[+iommu_list]

Application isn't aware of hugepage but a userspace (lower) level stack is
aware of the type of memory being allocated on behalf of application, which
in turn communicates w/ driver via ioctl. I'm trying to make it more
agnostic by using dma_map_sg() when multiple GBs are required by
application. Otherwise, I'm using dmap_map_page(). Admittedly, I'm learning
these concepts/APIs for Linux along the way.

Thanks,
-am


On Sun, Dec 1, 2019 at 7:12 PM Lu Baolu <baolu.lu@linux.intel.com> wrote:

> Hi,
>
> On 12/2/19 11:00 AM, Anand Misra wrote:
> > Thanks, Lu Baolu. This is the dev version we've in our company. I can
> > try on a Ubuntu with a recent kernel version. Although, do you think
> I'm  > going in the right direction? Is it possible to have multiple
> hugepages
> > mapped via iommu to get contiguous mapping for DMA?
> >
>
> You mentioned:
>
> "
> I'm trying to use iommu for multiple hugepages (mmap'ed by process and
> pushed to driver via ioctl). The expectation is to have multiple
> hugepages mapped via iommu with each huge page having an entry in iommu
> (i.e. minimize table walk for DMA). Is this possible?
> "
>
> Currently huge page mapping is hidden in iommu driver according to the
> iommu capability and size of map range. Why do you want to be aware of
> it in driver or even application level?
>
> Best regards,
> baolu
>
> > -am
> >
> >
> > On Sun, Dec 1, 2019 at 6:24 PM Lu Baolu <baolu.lu@linux.intel.com
> > <mailto:baolu.lu@linux.intel.com>> wrote:
> >
> >     Hi,
> >
> >     On 12/2/19 9:46 AM, Anand Misra wrote:
> >      > Hello:
> >      >
> >      > I'm in process of adding iommu support in my driver for a PCIe
> >     device.
> >      > The device doesn't publish ACS/ATS via its config space. I've
> >     following
> >      > config:
> >      >
> >      > Linux cmdline: "intel-iommu=on iommu=pt
> >      > vfio_iommu_type1.allow_unsafe_interrupts=1
> >     pcie_acs_override=downstream"
> >      > Centos kernel: 3.10.0-1062.1.2.el7.x86_64
> >      >
> >
> >     Can you please use the latest kernel for test? 3.10 seems to be
> pretty
> >     old and there are a lot of changes after it.
> >
> >     Best regards,
> >     baolu
> >
>