[dpdk-dev] [PATCH v2] vfio: noiommu check error handling

[Jonas Pfefferle1]

Thomas Monjalon <thomas at monjalon.net> wrote on 11/07/2017 10:40:15 AM:

> From: Thomas Monjalon <thomas at monjalon.net>
> To: Jonas Pfefferle1 <JPF at zurich.ibm.com>, anatoly.burakov at intel.com
> Cc: dev at dpdk.org
> Date: 11/07/2017 10:40 AM
> Subject: Re: [dpdk-dev] [PATCH v2] vfio: noiommu check error handling
>
> 07/11/2017 10:05, Jonas Pfefferle1:
> > Thomas Monjalon <thomas at monjalon.net> wrote on 11/06/2017 09:25:15 PM:
> >
> > > From: Thomas Monjalon <thomas at monjalon.net>
> > > To: Jonas Pfefferle <jpf at zurich.ibm.com>, anatoly.burakov at intel.com
> > > Cc: dev at dpdk.org
> > > Date: 11/06/2017 09:55 PM
> > > Subject: Re: [dpdk-dev] [PATCH v2] vfio: noiommu check error handling
> > >
> > > 31/10/2017 16:59, Jonas Pfefferle:
> > > > Check and report errors on open/read in noiommu check.
> > > >
> > > > Signed-off-by: Jonas Pfefferle <jpf at zurich.ibm.com>
> > >
> > > I cannot decide to apply this patch as it does not explain what
> > > it is fixing, and as it is not reviewed.
> > >
> >
> > This patch adds error handling and logging to the noiommu check.
> > Also, on older kernels when the noiommu_enable file does not exist it
> > assumes noiommu is not enabled instead of returning -1.
> > Note that in rte_pci_get_iommu_class (drivers/bus/pci/linux/pci.c)
> > is the only usage of the function and it assumes return == 1:
> > noiommu is enabled any other return value noiommu disabled, i.e.
> > my code change does not change the behavior of this function.
> > We might want to check for errors in rte_pci_get_iommu_class
> > as well since assuming it is not enabled when we cannot open
> > and read it might lead to iova == VA being used even if noiommu is
> > enabled.
> >
> > All this comes back to what I proposed before: instead of
> > the noiommu and PPC64 check we should decide which iova mode
> > to use depending on the iommu types available.
> > The type should be already available at the point where we
> > decide on the iova type.
> > (iommu types supported is checked by vfio_get_container_fd)
>
> Is there something urgent for 17.11?
> Or can it be refined in 18.02?

Nothing urgent. We can refine this for 18.02.


>
> Anatoly, any thought?
>