Re: [dpdk-dev] [PATCH] vfio: retry creating sPAPR DMA window

[Thomas Monjalon <thomas@monjalon.net>]

10/07/2019 12:32, Burakov, Anatoly:
> On 07-Jun-19 3:28 AM, Takeshi Yoshimura wrote:
> > sPAPR allows only page_shift from VFIO_IOMMU_SPAPR_TCE_GET_INFO ioctl.
> > However, Linux 4.17 or before returns incorrect page_shift for Power9.
> > I added the code for retrying creation of sPAPR DMA window.
> > 
> > Signed-off-by: Takeshi Yoshimura <tyos@jp.ibm.com>
> > ---
> >   lib/librte_eal/linux/eal/eal_vfio.c | 26 +++++++++++++++++++++++---
> >   1 file changed, 23 insertions(+), 3 deletions(-)
> > 
> > diff --git a/lib/librte_eal/linux/eal/eal_vfio.c b/lib/librte_eal/linux/eal/eal_vfio.c
> > index 6892a2c14..f16c5c3c0 100644
> > --- a/lib/librte_eal/linux/eal/eal_vfio.c
> > +++ b/lib/librte_eal/linux/eal/eal_vfio.c
> > @@ -1448,9 +1448,29 @@ vfio_spapr_create_new_dma_window(int vfio_container_fd,
> >   	/* create new DMA window */
> >   	ret = ioctl(vfio_container_fd, VFIO_IOMMU_SPAPR_TCE_CREATE, create);
> >   	if (ret) {
> > -		RTE_LOG(ERR, EAL, "  cannot create new DMA window, "
> > -				"error %i (%s)\n", errno, strerror(errno));
> > -		return -1;
> > +		/* try possible page_shift and levels for workaround */
> > +		uint32_t levels;
> > +
> > +		for (levels = 1; levels <= info.ddw.levels; levels++) {
> > +			uint32_t pgsizes = info.ddw.pgsizes;
> 
> +CC POWER maintainer from MAINTAINERS file.
> 
> This is failing compilation on some older distros (Fedora 20, Ubuntu 14.04):
> 
> 
> /root/dpdk/lib/librte_eal/linux/eal/eal_vfio.c: In function 
> ‘vfio_spapr_create_new_dma_window’:
> /root/dpdk/lib/librte_eal/linux/eal/eal_vfio.c:1451:34: error: ‘struct 
> vfio_iommu_spapr_tce_info’ has no member named ‘ddw’
> for (levels = 1; levels <= info.ddw.levels; levels++) {
> ^
> /root/dpdk/lib/librte_eal/linux/eal/eal_vfio.c:1452:27: error: ‘struct 
> vfio_iommu_spapr_tce_info’ has no member named ‘ddw’
> uint32_t pgsizes = info.ddw.pgsizes;
> ^
> /root/dpdk/lib/librte_eal/linux/eal/eal_vfio.c: At top level:
> cc1: error: unrecognized command line option 
> "-Wno-address-of-packed-member" [-Werror]
> cc1: all warnings being treated as errors
> make[7]: *** [eal_vfio.o] Error 1
> make[7]: *** Waiting for unfinished jobs....
> make[6]: *** [eal] Error 2
> make[5]: *** [linux] Error 2
> make[4]: *** [librte_eal] Error 2
> make[3]: *** [lib] Error 2
> make[2]: *** [all] Error 2
> make[1]: *** [pre_install] Error 2
> make: *** [install] Error 2
> 
> 
> Looking at the eal_vfio.h we are handling case of missing sPAPR info/ddw 
> structures, but this isn't simply a case of a missing struct; rather it 
> is an issue of differing definitions between what recent kernels have, 
> and what older kernels had.
> 
> @Thomas Do we still support these older distros?

If the kernel is not maintained, we don't support it.
For most distros, Linux < 3.16 is not maintained.