[+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 <[email protected]> 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 <[email protected] > > <mailto:[email protected]>> 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 > > >
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