RE: [PATCH 2/4] vfio: add VFIO IOMMUFD support

["Xing, Beilei" <beilei.xing@intel.com>]

> -----Original Message-----
> From: Stephen Hemminger <stephen@networkplumber.org>
> Sent: Saturday, December 23, 2023 1:17 AM
> To: Xing, Beilei <beilei.xing@intel.com>
> Cc: Burakov, Anatoly <anatoly.burakov@intel.com>; dev@dpdk.org;
> thomas@monjalon.net; ferruh.yigit@amd.com; Richardson, Bruce
> <bruce.richardson@intel.com>; chenbox@nvidia.com; Cao, Yahui
> <yahui.cao@intel.com>
> Subject: Re: [PATCH 2/4] vfio: add VFIO IOMMUFD support
> 
> On Fri, 22 Dec 2023 19:44:51 +0000
> beilei.xing@intel.com wrote:
> 
> > diff --git a/lib/eal/include/rte_vfio.h b/lib/eal/include/rte_vfio.h
> > index 22832afd0f..7a9b26b0f7 100644
> > --- a/lib/eal/include/rte_vfio.h
> > +++ b/lib/eal/include/rte_vfio.h
> > @@ -17,6 +17,8 @@ extern "C" {
> >  #include <stdbool.h>
> >  #include <stdint.h>
> >
> > +#include <rte_compat.h>
> > +
> >  /*
> >   * determine if VFIO is present on the system
> >   */
> > @@ -28,6 +30,9 @@ extern "C" {
> >  #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 0, 0)  #define
> > HAVE_VFIO_DEV_REQ_INTERFACE  #endif /* kernel version >= 4.0.0 */
> > +#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 6, 0) #define
> > +VFIO_IOMMUFD_PRESENT #endif /* kernel version >= 6.6.0 */
> >  #endif /* RTE_EAL_VFIO */
> 
> Depending on kernel version macro is a mistake because many enterprise
> distro's backport features and do not change kernel version.

Make sense. We defined VFIO_IOMMUFD_PRESENT with reference to
VFIO_PRESENT. Do you have suggestion for this point? Thanks a lot.

> Also, it means the build and target machine have to be same kernel version.