (with new kernel headers) produced correctly working DPDK.
>=20
> As a matter of policy, really no code should be looking at <linux/version=
.h>
> except for kernel drivers with compat files.

In theory, I agree with you. In practice however, this change will uncondit=
ionally break builds on pre-VFIO kernels (<3.6). This may be OK now, but wa=
sn't OK at the time it was developed because pre-VFIO kernels were still ve=
ry much prevalent. AFAIK, VFIO is enabled by default, so maybe we should di=
sable it in the default configs?

Thanks,
Anatoly